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Uhlířová H, Stibůrek M, Pikálek T, Gomes A, Turtaev S, Kolbábková P, Čižmár T. "There's plenty of room at the bottom": deep brain imaging with holographic endo-microscopy. Neurophotonics 2024; 11:S11504. [PMID: 38250297 PMCID: PMC10798506 DOI: 10.1117/1.nph.11.s1.s11504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/09/2023] [Accepted: 12/14/2023] [Indexed: 01/23/2024]
Abstract
Significance Over more than 300 years, microscopic imaging keeps providing fundamental insights into the mechanisms of living organisms. Seeing microscopic structures beyond the reach of free-space light-based microscopy, however, requires dissection of the tissue-an intervention seriously disturbing its physiological functions. The hunt for low-invasiveness tools has led a growing community of physicists and engineers into the realm of complex media photonics. One of its activities represents exploiting multimode optical fibers (MMFs) as ultra-thin endoscopic probes. Employing wavefront shaping, these tools only recently facilitated the first peeks at cells and their sub-cellular compartments at the bottom of the mouse brain with the impact of micro-scale tissue damage. Aim Here, we aim to highlight advances in MMF-based holographic endo-microscopy facilitating microscopic imaging throughout the whole depth of the mouse brain. Approach We summarize the important technical and methodological prerequisites for stabile high-resolution imaging in vivo. Results We showcase images of the microscopic building blocks of brain tissue, including neurons, neuronal processes, vessels, intracellular calcium signaling, and red blood cell velocity in individual vessels. Conclusions This perspective article helps to understand the complexity behind the technology of holographic endo-microscopy, summarizes its recent advances and challenges, and stimulates the mind of the reader for further exploitation of this tool in the neuroscience research.
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Affiliation(s)
- Hana Uhlířová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Miroslav Stibůrek
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Tomáš Pikálek
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - André Gomes
- Leibniz Institute of Photonic Technology, Jena, Germany
| | | | - Petra Kolbábková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Tomáš Čižmár
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
- Leibniz Institute of Photonic Technology, Jena, Germany
- Friedrich Schiller University Jena, Institute of Applied Optics, Jena, Germany
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2
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Xia F, Rimoli CV, Akemann W, Ventalon C, Bourdieu L, Gigan S, de Aguiar HB. Neurophotonics beyond the surface: unmasking the brain's complexity exploiting optical scattering. Neurophotonics 2024; 11:S11510. [PMID: 38617592 PMCID: PMC11014413 DOI: 10.1117/1.nph.11.s1.s11510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/07/2024] [Accepted: 03/14/2024] [Indexed: 04/16/2024]
Abstract
The intricate nature of the brain necessitates the application of advanced probing techniques to comprehensively study and understand its working mechanisms. Neurophotonics offers minimally invasive methods to probe the brain using optics at cellular and even molecular levels. However, multiple challenges persist, especially concerning imaging depth, field of view, speed, and biocompatibility. A major hindrance to solving these challenges in optics is the scattering nature of the brain. This perspective highlights the potential of complex media optics, a specialized area of study focused on light propagation in materials with intricate heterogeneous optical properties, in advancing and improving neuronal readouts for structural imaging and optical recordings of neuronal activity. Key strategies include wavefront shaping techniques and computational imaging and sensing techniques that exploit scattering properties for enhanced performance. We discuss the potential merger of the two fields as well as potential challenges and perspectives toward longer term in vivo applications.
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Affiliation(s)
- Fei Xia
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
| | - Caio Vaz Rimoli
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Walther Akemann
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Cathie Ventalon
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Laurent Bourdieu
- Université PSL, Institut de Biologie de l’ENS, École Normale Supérieure, CNRS, INSERM, Paris, France
| | - Sylvain Gigan
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
| | - Hilton B. de Aguiar
- Sorbonne Université, Collège de France, Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Paris, France
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3
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Wu XY, Feng HY, Wan F, Wei M, Guo C, Cai L, Wu F, Jiang ZH, Kang L, Hong W, Werner DH. An Ultrathin, Fast-Response, Large-Scale Liquid-Crystal-Facilitated Multi-Functional Reconfigurable Metasurface for Comprehensive Wavefront Modulation. Adv Mater 2024:e2402170. [PMID: 38587064 DOI: 10.1002/adma.202402170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/01/2024] [Indexed: 04/09/2024]
Abstract
The rapid advancement of prevailing communication/sensing technologies necessitates cost-effective millimeter-wave arrays equipped with a massive number of phase-shifting cells to perform complicated beamforming tasks. Conventional approaches employing semiconductor switch/varactor components or tunable materials encounter obstacles such as quantization loss, high cost, high complexity, and limited adaptability for realizing large-scale arrays. Here, a low-cost, ultrathin, fast-response, and large-scale solution relying on metasurface concepts combined together with liquid crystal (LC) materials requiring a layer thickness of only 5 µm is reported. Rather than immersing resonant structures in LCs, a joint material-circuit-based strategy is devised, via integrating deep-subwavelength-thick LCs into slow-wave structures, to achieve constitutive metacells with continuous phase shifting and stable reflectivity. An LC-facilitated reconfigurable metasurface sub-system containing more than 2300 metacells is realized with its unprecedented comprehensive wavefront manipulation capacity validated through various beamforming functions, including beam focusing/steering, reconfigurable vortex beams, and tunable holograms, demonstrating a milli-second-level function-switching speed. The proposed methodology offers a paradigm shift for modulating electromagnetic waves in a non-resonating broadband fashion with fast-response and low-cost properties by exploiting functionalized LC-enabled metasurfaces. Moreover, this extremely agile metasurface-enabled antenna technology will facilitate a transformative impact on communication/sensing systems and empower new possibilities for wavefront engineering and diffractive wave calculation/inference.
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Affiliation(s)
- Xin Yu Wu
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Hong Yuan Feng
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Fengshuo Wan
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Meng Wei
- Central Research Institute, BOE Technology Group Company Ltd., Beijing, 100176, China
| | - Chong Guo
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Longzhu Cai
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Fan Wu
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Zhi Hao Jiang
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Lei Kang
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Wei Hong
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Douglas H Werner
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
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4
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Xia F, Rimoli CV, Akemann W, Ventalon C, Bourdieu L, Gigan S, de Aguiar HB. Neurophotonics beyond the Surface: Unmasking the Brain's Complexity Exploiting Optical Scattering. ArXiv 2024:arXiv:2403.14809v1. [PMID: 38562443 PMCID: PMC10984001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The intricate nature of the brain necessitates the application of advanced probing techniques to comprehensively study and understand its working mechanisms. Neurophotonics offers minimally invasive methods to probe the brain using optics at cellular and even molecular levels. However, multiple challenges persist, especially concerning imaging depth, field of view, speed, and biocompatibility. A major hindrance to solving these challenges in optics is the scattering nature of the brain. This perspective highlights the potential of complex media optics, a specialized area of study focused on light propagation in materials with intricate heterogeneous optical properties, in advancing and improving neuronal readouts for structural imaging and optical recordings of neuronal activity. Key strategies include wavefront shaping techniques and computational imaging and sensing techniques that exploit scattering properties for enhanced performance. We discuss the potential merger of the two fields as well as potential challenges and perspectives toward longer term in vivo applications.
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Affiliation(s)
- Fei Xia
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Caio Vaz Rimoli
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Walther Akemann
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Cathie Ventalon
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Laurent Bourdieu
- Institut de Biologie de l'ENS (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, France
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
| | - Hilton B de Aguiar
- Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, 24 rue Lhomond, 75005 Paris, France
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5
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Cecconi V, Kumar V, Bertolotti J, Peters L, Cutrona A, Olivieri L, Pasquazi A, Totero Gongora JS, Peccianti M. Terahertz Spatiotemporal Wave Synthesis in Random Systems. ACS Photonics 2024; 11:362-368. [PMID: 38405391 PMCID: PMC10885209 DOI: 10.1021/acsphotonics.3c01671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 02/27/2024]
Abstract
Complex media have emerged as a powerful and robust framework to control light-matter interactions designed for task-specific optical functionalities. Studies on wavefront shaping through disordered systems have demonstrated optical wave manipulation capabilities beyond conventional optics, including aberration-free and subwavelength focusing. However, achieving arbitrary and simultaneous control over the spatial and temporal features of light remains challenging. In particular, no practical solution exists for field-level arbitrary spatiotemporal control of wave packets. A new paradigm shift has emerged in the terahertz frequency domain, offering methods for absolute time-domain measurements of the scattered electric field, enabling direct field-based wave synthesis. In this work, we report the experimental demonstration of field-level control of single-cycle terahertz pulses on arbitrary spatial points through complex disordered media.
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Affiliation(s)
- Vittorio Cecconi
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Vivek Kumar
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Jacopo Bertolotti
- Department
of Physics and Astronomy, University of
Exeter, Exeter, Devon EX4 4QL, U.K.
| | - Luke Peters
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Antonio Cutrona
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Luana Olivieri
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Alessia Pasquazi
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Juan Sebastian Totero Gongora
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
| | - Marco Peccianti
- Emergent
Photonics Research Centre, Department of Physics, School of Science, Loughborough University, Loughborough LE11 3TU, U.K.
