1
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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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Zhang R, Qiao S, Luo Y, Guo Y, Li X, Zhang Q, Fan Y, Zhao Z, Luo X. Structured-Light 3D Imaging Based on Vector Iterative Fourier Transform Algorithm. NANOMATERIALS (BASEL, SWITZERLAND) 2024; 14:929. [PMID: 38869554 PMCID: PMC11174106 DOI: 10.3390/nano14110929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 05/16/2024] [Accepted: 05/22/2024] [Indexed: 06/14/2024]
Abstract
Quasi-continuous-phase metasurfaces overcome the side effects imposed by high-order diffraction on imaging and can impart optical parameters such as amplitude, phase, polarization, and frequency to incident light at sub-wavelength scales with high efficiency. Structured-light three-dimensional (3D) imaging is a hot topic in the field of 3D imaging because of its advantages of low computation cost, high imaging accuracy, fast imaging speed, and cost-effectiveness. Structured-light 3D imaging requires uniform diffractive optical elements (DOEs), which could be realized by quasi-continuous-phase metasurfaces. In this paper, we design a quasi-continuous-phase metasurface beam splitter through a vector iterative Fourier transform algorithm and utilize this device to realize structured-light 3D imaging of a target object with subsequent target reconstruction. A structured-light 3D imaging system is then experimentally implemented by combining the fabricated quasi-continuous-phase metasurface illuminated by the vertical-cavity surface-emitting laser and a binocular recognition system, which eventually provides a new technological path for the 3D imaging field.
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Affiliation(s)
- Runzhe Zhang
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
- Tianfu Xinglong Lake Laboratory, Chengdu 610299, China
| | - Siyuan Qiao
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
- Tianfu Xinglong Lake Laboratory, Chengdu 610299, China
| | - Yixiong Luo
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yinghui Guo
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyin Li
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
| | - Qi Zhang
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
| | - Yulong Fan
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
| | - Zeyu Zhao
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiangang Luo
- National Key Laboratory of Optical Field Manipulation Science and Technology, Chinese Academy of Sciences, Chengdu 610209, China; (R.Z.); (S.Q.); (Y.L.); (Y.G.); (X.L.); (Q.Z.); (Y.F.)
- State Key Laboratory of Optical Technologies on Nano-Fabrication and Micro-Engineering, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- Research Center on Vector Optical Fields, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu 610209, China
- School of Optoelectronics, University of Chinese Academy of Sciences, Beijing 100049, China
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Porfirev A, Khonina S, Porfirev D, Ivliev N. Structured polarized laser beams for controlled spiral-shaped mass transfer in azopolymer thin films. APPLIED OPTICS 2024; 63:3779-3784. [PMID: 38856340 DOI: 10.1364/ao.521196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/16/2024] [Indexed: 06/11/2024]
Abstract
We present an approach for the realization of controlled spiral-shaped mass transfer in azopolymer thin films and the fabrication of spiral microreliefs. For such laser processing, we propose to use light fields with structured polarization distributions generated by a transmissive spatial light modulator. The projection lithography approach is utilized, transferring the pattern directly to the surface of azopolymer thin films. The shaped polarization distributions with different dependencies of the polarization vector orientation on the azimuthal angle allow us to drive surface waves on the sample along a spiral trajectory. Additionally, the ability to control the concavity of the formed microreliefs is demonstrated. This approach can be effectively modified for the direct laser fabrication of more complex nano-/micro-elements as well as their arrays.
