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Yang S, Hu S. Perspectives on endoscopic functional photoacoustic microscopy. APPLIED PHYSICS LETTERS 2024; 125:030502. [PMID: 39022117 PMCID: PMC11251735 DOI: 10.1063/5.0201691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/27/2024] [Indexed: 07/20/2024]
Abstract
Endoscopy, enabling high-resolution imaging of deep tissues and internal organs, plays an important role in basic research and clinical practice. Recent advances in photoacoustic microscopy (PAM), demonstrating excellent capabilities in high-resolution functional imaging, have sparked significant interest in its integration into the field of endoscopy. However, there are challenges in achieving functional PAM in the endoscopic setting. This Perspective article discusses current progress in the development of endoscopic PAM and the challenges related to functional measurements. Then, it points out potential directions to advance endoscopic PAM for functional imaging by leveraging fiber optics, microfabrication, optical engineering, and computational approaches. Finally, it highlights emerging opportunities for functional endoscopic PAM in basic and translational biomedicine.
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Affiliation(s)
- Shuo Yang
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
| | - Song Hu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, USA
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2
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Yasui M, Iwataki R, Ishikawa M, Watanabe Y. Projection Mapping with a Brightly Lit Surrounding Using a Mixed Light Field Approach. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS 2024; 30:2217-2227. [PMID: 38446649 DOI: 10.1109/tvcg.2024.3372132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Projection mapping (PM) exhibits suboptimal performance in well-lit environments because of the interference caused by ambient light. This interference degrades the contrast of the projected images. Consequently, conventional methodologies restrict the application of PM to dimly lit settings, leading to an unnatural visual experience, as only the PM target is prominently illuminated. To overcome these limitations, we introduce an innovative approach that leverages a mixed light field, blending traditional PM with ray-controllable ambient lighting. This methodological combination, despite its simplicity, is effective because it ensures that the projector exclusively illuminates the PM target, preserving the optimal contrast. Precise control of ambient light rays is essential to prevent them from illuminating the PM target while adequately illuminating the surrounding environment. Furthermore, we propose the integration of a kaleidoscopic array with integral photography to generate dense light fields for ray-controllable ambient lighting. Additionally, we present an efficient binary-search-based calibration method tailored to this intricate optical system. Our optical simulations and the developed system collectively validate the effectiveness of our approach. Our results show that PM targets and ordinary objects coexist naturally in environments that are brightly lit as a result of our method, enhancing the overall visual experience.
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3
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Imiolczyk C, Pfau TK, Thiele S, Karst J, Floess M, Schmid M, Hentschel M, Giessen H. Ultracompact wavefront characterization of femtosecond 3D printed microlenses using double-frequency Ronchi interferometry. OPTICS EXPRESS 2024; 32:9777-9789. [PMID: 38571203 DOI: 10.1364/oe.516962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 02/08/2024] [Indexed: 04/05/2024]
Abstract
3D printed microoptics have become important tools for miniature endoscopy, novel CMOS-based on-chip sensors, OCT-fibers, among others. Until now, only image quality and spot diagrams were available for optical characterization. Here, we introduce Ronchi interferometry as ultracompact and quick quantitative analysis method for measuring the wavefront aberrations after propagating coherent light through the 3D printed miniature optics. We compare surface shapes by 3D confocal microscopy with optical characterizations by Ronchi interferograms. Phase retrieval gives us the transversal wave front aberration map, which indicates that the aberrations of our microlenses that have been printed with a Nanoscribe GT or Quantum X printer exhibit RMS wavefront aberrations as small as λ/20, Strehl ratios larger than 0.91, and near-diffraction limited modulation transfer functions. Our method will be crucial for future developments of 3D printed microoptics, as the method is ultracompact, ultra-stable, and very fast regarding measurement and evaluation. It could fit directly into a 3D printer and allows for in-situ measurements right after printing as well as fast iterations for improving the shape of the optical surface.