- Emergent
Photonics Lab (EPic), Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH, U.K.
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6
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Cui Z, Xia S, Shen L, Zheng B, Chen H, Wu Y. Polariton Microfluidics for Nonreciprocal Dragging and Reconfigurable Shaping of Polaritons. Nano Lett 2024; 24:1360-1366. [PMID: 38252685 DOI: 10.1021/acs.nanolett.3c04362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Dielectric environment engineering is an efficient and general approach to manipulating polaritons. Liquids serving as the surrounding media of polaritons have been used to shift polariton dispersions and tailor polariton wavefronts. However, those liquid-based methods have so far been limited to their static states, not fully unleashing the promise offered by the mobility of liquids. Here, we propose a microfluidic strategy for polariton manipulation by merging polaritonics with microfluidics. The diffusion of fluids causes gradient refractive indices over microchannels, which breaks the symmetry of polariton dispersions and realizes the microfluidic analogue to nonreciprocal polariton dragging. Based on polariton microfluidics, we also designed a set of on-chip polaritonic elements to actively shape polaritons, including planar lenses, off-axis lenses, Janus lenses, bends, and splitters. Our strategy expands the toolkit for the manipulation of polaritons at the subwavelength scale and possesses potential in the fields of polariton biochemistry and molecular sensing.
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Affiliation(s)
- Zhenyang Cui
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
| | - Sihao Xia
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
| | - Lian Shen
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
| | - Bin Zheng
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
| | - Hongsheng Chen
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
| | - Yingjie Wu
- State Key Laboratory of Extreme Photonics and Instrumentation, ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 310027, China
- International Joint Innovation Center, The Electromagnetics Academy at Zhejiang University, Zhejiang University, Haining 314400, China
- Key Laboratory of Advanced Micro/Nano Electronic Devices & Smart Systems of Zhejiang, Jinhua Institute of Zhejiang University, Zhejiang University, Jinhua 321099, China
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Li H, Yu Z, Zhong T, Lai P. Performance enhancement in wavefront shaping of multiply scattered light: a review. J Biomed Opt 2024; 29:S11512. [PMID: 38125718 PMCID: PMC10732255 DOI: 10.1117/1.jbo.29.s1.s11512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
Significance In nonballistic regime, optical scattering impedes high-resolution imaging through/inside complex media, such as milky liquid, fog, multimode fiber, and biological tissues, where confocal and multiphoton modalities fail. The significant tissue inhomogeneity-induced distortions need to be overcome and a technique referred as optical wavefront shaping (WFS), first proposed in 2007, has been becoming a promising solution, allowing for flexible and powerful light control. Understanding the principle and development of WFS may inspire exciting innovations for effective optical manipulation, imaging, stimulation, and therapy at depths in tissue or tissue-like complex media. Aim We aim to provide insights about what limits the WFS towards biomedical applications, and how recent efforts advance the performance of WFS among different trade-offs. Approach By differentiating the two implementation directions in the field, i.e., precompensation WFS and optical phase conjugation (OPC), improvement strategies are summarized and discussed. Results For biomedical applications, improving the speed of WFS is most essential in both directions, and a system-compatible wavefront modulator driven by fast apparatus is desired. In addition to that, algorithm efficiency and adaptability to perturbations/noise is of concern in precompensation WFS, while for OPC significant improvements rely heavily on integrating physical mechanisms and delicate system design for faster response and higher energy gain. Conclusions Substantial improvements in WFS implementations, from the aspects of physics, engineering, and computing, have inspired many novel and exciting optical applications that used to be optically inaccessible. It is envisioned that continuous efforts in the field can further advance WFS towards biomedical applications and guide our vision into deep biological tissues.
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Affiliation(s)
- Huanhao Li
- Hong Kong Polytechnic University, Department of Biomedical Engineering, Hong Kong, China
- Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen, China
| | - Zhipeng Yu
- Hong Kong Polytechnic University, Department of Biomedical Engineering, Hong Kong, China
- Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen, China
| | - Tianting Zhong
- Hong Kong Polytechnic University, Department of Biomedical Engineering, Hong Kong, China
- Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen, China
| | - Puxiang Lai
- Hong Kong Polytechnic University, Department of Biomedical Engineering, Hong Kong, China
- Hong Kong Polytechnic University, Shenzhen Research Institute, Shenzhen, China
- Hong Kong Polytechnic University, Photonics Research Institute, Hong Kong, China
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8
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Ding C, Shao R, He Q, Li LS, Yang J. Wavefront shaping improves the transparency of the scattering media: a review. J Biomed Opt 2024; 29:S11507. [PMID: 38089445 PMCID: PMC10711682 DOI: 10.1117/1.jbo.29.s1.s11507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 11/21/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023]
Abstract
Significance Wavefront shaping (WFS) can compensate for distortions by optimizing the wavefront of the input light or reversing the transmission matrix of the media. It is a promising field of research. A thorough understanding of principles and developments of WFS is important for optical research. Aim To provide insight into WFS for researchers who deal with scattering in biomedicine, imaging, and optical communication, our study summarizes the basic principles and methods of WFS and reviews recent progress. Approach The basic principles, methods of WFS, and the latest applications of WFS in focusing, imaging, and multimode fiber (MMF) endoscopy are described. The practical challenges and prospects of future development are also discussed. Results Data-driven learning-based methods are opening up new possibilities for WFS. High-resolution imaging through MMFs can support small-diameter endoscopy in the future. Conclusion The rapid development of WFS over the past decade has shown that the best solution is not to avoid scattering but to find ways to correct it or even use it. WFS with faster speed, more optical modes, and more modulation degrees of freedom will continue to drive exciting developments in various fields.
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Affiliation(s)
- Chunxu Ding
- Shanghai Jiao Tong University, School of Electronic Information and Electrical Engineering, Shanghai, China
| | - Rongjun Shao
- Shanghai Jiao Tong University, School of Electronic Information and Electrical Engineering, Shanghai, China
| | - Qiaozhi He
- Shanghai Jiao Tong University, Institute of Marine Equipment, Shanghai, China
| | - Lei S. Li
- Rice University, Department of Electrical and Computer Engineering, Houston, Texas, United States
| | - Jiamiao Yang
- Shanghai Jiao Tong University, School of Electronic Information and Electrical Engineering, Shanghai, China
- Shanghai Jiao Tong University, Institute of Marine Equipment, Shanghai, China
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9
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Blochet B, Akemann W, Gigan S, Bourdieu L. Fast wavefront shaping for two-photon brain imaging with multipatch correction. Proc Natl Acad Sci U S A 2023; 120:e2305593120. [PMID: 38100413 PMCID: PMC10743372 DOI: 10.1073/pnas.2305593120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 10/19/2023] [Indexed: 12/17/2023] Open
Abstract
Nonlinear fluorescence microscopy promotes in-vivo optical imaging of cellular structure at diffraction-limited resolution deep inside scattering biological tissues. Active compensation of tissue-induced aberrations and light scattering through adaptive wavefront correction further extends the accessible depth by restoring high resolution at large depth. However, those corrections are only valid over a very limited field of view within the angular memory effect. To overcome this limitation, we introduce an acousto-optic light modulation technique for fluorescence imaging with simultaneous wavefront correction at pixel scan speed. Biaxial wavefront corrections are first learned by adaptive optimization at multiple locations in the image field. During image acquisition, the learned corrections are then switched on the fly according to the position of the excitation focus during the raster scan. The proposed microscope is applied to in vivo transcranial neuron imaging and demonstrates multi-patch correction of thinned skull-induced aberrations and scattering at 40-kHz data acquisition speed.
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Affiliation(s)
- Baptiste Blochet
- Institut de Biologie de l’École Normale Supérieure, École Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres, Paris75005, France
- Laboratoire Kastler Brossel, École Normale Supérieure-Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Collège de France, Paris75005, France
| | - Walther Akemann
- Institut de Biologie de l’École Normale Supérieure, École Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres, Paris75005, France
- Laboratoire Kastler Brossel, École Normale Supérieure-Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Collège de France, Paris75005, France
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, École Normale Supérieure-Université Paris Sciences et Lettres, CNRS, Sorbonne Université, Collège de France, Paris75005, France
| | - Laurent Bourdieu
- Institut de Biologie de l’École Normale Supérieure, École Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres, Paris75005, France
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10
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Elias E, Sideris S, McDonnell C, Ellenbogen T. Generating Angular-Varying Time Delays of THz Pulses via Direct Space-to-Time Mapping of Metasurface Structures. ACS Appl Opt Mater 2023; 1:1783-1790. [PMID: 38037652 PMCID: PMC10683364 DOI: 10.1021/acsaom.3c00240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/20/2023] [Accepted: 09/29/2023] [Indexed: 12/02/2023]
Abstract
We experimentally demonstrate the generation of double terahertz (THz) pulses with tailored angular-dependent time delays from a nonlinear metasurface excited by a near-infrared femtosecond pulse. The tailored temporal properties of the generated pulses emerge from a direct mapping of the nonlinear spatial response of the metasurface to the emitted THz temporal profile. We utilize the Pancharatnam-Berry phase to implement symmetric and antisymmetric metasurface configurations and show that the emitted patterns present spatiotemporal "X-shaped" profiles after collimation by a parabolic mirror, with angular-dependent pulse delays corresponding to the intended design. In addition, we show that the addition of polarization multiplexing presents the opportunity to achieve a full range of elliptical THz polarizations. Double pulse generation and spatiotemporal shaping of THz waves in general show potential for THz spectroscopy and molecular dynamics applications, particularly in pump-probe experiments.