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Hu J, Mengu D, Tzarouchis DC, Edwards B, Engheta N, Ozcan A. Diffractive optical computing in free space. Nat Commun 2024; 15:1525. [PMID: 38378715 PMCID: PMC10879514 DOI: 10.1038/s41467-024-45982-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 02/09/2024] [Indexed: 02/22/2024] Open
Abstract
Structured optical materials create new computing paradigms using photons, with transformative impact on various fields, including machine learning, computer vision, imaging, telecommunications, and sensing. This Perspective sheds light on the potential of free-space optical systems based on engineered surfaces for advancing optical computing. Manipulating light in unprecedented ways, emerging structured surfaces enable all-optical implementation of various mathematical functions and machine learning tasks. Diffractive networks, in particular, bring deep-learning principles into the design and operation of free-space optical systems to create new functionalities. Metasurfaces consisting of deeply subwavelength units are achieving exotic optical responses that provide independent control over different properties of light and can bring major advances in computational throughput and data-transfer bandwidth of free-space optical processors. Unlike integrated photonics-based optoelectronic systems that demand preprocessed inputs, free-space optical processors have direct access to all the optical degrees of freedom that carry information about an input scene/object without needing digital recovery or preprocessing of information. To realize the full potential of free-space optical computing architectures, diffractive surfaces and metasurfaces need to advance symbiotically and co-evolve in their designs, 3D fabrication/integration, cascadability, and computing accuracy to serve the needs of next-generation machine vision, computational imaging, mathematical computing, and telecommunication technologies.
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Affiliation(s)
- Jingtian Hu
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Bioengineering Department, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute (CNSI), University of California, Los Angeles, CA, 90095, USA
| | - Deniz Mengu
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA
- Bioengineering Department, University of California, Los Angeles, CA, 90095, USA
- California NanoSystems Institute (CNSI), University of California, Los Angeles, CA, 90095, USA
| | - Dimitrios C Tzarouchis
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
- Meta Materials Inc., Athens, 15123, Greece
| | - Brian Edwards
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nader Engheta
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Aydogan Ozcan
- Electrical and Computer Engineering Department, University of California, Los Angeles, CA, 90095, USA.
- Bioengineering Department, University of California, Los Angeles, CA, 90095, USA.
- California NanoSystems Institute (CNSI), University of California, Los Angeles, CA, 90095, USA.
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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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6
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Baek S, Jeong S, Ban HW, Ryu J, Kim Y, Gu DH, Son C, Yoon TS, Lee J, Son JS. Nanoscale Vertical Resolution in Optical Printing of Inorganic Nanoparticles. ACS NANO 2023. [PMID: 38044586 DOI: 10.1021/acsnano.3c09787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Direct optical printing of functional inorganics shows tremendous potential as it enables the creation of intricate two-dimensional (2D) patterns and affordable design and production of various devices. Although there have been recent advancements in printing processes using short-wavelength light or pulsed lasers, the precise control of the vertical thickness in printed 3D structures has received little attention. This control is vital to the diverse functionalities of inorganic thin films and their devices, as they rely heavily on their thicknesses. This lack of research is attributed to the technical intricacy and complexity involved in the lithographic processes. Herein, we present a generalized optical 3D printing process for inorganic nanoparticles using maskless digital light processing. We develop a range of photocurable inorganic nanoparticle inks encompassing metals, semiconductors, and oxides, combined with photolinkable ligands and photoacid generators, enabling the direct solidification of nanoparticles in the ink medium. Our process creates complex and large-area patterns with a vertical resolution of ∼50 nm, producing 50-nm-thick 2D films and several micrometer-thick 3D architectures with no layer height difference via layer-by-layer deposition. Through fabrication and operation of multilayered switching devices with Au electrodes and Ag-organic resistive layers, the feasibility of our process for cost-effective manufacturing of multilayered devices is demonstrated.