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Pan CF, Wang H, Wang H, S PN, Ruan Q, Wredh S, Ke Y, Chan JYE, Zhang W, Qiu CW, Yang JK. 3D-printed multilayer structures for high-numerical aperture achromatic metalenses. SCIENCE ADVANCES 2023; 9:eadj9262. [PMID: 38117894 PMCID: PMC10732525 DOI: 10.1126/sciadv.adj9262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/21/2023] [Indexed: 12/22/2023]
Abstract
Flat optics consisting of nanostructures of high-refractive index materials produce lenses with thin form factors that tend to operate only at specific wavelengths. Recent attempts to achieve achromatic lenses uncover a trade-off between the numerical aperture (NA) and bandwidth, which limits performance. Here, we propose a new approach to design high-NA, broadband, and polarization-insensitive multilayer achromatic metalenses (MAMs). We combine topology optimization and full-wave simulations to inversely design MAMs and fabricate the structures in low-refractive index materials by two-photon polymerization lithography. MAMs measuring 20 μm in diameter operating in the visible range of 400 to 800 nm with 0.5 and 0.7 NA were achieved with efficiencies of up to 42%. We demonstrate broadband imaging performance of the fabricated MAM under white light and RGB narrowband illuminations. These results highlight the potential of the 3D-printed multilayer structures for realizing broadband and multifunctional meta-devices with inverse design.
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Affiliation(s)
- Cheng-Feng Pan
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576, Singapore
| | - Hao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- College of Mechanical and Vehicle Engineering, Hunan University, Changsha 410082, China
- Greater Bay Area Institute for Innovation, Hunan University, Guangzhou 511300, China
| | - Hongtao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576, Singapore
| | - Parvathi Nair S
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science Technology and Research), Singapore 138634, Singapore
| | - Qifeng Ruan
- Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, China
| | - Simon Wredh
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Yujie Ke
- Institute of Materials Research and Engineering, A*STAR (Agency for Science Technology and Research), Singapore 138634, Singapore
| | - John You En Chan
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Wang Zhang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576, Singapore
| | - Joel K. W. Yang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
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Li Q, Shi H, Xi S, Jiang J, Zhang L, Liu Y. Stimulated-responsive refractive-diffractive biological hydrogel micro-optical element enabling achromatism via femtosecond laser lithography. OPTICS EXPRESS 2023; 31:29368-29379. [PMID: 37710738 DOI: 10.1364/oe.500484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 08/07/2023] [Indexed: 09/16/2023]
Abstract
Herein, we report a novel biological hydrogel-based achromatic refractive-diffractive micro-optical element with single-material apochromatism. Benefiting from the stimulated responsive property of the hydrogel, pH modulation yielded swelling and affected the refractive index of the element, enabling multi-wavelength focusing performance tuning and chromatic aberration adjustment. Using femtosecond laser lithography, we fabricated a separate hydrogel microlens and Fresnel zone plate and measured the tunable focusing performance while varying pH; the results were consistent with our simulation results. Furthermore, we designed and fabricated a hydrogel-based achromatic refractive-diffractive micro-optical element and demonstrated achromatism with respect to three wavelengths using only one material consisting of a microlens and a Fresnel zone plate. We characterized the optical focusing properties and observed smaller chromatic aberration. The potential applications of such hybrid microoptical elements include biomedical imaging and optical biology sensing.
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Flynn C, Cao H, Applegate BE, Tkaczyk TS. Fabrication of waveguide directional couplers using 2-photon lithography. OPTICS EXPRESS 2023; 31:26323-26334. [PMID: 37710495 PMCID: PMC10544952 DOI: 10.1364/oe.495363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 09/16/2023]
Abstract
Advances in 2-photon lithography have enabled in-lab production of sub-micron resolution and millimeter scale 3D optical components. The potential complex geometries are well suited to rapid prototyping and production of waveguide structures, interconnects, and waveguide directional couplers, furthering future development and miniaturization of waveguide-based imaging technologies. System alignment is inherent to the 2-photon process, obviating the need for manual assembly and allowing precise micron scale waveguide geometries not possible in traditional fused fiber coupler fabrication. Here we present the use of 2-photon lithography for direct printing of multi-mode waveguide couplers with air cladding and single mode waveguide couplers with uncured liquid photoresin cladding. Experimental results show reproducible coupling which can be modified by selected design parameters.