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Affiliation(s)
- Elazar Elias
- Raymond
and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 6779801, Israel
- Center
for Light-Matter Interaction, Tel-Aviv University, Tel Aviv 6779801, Israel
| | - Symeon Sideris
- Center
for Light-Matter Interaction, Tel-Aviv University, Tel Aviv 6779801, Israel
- Department
of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Cormac McDonnell
- Center
for Light-Matter Interaction, Tel-Aviv University, Tel Aviv 6779801, Israel
- Department
of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel Aviv 6997801, Israel
| | - Tal Ellenbogen
- Center
for Light-Matter Interaction, Tel-Aviv University, Tel Aviv 6779801, Israel
- Department
of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel Aviv 6997801, Israel
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11
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Fritzsche N, Ott F, Pink K, Kienle A. Focusing Coherent Light through Volume Scattering Phantoms via Wavefront Shaping. Sensors (Basel) 2023; 23:8397. [PMID: 37896491 PMCID: PMC10611003 DOI: 10.3390/s23208397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 10/29/2023]
Abstract
Manipulating the wavefront of coherent light incident on scattering media to enhance the imaging depth, sensitivity, and resolution is a common technique in biomedical applications. Local phase variations cause changes in the interference and can be used to create a focus inside or behind a scattering medium. We use wavefront shaping (WFS) to force constructive interference at an arbitrary location. The amount of light transmitted into a given region strongly depends on the scattering and absorption characteristics. These are described by their respective coefficients μs and μa and the scattering phase function. Controlling the scattering and absorption coefficients, we study the behavior of wavefront shaping and the achievable intensity enhancement behind volume scattering media with well-defined optical properties. The phantoms designed in this publication are made of epoxy resin. Into these epoxy matrices, specific amounts of scattering and absorbing particles, such as titanium dioxide pigments and molecular dyes, are mixed. The mixture obtained is filled into 3D-printed frames of various thicknesses. After a precise fabrication procedure, an integrating sphere-based setup characterizes the phantoms experimentally. It detects the total hemispherical transmission and reflection. Further theoretical characterization is performed with a newly developed hybrid PN method. This method senses the flux of light into a particular angular range at the lower boundary of a slab. The calculations are performed without suffering from ringing and fulfill the exact boundary conditions there. A decoupled two-path detection system allows for fast optimization as well as sensitive detection. The measurements yield results that agree well with the theoretically expected behavior.
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Affiliation(s)
- Niklas Fritzsche
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, D-89081 Ulm, Germany
- Faculty of Natural Sciences, Ulm University, D-89081 Ulm, Germany
| | - Felix Ott
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, D-89081 Ulm, Germany
- Faculty of Natural Sciences, Ulm University, D-89081 Ulm, Germany
| | - Karsten Pink
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, D-89081 Ulm, Germany
- Faculty of Natural Sciences, Ulm University, D-89081 Ulm, Germany
| | - Alwin Kienle
- Institut für Lasertechnologien in der Medizin und Meßtechnik an der Universität Ulm, D-89081 Ulm, Germany
- Faculty of Natural Sciences, Ulm University, D-89081 Ulm, Germany
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12
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Zhang Q, Charania S, Rothe S, Koukourakis N, Neumann N, Plettemeier D, Czarske JW. Multimode Optical Interconnects on Silicon Interposer Enable Confidential Hardware-to-Hardware Communication. Sensors (Basel) 2023; 23:6076. [PMID: 37447925 DOI: 10.3390/s23136076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/25/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Following Moore's law, the density of integrated circuits is increasing in all dimensions, for instance, in 3D stacked chip networks. Amongst other electro-optic solutions, multimode optical interconnects on a silicon interposer promise to enable high throughput for modern hardware platforms in a restricted space. Such integrated architectures require confidential communication between multiple chips as a key factor for high-performance infrastructures in the 5G era and beyond. Physical layer security is an approach providing information theoretic security among network participants, exploiting the uniqueness of the data channel. We experimentally project orthogonal and non-orthogonal symbols through 380 μm long multimode on-chip interconnects by wavefront shaping. These interconnects are investigated for their uniqueness by repeating these experiments across multiple channels and samples. We show that the detected speckle patterns resulting from modal crosstalk can be recognized by training a deep neural network, which is used to transform these patterns into a corresponding readable output. The results showcase the feasibility of applying physical layer security to multimode interconnects on silicon interposers for confidential optical 3D chip networks.
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Affiliation(s)
- Qian Zhang
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
| | - Sujay Charania
- Chair of Radio Frequency and Photonics Engineering, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
| | - Stefan Rothe
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
| | - Nektarios Koukourakis
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
| | - Niels Neumann
- Institute for Electrical Information Technology, TU Clausthal, 38678 Clausthal-Zellerfeld, Germany
| | - Dirk Plettemeier
- Chair of Radio Frequency and Photonics Engineering, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
| | - Juergen W Czarske
- Laboratory of Measurement and Sensor System Technique, Faculty of Electrical and Computer Engineering, TU Dresden, 01069 Dresden, Germany
- Institute of Applied Physics, School of Science, TU Dresden, 01069 Dresden, Germany
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13
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Wang T, Rumman N, Bassène P, N'Gom M. Scoring-Based Genetic Algorithm for Wavefront Shaping to Optimize Multiple Objectives. J Imaging 2023; 9. [PMID: 36826968 DOI: 10.3390/jimaging9020049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 02/13/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
We present a scoring-based genetic algorithm (SBGA) for wavefront shaping to optimize multiple objectives at a time. The algorithm is able to find one feasible solution despite having to optimize multiple objectives. We employ the algorithm to generate multiple focus points simultaneously and allocate their intensities as desired. We then introduce a third objective to confine light focusing only to desired targets and prevent irradiation in neighboring regions. Through simulations and experiments, we demonstrate the algorithm's ease of implementation and flexibility to control the search direction. This algorithm can potentially be applied to improve biomedical imaging, optogenetics, and optical trapping.
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14
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Ji R, Guo X, Liu Z, Wu X, Jin C, Liu F, Zheng X, Sun Y, Wang S. A Single-Celled Metasurface for Multipolarization Generation and Wavefront Manipulation. Nanomaterials (Basel) 2022; 12:4336. [PMID: 36500959 PMCID: PMC9740456 DOI: 10.3390/nano12234336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 11/23/2022] [Accepted: 12/02/2022] [Indexed: 06/17/2023]
Abstract
Due to their unprecedented ability to flexibly manipulate the parameters of light, metasurfaces offer a new approach to integrating multiple functions in a single optical element. In this paper, based on a single-celled metasurface composed of chiral umbrella-shaped metal-insulator-metal (MIM) unit cells, a strategy for simultaneous multiple polarization generation and wavefront shaping is proposed. The unit cells can function as broadband and high-performance polarization-preserving mirrors. In addition, by introducing a chiral-assisted Aharonov-Anandan (AA) geometric phase, the phase profile and phase retardation of two spin-flipped orthogonal circular polarized components can be realized simultaneously and independently with a single-celled metasurface via two irrelevant parameters. Benefiting from this flexible phase manipulation ability, a vectorial hologram generator and metalens array with spatially varying polarizations were demonstrated. This work provides an effective approach to avoid the pixel and efficiency losses caused by the intrinsic symmetry of the PB geometric phase, and it may play an important role in the miniaturization and integration of multipolarization-involved displays, real-time imaging, and spectroscopy systems.
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Affiliation(s)
- Ruonan Ji
- School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Xin Guo
- Science and Technology on Low-Light-Level Night Version Laboratory, Xi’an 710065, China
| | - Zhichao Liu
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics of CAS, Xi’an 710119, China
| | - Xianfeng Wu
- School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Chuan Jin
- State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics of CAS, Xi’an 710119, China
| | - Feng Liu
- School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Xinru Zheng
- School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Yang Sun
- School of Physical Science and Technology, Northwestern Polytechnical University, Xi’an 710129, China
| | - Shaowei Wang
- State Key Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083, China
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15
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Bender N, Goetschy A, Hsu CW, Yilmaz H, Palacios PJ, Yamilov A, Cao H. Coherent enhancement of optical remission in diffusive media. Proc Natl Acad Sci U S A 2022; 119:e2207089119. [PMID: 36191199 DOI: 10.1073/pnas.2207089119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Remitted waves are used for sensing and imaging in diverse diffusive media from the Earth's crust to the human brain. Separating the source and detector increases the penetration depth of light, but the signal strength decreases rapidly, leading to a poor signal-to-noise ratio. Here, we show, experimentally and numerically, that wavefront shaping a laser beam incident on a diffusive sample enables an enhancement of remission by an order of magnitude at depths of up to 10 transport mean free paths. We develop a theoretical model which predicts the maximal remission enhancement. Our analysis reveals a significant improvement in the sensitivity of remitted waves to local changes of absorption deep inside diffusive media. This work illustrates the potential of coherent wavefront control for noninvasive diffuse wave imaging applications, such as diffuse optical tomography and functional near-infrared spectroscopy.