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Affiliation(s)
- Seongheon Baek
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Sanggyun Jeong
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Hyeong Woo Ban
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jiyeon Ryu
- Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Yoonkyum Kim
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Da Hwi Gu
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Changil Son
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Tae-Sik Yoon
- Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jiseok Lee
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jae Sung Son
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Gyeongsangbuk-do, 37673, Republic of Korea
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Zhu D, Zhang J, Xu Q, Li Y. Two-photon polymerization of silica glass diffractive micro-optics with minimal lateral shrinkage. OPTICS EXPRESS 2023; 31:36037-36047. [PMID: 38017762 DOI: 10.1364/oe.499528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/19/2023] [Indexed: 11/30/2023]
Abstract
Three-dimensional printing enables the fabrication of silica glass optics with complex structures. However, shrinkage remains a significant obstacle to high-precision 3D printing of glass optics. Here we 3D-printed Dammann gratings (DGs) with low lateral shrinkage (<4%) using a two-photon polymerization (2PP) technique. The process consists of two steps: patterning two-photon polymerizable glass slurry with a 515 nm femtosecond laser to form desired structures and debinding/sintering the structures into transparent and dense silica glass. The sintered structures exhibited distinct shrinkage rates in the lateral against longitudinal directions. As the aspect ratio of the structures increased, the lateral shrinkage decreased, while the longitudinal shrinkage increased. Specifically, the structure with an aspect ratio of approximately 60 achieved a minimal lateral shrinkage of 1.1%, the corresponding longitudinal shrinkage was 61.7%. The printed DGs with a surface roughness below 20 nm demonstrated good beam-shaping performance. The presented technique opens up possibilities for rapid prototyping of silica diffractive optical elements.
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Zhu H, Li M, Hu T, Zhao M, Yang Z. Three-dimensional printing of a beam expander to enable the combination of hundred-micron optical elements and a single-mode fiber. OPTICS LETTERS 2023; 48:5379-5382. [PMID: 37831872 DOI: 10.1364/ol.499114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/14/2023] [Indexed: 10/15/2023]
Abstract
We use a flexible two-photon photopolymerization direct laser writing to fabricate an integrated diffractive lens system on a fiber tip to expand the output beam of the fiber. The results show that the micro-integrated beam expander based on double lenses (axial size of about 100 μm) has a magnification of 5.9 and a loss of 0.062 dB. Subsequently, we demonstrate the fabrication of a spiral phase plate (diffractive optical elements) and micro-lens arrays (refractive optical elements) on an integrated beam expander, and their optical properties are measured and analyzed, respectively. This Letter is an exploration of the future integrated micro-optical systems on an optical fiber tip.
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Mori T, Wang H, Zhang W, Ser CC, Arora D, Pan CF, Li H, Niu J, Rahman MA, Mori T, Koishi H, Yang JKW. Pick and place process for uniform shrinking of 3D printed micro- and nano-architected materials. Nat Commun 2023; 14:5876. [PMID: 37735573 PMCID: PMC10514194 DOI: 10.1038/s41467-023-41535-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 09/08/2023] [Indexed: 09/23/2023] Open
Abstract
Two-photon polymerization lithography is promising for producing three-dimensional structures with user-defined micro- and nanoscale features. Additionally, shrinkage by thermolysis can readily shorten the lattice constant of three-dimensional photonic crystals and enhance their resolution and mechanical properties; however, this technique suffers from non-uniform shrinkage owing to substrate pinning during heating. Here, we develop a simple method using poly(vinyl alcohol)-assisted uniform shrinking of three-dimensional printed structures. Microscopic three-dimensional printed objects are picked and placed onto a receiving substrate, followed by heating to induce shrinkage. We show the successful uniform heat-shrinking of three-dimensional prints with various shapes and sizes, without sacrificial support structures, and observe that the surface properties of the receiving substrate are important factors for uniform shrinking. Moreover, we print a three-dimensional mascot model that is then uniformly shrunk, producing vivid colors from colorless woodpile photonic crystals. The proposed method has significant potential for application in mechanics, optics, and photonics.
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Affiliation(s)
- Tomohiro Mori
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore.
- Industrial Technology Center of Wakayama Prefecture, Wakayama, 6496261, Japan.
| | - 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.
| | - Wang Zhang
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Chern Chia Ser
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Deepshikha Arora
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - 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, Singapore, 117576, Singapore
| | - Hao Li
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Jiabin Niu
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - M A Rahman
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore
| | - Takeshi Mori
- Industrial Technology Center of Wakayama Prefecture, Wakayama, 6496261, Japan
| | - Hideyuki Koishi
- Industrial Technology Center of Wakayama Prefecture, Wakayama, 6496261, Japan
| | - Joel K W Yang
- Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore.