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Affiliation(s)
- Christopher Flynn
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77005, USA
| | - Haimu Cao
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Brian E. Applegate
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, 1450 San Pablo St., Los Angeles, CA 90033, USA
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Tomasz S. Tkaczyk
- Department of Bioengineering, Rice University, 6500 Main Street, Houston, TX 77005, USA
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
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Sanli UT, Rodgers G, Zdora MC, Qi P, Garrevoet J, Falch KV, Müller B, David C, Vila-Comamala J. Apochromatic X-ray focusing. LIGHT, SCIENCE & APPLICATIONS 2023; 12:107. [PMID: 37142565 PMCID: PMC10160054 DOI: 10.1038/s41377-023-01157-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 03/17/2023] [Accepted: 04/11/2023] [Indexed: 05/06/2023]
Abstract
Achromatic doublets are combinations of two individual lenses designed to focus different wavelengths of light in the same position. Apochromatic optics are improved versions of the achromatic schemes which extend the wavelength range significantly. Both achromatic and apochromatic optics are well-established for visible light. However, X-ray achromatic lenses did not exist until very recently, and X-ray apochromatic lenses have never been experimentally demonstrated. Here, we create an X-ray apochromatic lens system using an appropriate combination of a Fresnel zone plate and a diverging compound refractive lens with a tuned separation distance. The energy-dependent performance of this apochromat was characterized at photon energies between 6.5 and 13.0 keV by ptychographic reconstruction of the focal spot and scanning transmission X-ray microscopy of a resolution test sample. The apochromat delivered a reconstructed focal spot size of 940 × 740 nm2. The apochromatic combination shows a four-fold improvement in the chromatic aberration correction range compared to an achromatic doublet configuration. Thus, apochromatic X-ray optics have the potential to increase the focal spot intensity for a wide variety of X-ray applications.
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Affiliation(s)
- Umut T Sanli
- Paul Scherrer Institute, Laboratory for X-ray Nanoscience and Technologies, Forschungsstrasse 111, 5232, Villigen, Switzerland.
| | - Griffin Rodgers
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Hegenheimermattweg 167 B, 4123, Allschwil, Switzerland
| | - Marie-Christine Zdora
- Paul Scherrer Institute, Laboratory for X-ray Nanoscience and Technologies, Forschungsstrasse 111, 5232, Villigen, Switzerland
| | - Peng Qi
- Paul Scherrer Institute, Laboratory for X-ray Nanoscience and Technologies, Forschungsstrasse 111, 5232, Villigen, Switzerland
| | - Jan Garrevoet
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Ken Vidar Falch
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Bert Müller
- Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Hegenheimermattweg 167 B, 4123, Allschwil, Switzerland
| | - Christian David
- Paul Scherrer Institute, Laboratory for X-ray Nanoscience and Technologies, Forschungsstrasse 111, 5232, Villigen, Switzerland
| | - Joan Vila-Comamala
- Paul Scherrer Institute, Laboratory for X-ray Nanoscience and Technologies, Forschungsstrasse 111, 5232, Villigen, Switzerland
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Siegle L, Ristok S, Giessen H. Complex aspherical singlet and doublet microoptics by grayscale 3D printing. OPTICS EXPRESS 2023; 31:4179-4189. [PMID: 36785392 DOI: 10.1364/oe.480472] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 12/31/2022] [Indexed: 06/18/2023]
Abstract
We demonstrate 3D printed aspherical singlet and doublet microoptical components by grayscale lithography and characterize and evaluate their excellent shape accuracy and optical performance. The typical two-photon polymerization (2PP) 3D printing process creates steps in the structure which is undesired for optical surfaces. We utilize two-photon grayscale lithography (2GL) to create step-free lenses. To showcase the 2GL process, the focusing ability of a spherical and aspherical singlet lens are compared. The surface deviations of the aspherical lens are minimized by an iterative design process and no distinct steps can be measured via confocal microscopy. We design, print, and optimize an air-spaced doublet lens with a diameter of 300 µm. After optimization, the residual shape deviation is less than 100 nm for the top lens and 20 nm for the bottom lens of the doublet. We examine the optical performance with an USAF 1951 resolution test chart to find a resolution of 645 lp/mm.
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Schmid M, Thiele S, Herkommer A, Giessen H. Adjustment-free two-sided 3D direct laser writing for aligned micro-optics on both substrate sides. OPTICS LETTERS 2023; 48:131-134. [PMID: 36563386 DOI: 10.1364/ol.476448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/11/2022] [Indexed: 06/17/2023]
Abstract
3D direct laser writing is a powerful and widely used tool to create complex micro-optics. The fabrication method offers two different writing modes. During the immersion mode, an immersion medium is applied between the objective and the substrate while the photoresist is exposed on its back side. Alternatively, when using the dip-in mode, the objective is in direct contact with the photoresist and the structure is fabricated on the objective facing side of the substrate. In this Letter, we demonstrate the combination of dip-in and photoresist immersion printing, by using the photoresist itself as immersion medium. This way, two parts of a doublet objective can be fabricated on the front and back sides of a substrate, using it as a spacer with a lateral registration below 1 µm and without the need of additional alignment. This approach also enables the alignment free combination of different photoresists on the back and front sides. We use this benefit by printing a black aperture on the back of the substrate, while the objective lens is printed on the front.