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16
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Karnieli A, Roitman D, Liebtrau M, Tsesses S, Van Nielen N, Kaminer I, Arie A, Polman A. Cylindrical Metalens for Generation and Focusing of Free-Electron Radiation. Nano Lett 2022; 22:5641-5650. [PMID: 35791573 PMCID: PMC9335868 DOI: 10.1021/acs.nanolett.1c04556] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Metasurfaces constitute a powerful approach to generate and control light by engineering optical material properties at the subwavelength scale. Recently, this concept was applied to manipulate free-electron radiation phenomena, rendering versatile light sources with unique functionalities. In this Letter, we experimentally demonstrate spectral and angular control over coherent light emission by metasurfaces that interact with free-electrons under grazing incidence. Specifically, we study metalenses based on chirped metagratings that simultaneously emit and shape Smith-Purcell radiation in the visible and near-infrared spectral regime. In good agreement with theory, we observe the far-field signatures of strongly convergent and divergent cylindrical radiation wavefronts using in situ hyperspectral angle-resolved light detection in a scanning electron microscope. Furthermore, we theoretically explore simultaneous control over the polarization and wavefront of Smith-Purcell radiation via a split-ring-resonator metasurface, enabling tunable operation by spatially selective mode excitation at nanometer resolution. Our work highlights the potential of merging metasurfaces with free-electron excitations for versatile and highly tunable radiation sources in wide-ranging spectral regimes.
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Affiliation(s)
- Aviv Karnieli
- Raymond
and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Dolev Roitman
- Raymond
and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
| | - Matthias Liebtrau
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Shai Tsesses
- Andrew
and Erna Viterbi Department of Electrical Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Nika Van Nielen
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Ido Kaminer
- Andrew
and Erna Viterbi Department of Electrical Engineering, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Ady Arie
- School
of Electrical Engineering, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Albert Polman
- Center
for Nanophotonics, NWO-Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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17
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Junge S, Schmieder F, Sasse P, Czarske J, Torres-Mapa ML, Heisterkamp A. Holographic optogenetic stimulation with calcium imaging as an all optical tool for cardiac electrophysiology. J Biophotonics 2022; 15:e202100352. [PMID: 35397155 DOI: 10.1002/jbio.202100352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 02/25/2022] [Accepted: 04/06/2022] [Indexed: 06/14/2023]
Abstract
All optical approaches to control and read out the electrical activity in a cardiac syncytium can improve our understanding of cardiac electrophysiology. Here, we demonstrate optogenetic stimulation of cardiomyocytes with high spatial precision using light foci generated with a ferroelectric spatial light modulator. Computer generated holograms binarized by bidirectional error diffusion create multiple foci with more even intensity distribution compared with thresholding approach. We evoke the electrical activity of cardiac HL1 cells expressing the channelrhodopsin-2 variant, ChR2(H134R) using single and multiple light foci and at the same time visualize the action potential using a calcium sensitive indicator called Cal-630. We show that localized regions in the cardiac monolayer can be stimulated enabling us to initiate signal propagation from a precise location. Furthermore, we demonstrate that probing the cardiac cells with multiple light foci enhances the excitability of the cardiac network. This approach opens new applications in manipulating and visualizing the electrical activity in a cardiac syncytium.
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Affiliation(s)
- Sebastian Junge
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Felix Schmieder
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
| | - Philipp Sasse
- Medical Faculty, Institute of Physiology I, University of Bonn, Bonn, Germany
| | - Jürgen Czarske
- Faculty of Electrical and Computer Engineering, Laboratory of Measurement and Sensor System Technique and Competence Center Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Dresden, Germany
- Faculty of Physics, School of Science and Excellence Cluster Physics of Life, TU Dresden, Dresden, Germany
| | - Maria Leilani Torres-Mapa
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
| | - Alexander Heisterkamp
- Institute of Quantum Optics, Gottfried Wilhelm Leibniz University, Hannover, Germany
- Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hannover, Germany
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18
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Gundersen KG, Potvin R. Clinical Outcomes and Quality of Vision Associated with Bilateral Implantation of a Wavefront Shaping Presbyopia Correcting Intraocular Lens. Clin Ophthalmol 2022; 15:4723-4730. [PMID: 34983995 PMCID: PMC8699763 DOI: 10.2147/opth.s342947] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/10/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose To provide normative visual acuity and quality of vision data related to bilateral implantation of a wavefront shaping presbyopia correcting intraocular lens (IOL). Patients and Methods This was a non-interventional research study of the refraction, visual acuity (VA) and quality of vision achieved after bilateral implantation of a wavefront shaping presbyopia correcting intraocular lens between 3 months and 12 months post-surgery. The manifest refraction, and uncorrected and distance corrected VA at near, intermediate and distance (40 cm, 50 cm, 66cm, 4 m) were tested. Binocular mesopic VA at 4m and uncorrected photopic low contrast (25%) VA at 4 m were also tested, the latter with and without a glare source. A patient reported outcome questionnaire was administered. Defocus curve testing with and without simulated myopia in the non-dominant eye was also tested (reported elsewhere). Results Forty subjects completed the study. There was no statistically significant difference between the uncorrected and distance corrected VA at any distance. Mean logMAR binocular VAs were (−0.07 ± 0.07) at 4 m, (0.00 ± 0.07) at 66 cm and (0.07 ± 0.11) at 40 cm. Uncorrected photopic low contrast VA was statistically significantly better without glare (0.09 ± 0.10) compared to with glare (0.44 ± 0.21, p < 0.01). Reported glare, halos and starbursts were “not at all” Or “a little” bothersome for more than 95% of subjects. Hazy vision and blurred vision were reported most often. Conclusion The Vivity IOL provided patients with good distance and intermediate vision, and functional near vision with low reported bother from glare, halos, or starbursts. ![]()
Point your SmartPhone at the code above. If you have a QR code reader the video abstract will appear. Or use: https://youtu.be/fCukWtZz0pk
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19
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Liu G, Kang JW, Jonas O. Long-GRIN-Lens Microendoscopy Enabled by Wavefront Shaping for a Biomedical Microdevice: An Analytical Investigation. Materials (Basel) 2021; 14:3392. [PMID: 34207445 DOI: 10.3390/ma14123392] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 06/08/2021] [Accepted: 06/15/2021] [Indexed: 12/20/2022]
Abstract
We analytically investigate the feasibility of long graded-index (GRIN)-lens-based microendoscopes through wavefront shaping. Following the very well-defined ray trajectories in a GRIN lens, mode-dependent phase delay is first determined. Then, the phase compensation needed for obtaining diffraction limited resolution is derived. Finally, the diffraction pattern of the lens output is computed using the Rayleigh–Sommerfeld diffraction theory. We show that diffraction-limited resolution is obtained for a 0.5 mm diameter lens with a length over 1 m. It is also demonstrated that different imaging working distances (WDs) can be realized by modifying the phase compensation. When a short design WD is used, a large imaging numerical aperture (NA) higher than 0.4 is achievable even when a low NA lens (NA = 0.1) is used. The long- and thin-GRIN-lens-based microendoscope investigated here, which is attractive for biomedical applications, is being prioritized for use in a clinical stage microdevice that measures three-dimensional drug responses inside the body. The advance described in this work may enable superior imaging capabilities in clinical applications in which long and flexible imaging probes are favored.
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20
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Singh S, Labouesse S, Piestun R. Tunable mode control through myriad-mode fibers. J Lightwave Technol 2021; 39:2961-2970. [PMID: 33994658 PMCID: PMC8117977 DOI: 10.1109/jlt.2021.3057615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Multimode fibers are attractive for imaging, communication, computation, and energy delivery. Unfortunately, intermodal and polarization coupling precludes direct control of the delivered mode composition. We present a technique to tailor the mode composition at the output of a multimode fiber with thousands of modes, which we refer to as myriad-mode fiber, using its experimentally measured transmission matrix. While precise mode control has been demonstrated in typical multimode fibers with up to 210 modes, the method proposed here is particularly useful for high mode number fibers, such as when the number of modes is comparable to the number of modes of the wavefront shaping spatial light modulator. To illustrate the technique, we select different subsets of modes to create focal spots at the output of a fiber with 7140 modes. Importantly, we define efficiency and fidelity metrics to evaluate the mode control and demonstrate the relationship between efficiency, fidelity, and the spatial location of the spots across the distal fiber cross-section.