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Zhang Z, He B, Han Q, He R, Ding Y, Han B, Ma ZC. Femtosecond Laser Direct Writing of Gecko-Inspired Switchable Adhesion Interfaces on a Flexible Substrate. MICROMACHINES 2023; 14:1742. [PMID: 37763905 PMCID: PMC10534918 DOI: 10.3390/mi14091742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
Biomimetic switchable adhesion interfaces (BSAIs) with dynamic adhesion states have demonstrated significant advantages in micro-manipulation and bio-detection. Among them, gecko-inspired adhesives have garnered considerable attention due to their exceptional adaptability to extreme environments. However, their high adhesion strength poses challenges in achieving flexible control. Herein, we propose an elegant and efficient approach by fabricating three-dimensional mushroom-shaped polydimethylsiloxane (PDMS) micropillars on a flexible PDMS substrate to mimic the bending and stretching of gecko footpads. The fabrication process that employs two-photon polymerization ensures high spatial resolution, resulting in micropillars with exquisite structures and ultra-smooth surfaces, even for tip/stem ratios exceeding 2 (a critical factor for maintaining adhesion strength). Furthermore, these adhesive structures display outstanding resilience, enduring 175% deformation and severe bending without collapse, ascribing to the excellent compatibility of the micropillar's composition and physical properties with the substrate. Our BSAIs can achieve highly controllable adhesion force and rapid manipulation of liquid droplets through mechanical bending and stretching of the PDMS substrate. By adjusting the spacing between the micropillars, precise control of adhesion strength is achieved. These intriguing properties make them promising candidates for various applications in the fields of microfluidics, micro-assembly, flexible electronics, and beyond.
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Affiliation(s)
- Zhiang Zhang
- Department of Automation, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bingze He
- Institute of Medical Robotics, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qingqing Han
- Department of Automation, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ruokun He
- Department of Automation, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yuxuan Ding
- Institute of Medical Robotics, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bing Han
- Institute of Medical Robotics, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhuo-Chen Ma
- Department of Automation, Shanghai Jiao Tong University, Shanghai 200240, China
- Institute of Medical Robotics, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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11
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Wagner S, Treptow K, Weser S, Drexler M, Sahakalkan S, Eberhardt W, Guenther T, Pruss C, Herkommer A, Zimmermann A. Injection Molding of Encapsulated Diffractive Optical Elements. MICROMACHINES 2023; 14:1223. [PMID: 37374806 DOI: 10.3390/mi14061223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/02/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023]
Abstract
Microstructuring techniques, such as laser direct writing, enable the integration of microstructures into conventional polymer lens systems and may be used to generate advanced functionality. Hybrid polymer lenses combining multiple functions such as diffraction and refraction in a single component become possible. In this paper, a process chain to enable encapsulated and aligned optical systems with advanced functionality in a cost-efficient way is presented. Within a surface diameter of 30 mm, diffractive optical microstructures are integrated in an optical system based on two conventional polymer lenses. To ensure precise alignment between the lens surfaces and the microstructure, resist-coated ultra-precision-turned brass substrates are structured via laser direct writing, and the resulting master structures with a height of less than 0.002 mm are replicated into metallic nickel plates via electroforming. The functionality of the lens system is demonstrated through the production of a zero refractive element. This approach provides a cost-efficient and highly accurate method for producing complicated optical systems with integrated alignment and advanced functionality.