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Schmid M, Giessen H. Stress-induced birefringence in 3D direct laser written micro-optics. OPTICS LETTERS 2022; 47:5789-5792. [PMID: 37219104 DOI: 10.1364/ol.476464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 10/17/2022] [Indexed: 05/24/2023]
Abstract
3D direct laser writing is a widely used technology to create different nano- and micro-optical devices for various purposes. However, one big issue is the shrinking of the structures during polymerization, which results in deviations from the design and in internal stress. While the deviations can be compensated by adapting the design, the internal stress remains and induces birefringence. In this Letter, we successfully demonstrate the quantitative analysis of stress-induced birefringence in 3D direct laser written structures. After presenting the measurement setup based on a rotating polarizer and an elliptical analyzer, we characterize the birefringence of different structures and writing modes. We further investigate different photoresists and the implications for 3D direct laser written optics.
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Tan M, Huang L, Cao J, Zhang H, Zhao S, Liu M, Jia Z, Zhai R, Liu H. Microflow multi-layer diffraction optical element processed by hybrid manufacturing technology. OPTICS EXPRESS 2022; 30:24689-24702. [PMID: 36237017 DOI: 10.1364/oe.464192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/13/2022] [Indexed: 06/16/2023]
Abstract
Traditional planar diffractive optical elements (DOEs) are challenged in imaging systems due to diffraction efficiency and chromatic dispersion. In this paper, we have designed a microfluidic diffractive optical element (MFDOE), which is processed by digital micromirror device (DMD) maskless lithography (DMDML) assisted femtosecond laser direct writing (FsLDW). MFDOE is a combination of photoresist-based multi-layer harmonic diffraction surface and liquid, realizing diffraction efficiency of more than 90% in the visible band. And it shows achromatic characteristics in the two bands of 469 nm (±20 nm) and 625 nm (±20 nm). These results show that MFDOE has good imaging performance.
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Toulouse A, Drozella J, Motzfeld P, Fahrbach N, Aslani V, Thiele S, Giessen H, Herkommer AM. Ultra-compact 3D-printed wide-angle cameras realized by multi-aperture freeform optical design. OPTICS EXPRESS 2022; 30:707-720. [PMID: 35209256 DOI: 10.1364/oe.439963] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/07/2021] [Indexed: 06/14/2023]
Abstract
Simultaneous realization of ultra-large field of view (FOV), large lateral image size, and a small form factor is one of the challenges in imaging lens design and fabrication. All combined this yields an extensive flow of information while conserving ease of integration where space is limited. Here, we present concepts, correction methods and realizations towards freeform multi-aperture wide-angle cameras fabricated by femtosecond direct laser writing (fsDLW). The 3D printing process gives us the design freedom to create 180° × 360° cameras with a flat form factor in the micrometer range by splitting the FOV into several apertures. Highly tilted and decentered non-rotational lens shapes as well as catadioptric elements are used in the optical design to map the FOV onto a flat surface in a Scheimpflug manner. We present methods to measure and correct freeform surfaces with up to 180° surface normals by confocal measurements, and iterative fabrication via fsDLW. Finally, approaches for digital distortion correction and image stitching are demonstrated and two realizations of freeform multi-aperture wide-angle cameras are presented.
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Abstract
A pilot study on laser 3D printing of inorganic free-form micro-optics is experimentally validated. Ultrafast laser direct-write (LDW) nanolithography is employed for structuring hybrid organic-inorganic material SZ2080TM followed by high-temperature calcination post-processing. The combination allows the production of 3D architectures and the heat-treatment results in converting the material to inorganic substances. The produced miniature optical elements are characterized and their optical performance is demonstrated. Finally, the concept is validated for manufacturing compound optical components such as stacked lenses. This is an opening for new directions and applications of laser-made micro-optics under harsh conditions such as high intensity radiation, temperature, acidic environment, pressure variations, which include open space, astrophotonics, and remote sensing.
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