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Affiliation(s)
- Sakshi Singh
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Colorado 80309, USA
| | - Simon Labouesse
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Colorado 80309, USA
| | - Rafael Piestun
- Department of Electrical, Computer, and Energy Engineering, University of Colorado Boulder, Colorado 80309, USA
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21
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Dauderstädt U, Dürr P, Gehner A, Wagner M, Schenk H. Analog Spatial Light Modulators Based on Micromirror Arrays. Micromachines (Basel) 2021; 12:mi12050483. [PMID: 33922590 PMCID: PMC8145509 DOI: 10.3390/mi12050483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/31/2021] [Accepted: 04/15/2021] [Indexed: 11/21/2022]
Abstract
The Fraunhofer Institute for Photonic Microsystems (IPMS) has been developing and manufacturing micromirror arrays for more than 20 years. While originally focusing on applications related to microlithography and therefore mainly for light in the deep ultraviolet range, the range of applications has been expanded since, including applications in the visible and near-infrared range. This paper gives an overview of the devices and their designs, fabrication, and characterization.
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Affiliation(s)
- Ulrike Dauderstädt
- Fraunhofer IPMS, Maria-Reiche-Straße 2, 01109 Dresden, Germany; (P.D.); (A.G.); (M.W.); (H.S.)
- Correspondence:
| | - Peter Dürr
- Fraunhofer IPMS, Maria-Reiche-Straße 2, 01109 Dresden, Germany; (P.D.); (A.G.); (M.W.); (H.S.)
| | - Andreas Gehner
- Fraunhofer IPMS, Maria-Reiche-Straße 2, 01109 Dresden, Germany; (P.D.); (A.G.); (M.W.); (H.S.)
| | - Michael Wagner
- Fraunhofer IPMS, Maria-Reiche-Straße 2, 01109 Dresden, Germany; (P.D.); (A.G.); (M.W.); (H.S.)
| | - Harald Schenk
- Fraunhofer IPMS, Maria-Reiche-Straße 2, 01109 Dresden, Germany; (P.D.); (A.G.); (M.W.); (H.S.)
- Chair of Micro and Nano Systems, Brandenburgische Technische Universität Cottbus-Senftenberg, Konrad-Zuse-Straße 1, 03046 Cottbus, Germany
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22
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Tehrani KF, Koukourakis N, Czarske J, Mortensen LJ. In situ measurement of the isoplanatic patch for imaging through intact bone. J Biophotonics 2021; 14:e202000160. [PMID: 32844561 PMCID: PMC10599401 DOI: 10.1002/jbio.202000160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/23/2020] [Accepted: 08/24/2020] [Indexed: 06/11/2023]
Abstract
Wavefront-shaping (WS) enables imaging through scattering tissues like bone, which is important for neuroscience and bone-regeneration research. WS corrects for the optical aberrations at a given depth and field-of-view (FOV) within the sample; the extent of the validity of which is limited to a region known as the isoplanatic patch (IP). Knowing this parameter helps to estimate the number of corrections needed for WS imaging over a given FOV. In this paper, we first present direct transmissive measurement of murine skull IP using digital optical phase conjugation based focusing. Second, we extend our previously reported phase accumulation ray tracing (PART) method to provide in-situ in-silico estimation of IP, called correlative PART (cPART). Our results show an IP range of 1 to 3 μm for mice within an age range of 8 to 14 days old and 1.00 ± 0.25 μm in a 12-week old adult skull. Consistency between the two measurement approaches indicates that cPART can be used to approximate the IP before a WS experiment, which can be used to calculate the number of corrections required within a given field of view.
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Affiliation(s)
- Kayvan Forouhesh Tehrani
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA, 30602, USA
| | - Nektarios Koukourakis
- TU Dresden, Chair of Measurement and Sensor System Technique, Helmholtzstr. 18, 01062 Dresden, Germany
- Competence Center for Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Germany
| | - Jürgen Czarske
- TU Dresden, Chair of Measurement and Sensor System Technique, Helmholtzstr. 18, 01062 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Germany
- Competence Center for Biomedical Computational Laser Systems (BIOLAS), TU Dresden, Germany
| | - Luke J Mortensen
- Regenerative Bioscience Center, Rhodes Center for ADS, University of Georgia, Athens, GA, 30602, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA
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23
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Kanngiesser J, Roth B. Wavefront Shaping Concepts for Application in Optical Coherence Tomography-A Review. Sensors (Basel) 2020; 20:E7044. [PMID: 33316998 PMCID: PMC7763956 DOI: 10.3390/s20247044] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 01/10/2023]
Abstract
Optical coherence tomography (OCT) enables three-dimensional imaging with resolution on the micrometer scale. The technique relies on the time-of-flight gated detection of light scattered from a sample and has received enormous interest in applications as versatile as non-destructive testing, metrology and non-invasive medical diagnostics. However, in strongly scattering media such as biological tissue, the penetration depth and imaging resolution are limited. Combining OCT imaging with wavefront shaping approaches significantly leverages the capabilities of the technique by controlling the scattered light field through manipulation of the field incident on the sample. This article reviews the main concepts developed so far in the field and discusses the latest results achieved with a focus on signal enhancement and imaging.
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Affiliation(s)
- Jonas Kanngiesser
- Hannoversches Zentrum für Optische Technologien, Leibniz Universität Hannover, Nienburger Straße 17, D-30167 Hannover, Germany;
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering–Innovation Across Disciplines), D-30167 Hannover, Germany
| | - Bernhard Roth
- Hannoversches Zentrum für Optische Technologien, Leibniz Universität Hannover, Nienburger Straße 17, D-30167 Hannover, Germany;
- Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering–Innovation Across Disciplines), D-30167 Hannover, Germany
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24
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Park JH, Park J, Lee K, Park Y. Disordered Optics: Exploiting Multiple Light Scattering and Wavefront Shaping for Nonconventional Optical Elements. Adv Mater 2020; 32:e1903457. [PMID: 31553491 DOI: 10.1002/adma.201903457] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/17/2019] [Indexed: 06/10/2023]
Abstract
Advances in diverse areas such as inspection, imaging, manufacturing, telecommunications, and information processing have been stimulated by novel optical devices. Conventional material ingredients for these devices are typically made of homogeneous refractive or diffractive materials and require sophisticated design and fabrication, which results in practical limitations related to their form and functional figures of merit. To overcome such limitations, recent developments in the application of disordered materials as novel optical elements have indicated great potential in enabling functionalities that go beyond their conventional counterparts, while the materials exhibit potential advantages with respect to reduced form factors. Combined with wavefront shaping, disordered materials enable dynamic transitions between multiple functionalities in a single active optical device. Recent progress in this field is summarized to gain insight into the physical principles behind disordered optics with regard to their advantages in various applications as well as their limitations compared to conventional optics.
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Affiliation(s)
- Jung-Hoon Park
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jongchan Park
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141, Republic of Korea
| | - KyeoReh Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141, Republic of Korea
| | - YongKeun Park
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- KAIST Institute for Health Science and Technology, KAIST, Daejeon, 34141, Republic of Korea
- Tomocube Inc., Daejeon, 34109, Republic of Korea
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25
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del Hougne P, Imani MF, Diebold AV, Horstmeyer R, Smith DR. Learned Integrated Sensing Pipeline: Reconfigurable Metasurface Transceivers as Trainable Physical Layer in an Artificial Neural Network. Adv Sci (Weinh) 2020; 7:1901913. [PMID: 32042558 PMCID: PMC7001623 DOI: 10.1002/advs.201901913] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/26/2019] [Indexed: 05/18/2023]
Abstract
The rapid proliferation of intelligent systems (e.g., fully autonomous vehicles) in today's society relies on sensors with low latency and computational effort. Yet current sensing systems ignore most available a priori knowledge, notably in the design of the hardware level, such that they fail to extract as much task-relevant information per measurement as possible. Here, a "learned integrated sensing pipeline" (LISP), including in an end-to-end fashion both physical and processing layers, is shown to enable joint learning of optimal measurement strategies and a matching processing algorithm, making use of a priori knowledge on task, scene, and measurement constraints. Numerical results demonstrate accuracy improvements around 15% for object recognition tasks with limited numbers of measurements, using dynamic metasurface apertures capable of transceiving programmable microwave patterns. Moreover, it is concluded that the optimal learned microwave patterns are nonintuitive, underlining the importance of the LISP paradigm in current sensorization trends.