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Affiliation(s)
- Stefan Wagner
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany
- Institute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany
| | - Kevin Treptow
- Institute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany
| | - Sascha Weser
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany
| | - Marc Drexler
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany
| | | | | | - Thomas Guenther
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany
- Institute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany
| | - Christof Pruss
- Institute for Applied Optics, Pfaffenwaldring 9, 70569 Stuttgart, Germany
| | - Alois Herkommer
- Institute for Applied Optics, Pfaffenwaldring 9, 70569 Stuttgart, Germany
| | - André Zimmermann
- Hahn-Schickard, Allmandring 9B, 70569 Stuttgart, Germany
- Institute for Micro Integration (IFM), Faculty 7-Engineering Design, Production Engineering and Automotive Engineering, University of Stuttgart, Allmandring 9B, 70569 Stuttgart, Germany
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12
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Miao D, Zhao YY, Cai SC, Li ZX, Chen JT, An JN, Duan XM. Generating an M 2 × N 2 spot array with a dual-period hybrid Dammann grating fabricated using maskless projection lithography. OPTICS LETTERS 2023; 48:3087-3090. [PMID: 37262287 DOI: 10.1364/ol.488122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 05/02/2023] [Indexed: 06/03/2023]
Abstract
The Dammann grating (DG), which redistributes a collimated laser beam into a spot array with a uniform intensity, is a widely adopted approach for profile measurement. Conventional DGs for dense spot projection are binary phase gratings with precisely designed groove structures, which suffer from low efficiency, poor uniformity, and a hard-to-fabricate fine feature size when utilized for a large field of view (FOV). Here, we propose a new, to the best of our knowledge, hybrid DG architecture consisting of two different grating periods which effectively generates an engineering M2 × N2 spot array with a non-complex structural design. As a proof-of-concept, a dual-period hybrid DG with a two-scale grating period ratio of 11.88 μm/95.04 μm (∼1/8) is designed and fabricated as a means to generate a dense 72 × 72 diffraction spot array with a FOV of 17° × 17°. In addition, the DG exhibits superior performance, with a high efficiency (>60%) and a low non-uniformity (<18%) at a wavelength of 532 nm. This kind of hybrid DG constructed from photoresist patterns with a minimum feature size of ∼1.2 μm can be perfectly fabricated by maskless projection lithography for large-scale and low-cost production. The proposed dual-period hybrid DG can pave the way for depth-perception-related applications such as face unlocking and motion sensing.
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13
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Jia W, Lin D, Menon R, Sensale-Rodriguez B. Machine learning enables the design of a bidirectional focusing diffractive lens. OPTICS LETTERS 2023; 48:2425-2428. [PMID: 37126289 DOI: 10.1364/ol.489535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Machine learning can efficiently empower the inverse design of cascaded diffractive optical elements. In this work, we explore the inverse design of a bidirectional focusing diffractive lens in a cascaded configuration through the diffractive optical neural network (DONN) machine learning method. The bidirectional focusing diffractive lens consists of two on-axially cascaded multi-level diffractive lenses. Each lens consists of concentric rings with equal widths and varying heights. The height of each concentric ring is optimized as part of the design algorithm. The diffractive lens has a focal length f+ as light propagates in the forward (Z+) direction. As light propagates in the backward (Z-) direction, the focal length changes to f-. The designed lens is fabricated through a two-photon polymerization 3D printing technique. The proposed design is polarization insensitive and miniature and can be readily applied in future functional optical imaging systems.
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14
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Yu Y, Prudnikau A, Lesnyak V, Kirchner R. Quantum Dots Facilitate 3D Two-Photon Laser Lithography. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2211702. [PMID: 37042293 DOI: 10.1002/adma.202211702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 04/07/2023] [Indexed: 06/04/2023]
Abstract
In the past two decades, direct laser writing (DLW) technologies have seen tremendous growth. However, strategies that enhance the printing resolution and the development of printing material with assorted functionalities are still sparser than expected. Herein, a cost-effective method to tackle this bottleneck is presented. Semiconductor quantum dots (QDs) are selected to carry out this task, most importantly via surface chemistry modification to enable their copolymerization with themonomers, resulting in transparent composites. The evaluations indicate that the QDs show great colloidal stability and their photoluminescent properties are well-preserved. This allows further exploration of the printing characteristics of such composite material. It is shown that in the presence of the QDs, the material provides a much lower polymerization threshold with faster linewidth growth, indicating that the QDs form a synergetic relationship with the monomer and the photoinitiator, widening the dynamic range of the material and thus increasing the writing efficiency for broader fields of applications. Lowering the polymerization threshold reduces the minimum achievable feature size by ≈32%, which is well-matched with STED-based (i.e., stimulated-emission depletion microscopy) methods in writing 3D structures. The study further elucidates the mechanism of the synergetic behavior, further guiding the future development of functional materials for DLW-related printing technologies.