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Affiliation(s)
- Philipp del Hougne
- Institut de Physique de NiceCNRS UMR 7010Université Côte d'AzurNice06108France
| | - Mohammadreza F. Imani
- Center for Metamaterials and Integrated PlasmonicsDepartment of Electrical and Computer EngineeringDuke UniversityDurhamNC27708USA
| | - Aaron V. Diebold
- Center for Metamaterials and Integrated PlasmonicsDepartment of Electrical and Computer EngineeringDuke UniversityDurhamNC27708USA
| | | | - David R. Smith
- Center for Metamaterials and Integrated PlasmonicsDepartment of Electrical and Computer EngineeringDuke UniversityDurhamNC27708USA
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26
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Jiang ZH, Kang L, Yue T, Xu HX, Yang Y, Jin Z, Yu C, Hong W, Werner DH, Qiu CW. A Single Noninterleaved Metasurface for High-Capacity and Flexible Mode Multiplexing of Higher-Order Poincaré Sphere Beams. Adv Mater 2020; 32:e1903983. [PMID: 31879999 DOI: 10.1002/adma.201903983] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 10/21/2019] [Indexed: 06/10/2023]
Abstract
Cylindrical vector vortex beams, a particular class of higher-order Poincaré sphere beams, are generalized forms of waves carrying orbital angular momentum with inhomogeneous states-of-polarization on their wavefronts. Conventional methods as well as the more recently proposed segmented/interleaved shared-aperture metasurfaces for vortex beam generation are either severely limited by bulky optical setups or by restricted channel capacity with low efficiency and mode number. Here, a noninterleaved vortex multiplexing approach is proposed, which utilizes superimposed scattered waves with opposite spin states emanating from all meta-atoms in a coherent manner, counter-intuitively enabling ultrahigh-capacity, high-efficiency, and flexible generation of massive vortex beams with structured state-of-polarization. A series of exemplary prototypes, implemented by sub-wavelength-thick metasurfaces, are demonstrated experimentally, achieving kaleidoscopic vector vortex beams. This methodology holds great promise for structured wavefront shaping, vortex generation, and high information-capacity planar photonics, which may have a profound impact on transformative technological advances in fields including spin-Hall photonics, optical holography, compressive imaging, electromagnetic communication, and so on.
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Affiliation(s)
- Zhi Hao Jiang
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Lei Kang
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Taiwei Yue
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - He-Xiu Xu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Yuanjie Yang
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
- School of Physics, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Zhongwei Jin
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Changyuan Yu
- Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Wei Hong
- State Key Laboratory of Millimeter Waves, School of Information Science and Engineering, Southeast University, Nanjing, 210096, China
| | - Douglas H Werner
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
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27
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Hu L, Hu S, Li Y, Gong W, Si K. Reliability of wavefront shaping based on coherent optical adaptive technique in deep tissue focusing. J Biophotonics 2020; 13:e201900245. [PMID: 31622537 DOI: 10.1002/jbio.201900245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 09/12/2019] [Accepted: 10/16/2019] [Indexed: 06/10/2023]
Abstract
Wavefront shaping can compensate the wavefront distortions in deep tissue focusing, leading to an improved penetration depth. However, when using the backscattered signals as the feedback, unexpected compensation bias may be introduced, resulting in focusing position deviations or even no focus in the illumination focal plane. Here we investigated the reliability of wavefront shaping based on coherent optical adaptive technique in deep tissue focusing by measuring the position deviations between the foci in the illumination focal plane and the epi-detection plane. The experimental results show that when the penetration depth reaches 150 μm in mouse brain tissue (with scattering coefficient ~22.42 mm-1 ) using a 488 nm laser and an objective lens with 0.75 numerical aperture, the center of the real focus will deviate out of one radius range of the Airy disk while the optimized focus in the epi-detection plane maintained basically at the center. With the penetration depth increases, the peak to background ratio of the focus in the illumination focal plane decreases faster than that in the epi-detection plane. The results indicate that when the penetration depth reaches 150 μm, feedback based on backscattered signals will make wavefront shaping lose its reliability, which may provide a guidance for applications of non-invasive precise optogenetics or deep tissue optical stimulation using wavefront shaping methods. A, Intensity distribution in the epi-detection plane and the illumination focal plane before and after correction, corresponding to brain sections with 250 and 300 μm thickness, respectively. Scale bar is 2 μm. B, Averaged focusing deviations in the epi-detection plane (optimized) and the illumination focal plane (monitored) after compensation. The unit of the ordinate is one Airy disk diameter. Black dashed line represents one Airy disk radius. Bars represent the SE of each measurement set.
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Affiliation(s)
- Lejia Hu
- State Key Laboratory of Modern Optical Instrumentation, Department of Neurobiology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- College of Optical Science and Engineering, Zhejiang University, Hangzhou, China
| | - Shuwen Hu
- College of Optical Science and Engineering, Zhejiang University, Hangzhou, China
| | - Younong Li
- Centre for Neuroscience, Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Gong
- Centre for Neuroscience, Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Ke Si
- State Key Laboratory of Modern Optical Instrumentation, Department of Neurobiology of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- College of Optical Science and Engineering, Zhejiang University, Hangzhou, China
- Centre for Neuroscience, Department of Neurobiology, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
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28
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Abstract
Electronic matter waves traveling through the weak and smoothly varying disorder potential of a semiconductor show a characteristic branching behavior instead of a smooth spreading of flow. By transferring this phenomenon to optics, we demonstrate numerically how the branched flow of light can be controlled to propagate along a single branch rather than along many of them at the same time. Our method is based on shaping the incoming wavefront and only requires partial knowledge of the system's transmission matrix. We show that the light flowing along a single branch has a broadband frequency stability such that one can even steer pulses along selected branches-a prospect with many interesting possibilities for wave control in disordered environments.
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29
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Maddipatla R, Cervantes J, Otani Y, Cense B. Retinal imaging with optical coherence tomography and low-loss adaptive optics using a 2.8-mm beam size. J Biophotonics 2019; 12:e201800192. [PMID: 30328279 DOI: 10.1002/jbio.201800192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 09/24/2018] [Accepted: 10/11/2018] [Indexed: 05/02/2023]
Abstract
As data acquisition for retinal imaging with optical coherence tomography (OCT) becomes faster, efficient collection of photons becomes more important to maintain image quality. One approach is to use a larger aperture at the eye's pupil to collect more photons that have been reflected from the retina. A 2.8-mm beam diameter system with only seven reflecting surfaces was developed for low-loss retinal imaging. The larger beam size requires defocus and astigmatism correction, which was done in a closed loop adaptive optics method using a Shack-Hartmann wavefront sensor and a deformable mirror (DM) with 140 actuators and a ±2.75 μm stroke. This DM facilitates defocus correction ranging from approximately -3 D to +3 D. Comparing the new system with a standard 1.2-mm system on a model eye, a signal-to-noise gain of 4.5 dB and a 2.3 times smaller speckle size were measured. Measurements on the retinas of five subjects showed even better results, with increases in dynamic range up to 13 dB. Note that the new sample arm only occupies 30 cm × 60 cm, which makes it highly suitable for imaging in a clinical environment. Figure: B-scan images obtained over a width of 8 deg from the right eye of a 31-year-old Caucasian male. While the left side was imaged with a standard 1.2-mm OCT system, the right side was imaged with the 2.8-mm system. Both images were collected with the same integration time and incident power, after correction of aberrations. Using the dynamic range within the images, which is determined by comparing the highest pixel value to the noise floor, a difference in dynamic range of 10.8 dB was measured between the two systems.
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Affiliation(s)
- Reddikumar Maddipatla
- Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
- School of Optometry, Indiana University, Bloomington, Indiana
| | - Joel Cervantes
- Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
- Centro Universitario de Ciencias Exactas e Ingenierías (CUCEI), Universidad de Guadalajara, Guadalajara, Jal, Mexico
| | - Yukitoshi Otani
- Center for Optical Research and Education, Utsunomiya University, Utsunomiya, Japan
- Department of Optical Engineering, Utsunomiya University, Tochigi, Japan
| | - Barry Cense
- Optical+Biomedical Engineering Laboratory, Department of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, Western Australia, Australia
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30
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Abstract
To capture the emergent properties of neural circuits, high-speed volumetric imaging of neural activity at cellular resolution is needed. Here, we introduce wavelength multiplexing to perform fast volumetric two-photon imaging of cortical columns (>2,000 neurons in 10 planes at 10 vol/s), using two different calcium indicators, an electrically tunable lens and a spatial light modulator. We image the activity of neuronal populations from layers 2/3 to 5 of primary visual cortex from awake mice, finding a lack of columnar structures in orientation responses and revealing correlations between layers which differ from trial to trial. We also simultaneously image functional correlations between presynaptic layer 1 axons and postsynaptic layer 2/3 neurons. Wavelength multiplexing enhances high-speed volumetric microscopy and can be combined with other optical multiplexing methods to easily boost imaging throughput.
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Affiliation(s)
- Shuting Han
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Weijian Yang
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Rafael Yuste
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027, USA
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31
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Cheng J, Fan F, Chang S. Recent Progress on Graphene-Functionalized Metasurfaces for Tunable Phase and Polarization Control. Nanomaterials (Basel) 2019; 9:E398. [PMID: 30857236 PMCID: PMC6473956 DOI: 10.3390/nano9030398] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/16/2019] [Accepted: 02/17/2019] [Indexed: 11/16/2022]
Abstract
The combination of graphene and a metasurface holds great promise for dynamic manipulation of the electromagnetic wave from low terahertz to mid-infrared. The optical response of graphene is significantly enhanced by the highly-localized fields in the meta-atoms, and the characteristics of meta-atoms can in turn be modulated in a large dynamic range through electrical doping of graphene. Graphene metasurfaces are initially focused on intensity modulation as modulators and tunable absorbers. In this paper, we review the recent progress of graphene metasurfaces for active control of the phase and the polarization. The related applications involve, but are not limited to lenses with tunable intensity or focal length, dynamic beam scanning, wave plates with tunable frequency, switchable polarizers, and real-time generation of an arbitrary polarization state, all by tuning the gate voltage of graphene. The review is concluded with a discussion of the existing challenges and the personal perspective of future directions.
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Affiliation(s)
- Jierong Cheng
- Institute of Modern Optics, Nankai University, Tianjin 300350, China.
| | - Fei Fan
- Institute of Modern Optics, Nankai University, Tianjin 300350, China.
| | - Shengjiang Chang
- Institute of Modern Optics, Nankai University, Tianjin 300350, China.
- Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Tianjin 300350, China.
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32
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Hemphill AS, Shen Y, Hwang J, Wang LV. High-speed alignment optimization of digital optical phase conjugation systems based on autocovariance analysis in conjunction with orthonormal rectangular polynomials. J Biomed Opt 2018; 24:1-11. [PMID: 30156064 PMCID: PMC6444113 DOI: 10.1117/1.jbo.24.3.031004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 08/06/2018] [Indexed: 05/23/2023]
Abstract
Digital optical phase conjugation (DOPC) enables many optical applications by permitting focusing of light through scattering media. However, DOPC systems require precise alignment of all optical components, particularly of the spatial light modulator (SLM) and camera, in order to accurately record the wavefront and perform playback through the use of time-reversal symmetry. We present a digital compensation technique to optimize the alignment of the SLM in five degrees of freedom, permitting focusing through thick scattering media with a thickness of 5 mm and transport scattering coefficient of 2.5 mm - 1 while simultaneously improving focal quality, as quantified by the peak-to-background ratio, by several orders of magnitude over an unoptimized alignment.
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Affiliation(s)
- Ashton S. Hemphill
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
- California Institute of Technology, Caltech Optical Imaging Laboratory, Department of Electrical Engineering, Pasadena, California, United States
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, St. Louis, Missouri, United States
| | - Yuecheng Shen
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
- California Institute of Technology, Caltech Optical Imaging Laboratory, Department of Electrical Engineering, Pasadena, California, United States
| | - Jeeseong Hwang
- National Institute of Standards and Technology, Quantum Electromagnetics Division, Boulder, Colorado, United States
| | - Lihong V. Wang
- California Institute of Technology, Caltech Optical Imaging Laboratory, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
- California Institute of Technology, Caltech Optical Imaging Laboratory, Department of Electrical Engineering, Pasadena, California, United States
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33
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Abstract
Wavefront shaping with spatial light modulators has recently motivated many studies in the field of light manipulation in diffusive media. Here, we extend this concept to acoustic waves by designing and building a binary phase-modulating spatial sound modulator (SSM). The SSM is an acoustic metasurface consisting of unit cells with two states, switchable through programmed electronics. We demonstrate in audible frequencies, and in a reverberating environment, the capability of controlling and reshaping any complex sound field. Our work will not only open avenues to study wave propagation in complex and chaotic media but also inspire applications in acoustic engineering. A reverberating environment is a common complex medium for airborne sound, with familiar examples such as music halls and lecture theaters. The complexity of reverberating sound fields has hindered their meaningful control. Here, by combining acoustic metasurface and adaptive wavefield shaping, we demonstrate the versatile control of reverberating sound fields in a room. This is achieved through the design and the realization of a binary phase-modulating spatial sound modulator that is based on an actively reconfigurable acoustic metasurface. We demonstrate useful functionalities including the creation of quiet zones and hotspots in a typical reverberating environment.
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34
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Liu Y, Shen Y, Ruan H, Brodie FL, Wong TTW, Yang C, Wang LV. Time-reversed ultrasonically encoded optical focusing through highly scattering ex vivo human cataractous lenses. J Biomed Opt 2018; 23:1-4. [PMID: 29322749 PMCID: PMC5762002 DOI: 10.1117/1.jbo.23.1.010501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/01/2017] [Indexed: 06/07/2023]
Abstract
Normal development of the visual system in infants relies on clear images being projected onto the retina, which can be disrupted by lens opacity caused by congenital cataract. This disruption, if uncorrected in early life, results in amblyopia (permanently decreased vision even after removal of the cataract). Doctors are able to prevent amblyopia by removing the cataract during the first several weeks of life, but this surgery risks a host of complications, which can be equally visually disabling. Here, we investigated the feasibility of focusing light noninvasively through highly scattering cataractous lenses to stimulate the retina, thereby preventing amblyopia. This approach would allow the cataractous lens removal surgery to be delayed and hence greatly reduce the risk of complications from early surgery. Employing a wavefront shaping technique named time-reversed ultrasonically encoded optical focusing in reflection mode, we focused 532-nm light through a highly scattering ex vivo adult human cataractous lens. This work demonstrates a potential clinical application of wavefront shaping techniques.
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Affiliation(s)
- Yan Liu
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Yuecheng Shen
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
| | - Haowen Ruan
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
| | - Frank L. Brodie
- University of California, San Francisco, Department of Ophthalmology, San Francisco, California, United States
| | - Terence T. W. Wong
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
| | - Changhuei Yang
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
| | - Lihong V. Wang
- California Institute of Technology, Department of Electrical Engineering, Pasadena, California, United States
- California Institute of Technology, Andrew and Peggy Cherng Department of Medical Engineering, Pasadena, California, United States
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35
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Schroeder B, Zhu ZH, Guo C, Jia S. Engineering and Optimization of Quasi-Nondiffracting Helicon-Like Beams With an Evolutionary Algorithm. IEEE Photonics J 2017; 9:6101109. [PMID: 30135704 PMCID: PMC6101657 DOI: 10.1109/jphot.2017.2708816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Nondiffracting beams maintain their intensity profiles over a large propagation distance without substantial diffraction and exhibit unique propagation trajectories, leading to scientific impacts in various fields. However, the nonlocalized intensity distribution of non-diffracting beams is restrictive for many practical applications. Thus, strategies to optimize the beam profiles remain much in demand. In this report, we demonstrate an evolutionary algorithmic framework for optical beam engineering and optimization and experimentally validate it by realizing quasi-nondiffracting radially self-accelerating (or self-rotating) beams in a high-resolution imaging system. The work reports a tightly confined side-lobe-suppressed helicon-like beam that largely maintains its properties of radial self-acceleration and non-diffraction in the 3-D space. The optimization method represents a new methodological avenue that can be extended to a broad range of beam engineering problems.
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Affiliation(s)
- Bryce Schroeder
- Department of Biomedical Engineering, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
- Medical Scientist Training Program, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
| | - Zhen H Zhu
- Department of Biomedical Engineering, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
| | - Changliang Guo
- Department of Biomedical Engineering, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
| | - Shu Jia
- Department of Biomedical Engineering, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
- Medical Scientist Training Program, Stony Brook University, State University of New York, Stony Brook, NY 11794 USA
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36
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Hemphill AS, Tay JW, Wang LV. Hybridized wavefront shaping for high-speed, high-efficiency focusing through dynamic diffusive media. J Biomed Opt 2016; 21:121502. [PMID: 27626770 PMCID: PMC5019185 DOI: 10.1117/1.jbo.21.12.121502] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/17/2016] [Indexed: 05/08/2023]
Abstract
One of the prime limiting factors of optical imaging in biological applications is the diffusion of light by tissue, which prevents focusing at depths greater than the optical diffusion limit (typically ?1??mm). To overcome this challenge, wavefront shaping techniques that use a spatial light modulator (SLM) to correct the phase of the incident wavefront have recently been developed. These techniques are able to focus light through scattering media beyond the optical diffusion limit. However, the low speeds of typically used liquid crystal SLMs limit the focusing speed. Here, we present a method using a digital micromirror device (DMD) and an electro-optic modulator (EOM) to measure the scattering-induced aberrations, and using a liquid crystal SLM to apply the correction to the illuminating wavefront. By combining phase modulation from an EOM with the DMD’s ability to provide selective illumination, we exploit the DMD’s higher refresh rate for phase measurement. We achieved focusing through scattering media in less than 8 ms, which is sufficiently short for certain in vivo applications, as it is comparable to the speckle correlation time of living tissue.
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Affiliation(s)
- Ashton S. Hemphill
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130, United States
| | - Jian Wei Tay
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, Saint Louis, Missouri 63130, United States
- Address all correspondence to: Lihong V. Wang, E-mail:
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37
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Shen Y, Liu Y, Ma C, Wang LV. Focusing light through biological tissue and tissue-mimicking phantoms up to 9.6 cm in thickness with digital optical phase conjugation. J Biomed Opt 2016; 21:85001. [PMID: 27533439 PMCID: PMC4982119 DOI: 10.1117/1.jbo.21.8.085001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/25/2016] [Indexed: 05/19/2023]
Abstract
Optical phase conjugation (OPC)-based wavefront shaping techniques focus light through or within scattering media, which is critically important for deep-tissue optical imaging, manipulation, and therapy. However, to date, the sample thickness in OPC experiments has been limited to only a few millimeters. Here, by using a laser with a long coherence length and an optimized digital OPC system that can safely deliver more light power, we focused 532-nm light through tissue-mimicking phantoms up to 9.6 cm thick, as well as through ex vivo chicken breast tissue up to 2.5 cm thick. Our results demonstrate that OPC can be achieved even when photons have experienced on average 1000 scattering events. The demonstrated penetration of nearly 10 cm (∼100 transport mean free paths) has never been achieved before by any optical focusing technique, and it shows the promise of OPC for deep-tissue noninvasive optical imaging, manipulation, and therapy.