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Affiliation(s)
- Ye Yu
- Institute of Semiconductors and Microsystems, Technische Universität Dresden, Nöthnitzer Straße 64, 01187, Dresden, Germany
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062, Dresden, Germany
| | - Anatol Prudnikau
- Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069, Dresden, Germany
| | - Vladimir Lesnyak
- Physical Chemistry, Technische Universität Dresden, Zellescher Weg 19, 01069, Dresden, Germany
| | - Robert Kirchner
- Institute of Semiconductors and Microsystems, Technische Universität Dresden, Nöthnitzer Straße 64, 01187, Dresden, Germany
- Center for Advancing Electronics Dresden (cfaed), Technische Universität Dresden, 01062, Dresden, Germany
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15
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Xiong Y, Shepherd S, Tibbs J, Bacon A, Liu W, Akin LD, Ayupova T, Bhaskar S, Cunningham BT. Photonic Crystal Enhanced Fluorescence: A Review on Design Strategies and Applications. MICROMACHINES 2023; 14:668. [PMID: 36985075 PMCID: PMC10059769 DOI: 10.3390/mi14030668] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/03/2023] [Accepted: 03/13/2023] [Indexed: 05/25/2023]
Abstract
Nanoscale fluorescence emitters are efficient for measuring biomolecular interactions, but their utility for applications requiring single-unit observations is constrained by the need for large numerical aperture objectives, fluorescence intermittency, and poor photon collection efficiency resulting from omnidirectional emission. Photonic crystal (PC) structures hold promise to address the aforementioned challenges in fluorescence enhancement. In this review, we provide a broad overview of PCs by explaining their structures, design strategies, fabrication techniques, and sensing principles. Furthermore, we discuss recent applications of PC-enhanced fluorescence-based biosensors incorporated with emerging technologies, including nucleic acids sensing, protein detection, and steroid monitoring. Finally, we discuss current challenges associated with PC-enhanced fluorescence and provide an outlook for fluorescence enhancement with photonic-plasmonics coupling and their promise for point-of-care biosensing as well monitoring analytes of biological and environmental relevance. The review presents the transdisciplinary applications of PCs in the broad arena of fluorescence spectroscopy with broad applications in photo-plasmonics, life science research, materials chemistry, cancer diagnostics, and internet of things.
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Affiliation(s)
- Yanyu Xiong
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
| | - Skye Shepherd
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Joseph Tibbs
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Amanda Bacon
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Weinan Liu
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
| | - Lucas D. Akin
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Takhmina Ayupova
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Seemesh Bhaskar
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, Urbana, IL 61801, USA
| | - Brian T. Cunningham
- Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Nick Holonyak Jr. Micro and Nanotechnology Laboratory, Urbana, IL 61801, USA
- Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Carl R. Woese Institute for Genomic Biology, Urbana, IL 61801, USA
- Cancer Center at Illinois, Urbana, IL 61801, USA
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16
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Lei X, Peng S, Niu Y, Sun S, Zhu Y, Qiu J. Magnetically driven micro-optical choppers fabricated by two-photon polymerization. OPTICS LETTERS 2023; 48:835-838. [PMID: 36723601 DOI: 10.1364/ol.481982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/02/2023] [Indexed: 06/18/2023]
Abstract
In this Letter, a series of magnetically driven micro-optical choppers based on customized photoresist were fabricated by two-photon polymerization (TPP) technology. Synthetic Fe3O4 nanoparticles (NPs) were modified and dispersed in the original photoresist to achieve magnetic field response. After accurately formulating a magnetic photoresist containing Rhodamine B to reduce the light transmittance, four micro-optical choppers with different slot widths were printed using optimized processing parameters. The micro-optical choppers were remotely manipulated to rotate by the external magnetic field. More importantly, the function demonstration of the micro-optical choppers with an excellent chopping effect was achieved at a given light wavelength of 515 nm. The magnetically driven micro-optical choppers provide a new approach, to the best of our knowledge, for the fabrication of external field-responsive optical components.
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17
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Hemayat S, Hsu L, Ha J, Ndao A. Near-unity uniformity and efficiency broadband meta-beam-splitter/combiner. OPTICS EXPRESS 2023; 31:3984-3997. [PMID: 36785377 DOI: 10.1364/oe.480233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/24/2022] [Indexed: 06/18/2023]
Abstract
Subwavelength planar structured interfaces, also known as metasurfaces, are ultra-thin optical elements modulating the amplitude, phase, and polarization of incident light using nanostructures called meta-atoms. The optical properties of such metasurfaces can be controlled across wavelengths by selecting geometries and materials of the meta-atoms. Given recent technological developments in optical device miniaturization, components for beam splitting and beam combining are sought for use within these devices as two quintessential components of every optical setup. However, realizing such devices using metasurfaces typically leads to poor uniformity of diffraction orders and narrow-band operation. Using a modified version of particle swarm optimization, we propose and numerically demonstrate a broadband, reciprocal metasurface beam combiner/splitter with uniformity > 97% and diffraction efficiency > 90% in the continuous band from λ=1525 nm to λ=1575 nm. The proposed approach significantly extends the current state of the art of metasurfaces design in terms of uniformity, bandwidth, and efficiency, and opens the door for devices requiring high power or near-unit uniformity.
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18
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Benzylidene Cyclopentanone Derivative Photoinitiator for Two-Photon Photopolymerization-Photochemistry and 3D Structures Fabrication for X-ray Application. Polymers (Basel) 2022; 15:polym15010071. [PMID: 36616421 PMCID: PMC9823431 DOI: 10.3390/polym15010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/21/2022] [Accepted: 12/22/2022] [Indexed: 12/28/2022] Open
Abstract
Micron- and submicron-scale 3D structure realization nowadays is possible due to the two-photon photopolymerization (TPP) direct laser writing photolithography (DLW photolithography) method. However, the achievement of lithographic features with dimensions less than 100 nm is in demand for the fabrication of micro-optical elements with high curvature values, including X-ray microlenses. Spectroscopic and photochemical study of a photoinitiator (PI) based on a methyl methacrylate derivative of 2,5-bis(4-(dimethylamino)benzylidene) cyclopentanone was performed. Enhanced intersystem crossing in the methyl methacrylate derivative results in increased radical generation for the subsequent initiation of polymerization. A comprehensive study of the new photocompositions was performed, with particular emphasis on photochemical constants, the degree of photopolymerization, and topology. The optimal parameters for the fabrication of mechanically stable structures were determined in this research. The threshold dose parameters for lithography (radiation power of 5 mW at a speed of 180 µm/s) when trying to reach saturation values with a conversion degree of (35 ± 1) % were defined, as well as parameters for sub-100 nm feature fabrication. Moreover, the 45 nm feature size for elements was reached. Fabrication of X-ray lens microstructures was also demonstrated.