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Affiliation(s)
- Yuecheng Shen
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Yan Liu
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Cheng Ma
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
| | - Lihong V. Wang
- Washington University in St. Louis, Optical Imaging Laboratory, Department of Biomedical Engineering, One Brookings Drive, St. Louis, Missouri 63130, United States
- Address all correspondence to: Lihong V. Wang, E-mail:
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Park J, Cho JY, Park C, Lee K, Lee H, Cho YH, Park Y. Scattering Optical Elements: Stand-Alone Optical Elements Exploiting Multiple Light Scattering. ACS Nano 2016; 10:6871-6876. [PMID: 27331616 DOI: 10.1021/acsnano.6b02592] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Optical design and fabrication techniques are crucial for making optical elements. From conventional lenses to diffractive optical elements and to recent metasurfaces, various types of optical elements have been proposed to manipulate light where optical materials are fabricated into desired structures. Here, we propose a scattering optical element (SOE) that exploits multiple light scattering and wavefront shaping. Instead of fabricating optical materials, the SOE consists of a disordered medium and a photopolymer-based wavefront recorder, with shapes impinging on light on demand. With the proposed stand-alone SOEs, we experimentally demonstrate control of various properties of light, including intensity, polarization, spectral frequency, and near field. Due to the tremendous freedom brought about by disordered media, the proposed approach will provide unexplored routes to manipulate arbitrary optical fields in stand-alone optical elements.
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Affiliation(s)
| | - Joong-Yeon Cho
- Department of Materials Science and Engineering, Korea University , Seoul 136-713, Republic of Korea
| | | | | | - Heon Lee
- Department of Materials Science and Engineering, Korea University , Seoul 136-713, Republic of Korea
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Abstract
UNLABELLED There have been two recent revolutionary advances in neuroscience: First, genetically encoded activity sensors have brought the goal of optical detection of single action potentials in vivo within reach. Second, optogenetic actuators now allow the activity of neurons to be controlled with millisecond precision. These revolutions have now been combined, together with advanced microscopies, to allow "all-optical" readout and manipulation of activity in neural circuits with single-spike and single-neuron precision. This is a transformational advance that will open new frontiers in neuroscience research. Harnessing the power of light in the all-optical approach requires coexpression of genetically encoded activity sensors and optogenetic probes in the same neurons, as well as the ability to simultaneously target and record the light from the selected neurons. It has recently become possible to combine sensors and optical strategies that are sufficiently sensitive and cross talk free to enable single-action-potential sensitivity and precision for both readout and manipulation in the intact brain. The combination of simultaneous readout and manipulation from the same genetically defined cells will enable a wide range of new experiments as well as inspire new technologies for interacting with the brain. The advances described in this review herald a future where the traditional tools used for generations by physiologists to study and interact with the brain-stimulation and recording electrodes-can largely be replaced by light. We outline potential future developments in this field and discuss how the all-optical strategy can be applied to solve fundamental problems in neuroscience. SIGNIFICANCE STATEMENT This review describes the nexus of dramatic recent developments in optogenetic probes, genetically encoded activity sensors, and novel microscopies, which together allow the activity of neural circuits to be recorded and manipulated entirely using light. The optical and protein engineering strategies that form the basis of this "all-optical" approach are now sufficiently advanced to enable single-neuron and single-action potential precision for simultaneous readout and manipulation from the same functionally defined neurons in the intact brain. These advances promise to illuminate many fundamental challenges in neuroscience, including transforming our search for the neural code and the links between neural circuit activity and behavior.
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Defienne H, Barbieri M, Walmsley IA, Smith BJ, Gigan S. Two-photon quantum walk in a multimode fiber. Sci Adv 2016; 2:e1501054. [PMID: 27152325 PMCID: PMC4846436 DOI: 10.1126/sciadv.1501054] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 11/30/2015] [Indexed: 05/06/2023]
Abstract
Multiphoton propagation in connected structures-a quantum walk-offers the potential of simulating complex physical systems and provides a route to universal quantum computation. Increasing the complexity of quantum photonic networks where the walk occurs is essential for many applications. We implement a quantum walk of indistinguishable photon pairs in a multimode fiber supporting 380 modes. Using wavefront shaping, we control the propagation of the two-photon state through the fiber in which all modes are coupled. Excitation of arbitrary output modes of the system is realized by controlling classical and quantum interferences. This report demonstrates a highly multimode platform for multiphoton interference experiments and provides a powerful method to program a general high-dimensional multiport optical circuit. This work paves the way for the next generation of photonic devices for quantum simulation, computing, and communication.
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Affiliation(s)
- Hugo Defienne
- Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Universités, Collège de France, 24 rue Lhomond, F-75005 Paris, France
- Corresponding author. E-mail:
| | - Marco Barbieri
- Università degli Studi Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy
| | - Ian A. Walmsley
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU Oxford, UK
| | - Brian J. Smith
- Clarendon Laboratory, Department of Physics, University of Oxford, OX1 3PU Oxford, UK
| | - Sylvain Gigan
- Laboratoire Kastler Brossel, ENS-PSL Research University, CNRS, UPMC-Sorbonne Universités, Collège de France, 24 rue Lhomond, F-75005 Paris, France
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Mohammadi Estakhri N, Argyropoulos C, Alù A. Graded metascreens to enable a new degree of nanoscale light management. Philos Trans A Math Phys Eng Sci 2015; 373:rsta.2014.0351. [PMID: 26217059 PMCID: PMC4528829 DOI: 10.1098/rsta.2014.0351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/11/2015] [Indexed: 05/26/2023]
Abstract
Optical metasurfaces, typically referred to as two-dimensional metamaterials, are arrays of engineered subwavelength inclusions suitably designed to tailor the light properties, including amplitude, phase and polarization state, over deeply subwavelength scales. By exploiting anomalous localized interactions of surface elements with optical waves, metasurfaces can go beyond the functionalities offered by conventional diffractive optical gratings. The innate simplicity of implementation and the distinct underlying physics of their wave-matter interaction distinguish metasurfaces from three-dimensional metamaterials and provide a valuable means of moulding optical waves in the desired manner. Here, we introduce a general approach based on the electromagnetic equivalence principle to develop and synthesize graded, non-periodic metasurfaces to generate arbitrarily prescribed distributions of electromagnetic waves. Graded metasurfaces are realized with a single layer of spatially modulated, electrically polarizable nanoparticles, tailoring the scattering response of the surface with nanoscale resolutions. We discuss promising applications based on the proposed local wave management technique, including the design of ultrathin optical carpet cloaks, alignment-free polarization beam splitters and a novel approach to enable broadband light absorption enhancement in thin-film solar cells. This concept opens up a practical route towards efficient planarized optical structures with potential impact on the integrated nanophotonic technology.
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Affiliation(s)
- Nasim Mohammadi Estakhri
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA
| | - Christos Argyropoulos
- Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
| | - Andrea Alù
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, TX 78712, USA
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Abstract
The ability to control the propagation of light through scattering media is essential for atmospheric optics, astronomy, biomedical imaging and remote sensing. The optimization of focusing light through a scattering medium is of particular interest for the case of highly scattering materials. Optical wavefront beam-shaping plays a critical role in optimizing such a propagation; however, an enormous field of adjustable parameters makes the overall task complicated. Here, we propose and experimentally evaluate several variations on the standard continuous sequential algorithm that hold a promise of revealing new, faster and more efficient optimization algorithms for selecting an optical wavefront to focus light through a scattering medium. We demonstrate that the order in which pixels are chosen in the continuous sequential algorithm can lead to a 2-fold decrease in the number of iterations required to reach a given enhancement.
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Abstract
Multiphoton microscopy is the current method of choice for in vivo deep-tissue imaging. The long laser wavelength suffers less scattering, and the 3D-confined excitation permits the use of scattered signal light. However, the imaging depth is still limited because of the complex refractive index distribution of biological tissue, which scrambles the incident light and destroys the optical focus needed for high resolution imaging. Here, we demonstrate a wavefront-shaping scheme that allows clear imaging through extremely turbid biological tissue, such as the skull, over an extended corrected field of view (FOV). The complex wavefront correction is obtained and directly conjugated to the turbid layer in a noninvasive manner. Using this technique, we demonstrate in vivo submicron-resolution imaging of neural dendrites and microglia dynamics through the intact skulls of adult mice. This is the first observation, to our knowledge, of dynamic morphological changes of microglia through the intact skull, allowing truly noninvasive studies of microglial immune activities free from external perturbations.
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