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19
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Zhang W, Wang H, Tan ATL, Sargur Ranganath A, Zhang B, Wang H, Chan JYE, Ruan Q, Liu H, Ha ST, Wang D, Ravikumar VK, Low HY, Yang JKW. Stiff Shape Memory Polymers for High-Resolution Reconfigurable Nanophotonics. NANO LETTERS 2022; 22:8917-8924. [PMID: 36354246 DOI: 10.1021/acs.nanolett.2c03007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Reconfigurable metamaterials require constituent nanostructures to demonstrate switching of shapes with external stimuli. Yet, a longstanding challenge is in overcoming stiction caused by van der Waals forces in the deformed configuration, which impedes shape recovery. Here, we introduce stiff shape memory polymers. This designer material has a storage modulus of ∼5.2 GPa at room temperature and ∼90 MPa in the rubbery state at 150 °C, 1 order of magnitude higher than those in previous reports. Nanopillars with diameters of ∼400 nm and an aspect ratio as high as ∼10 were printed by two-photon lithography. Experimentally, we observe shape recovery as collapsed and touching structures overcome stiction to stand back up. We develop a theoretical model to explain the recoverability of these sub-micrometer structures. Reconfigurable structural color prints with a resolution of 21150 dots per inch and holograms are demonstrated, indicating potential applications of the stiff shape memory polymers in high-resolution reconfigurable nanophotonics.
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Affiliation(s)
- Wang Zhang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Hao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Alvin T L Tan
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Anupama Sargur Ranganath
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Biao Zhang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Hongtao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - John You En Chan
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Qifeng Ruan
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Hailong Liu
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Son Tung Ha
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Dong Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Venkat K Ravikumar
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Hong Yee Low
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Joel K W Yang
- Engineering Product Development, Singapore University of Technology and Design, Singapore 487372, Singapore
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20
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Chan JYE, Ruan Q, Wang H, Wang H, Liu H, Yan Z, Qiu CW, Yang JKW. Full Geometric Control of Hidden Color Information in Diffraction Gratings under Angled White Light Illumination. NANO LETTERS 2022; 22:8189-8195. [PMID: 36227759 DOI: 10.1021/acs.nanolett.2c02741] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Under white light illumination, gratings produce an angular distribution of wavelengths dependent on the diffraction order and geometric parameters. However, previous studies of gratings are limited to at least one geometric parameter (height, periodicity, orientation, angle of incidence) kept constant. Here, we vary all geometric parameters in the gratings using a versatile nanofabrication technique, two-photon polymerization lithography, to encode hidden color information through two design approaches. The first approach hides color information by decoupling the effects of grating height and periodicity under normal and oblique incidence. The second approach hides multiple sets of color information by arranging gratings in sectors around semicircular pixels. Different images are revealed with negligible crosstalk under oblique incidence and varying sample rotation angles. Our analysis shows that an angular separation of ≥10° between adjacent sectors is required to suppress crosstalk. This work has potential applications in information storage and security watermarks.
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Affiliation(s)
- John You En Chan
- Engineering Product Development, Singapore University of Technology and Design, Singapore487372, Singapore
| | - Qifeng Ruan
- Engineering Product Development, Singapore University of Technology and Design, Singapore487372, Singapore
- Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System, Harbin Institute of Technology (Shenzhen), Shenzhen518055, People's Republic of China
| | - Hongtao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore487372, Singapore
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore117583, Singapore
| | - Hao Wang
- Engineering Product Development, Singapore University of Technology and Design, Singapore487372, Singapore
| | - Hailong Liu
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore138634, Singapore
| | - Zhiyuan Yan
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore117583, Singapore
| | - Cheng-Wei Qiu
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore117583, Singapore
| | - Joel K W Yang
- Engineering Product Development, Singapore University of Technology and Design, Singapore487372, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore138634, Singapore
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21
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Su X, Dong Z, Wu J, Chi D, Loh XJ. Celebrating 25 Years of IMRE: Research Highlights on Nanomaterials and Nanotechnologies. ACS NANO 2022; 16:11492-11497. [PMID: 35904455 DOI: 10.1021/acsnano.2c06830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The Institute of Materials Research and Engineering (IMRE) is a research institute of the Science and Engineering Research Council (SERC), Agency for Science, Technology and Research (A*STAR). IMRE was established in September 1997. Over the past 25 years, IMRE has developed core competencies and interdisciplinary teams for material development from fundamental discoveries to industrial translation. Currently, with over 400 researchers and state-of-the-art research facilities, IMRE conducts world class research in important material and material technology fields, including polymer composites, optical materials, electronic materials, soft materials, structural materials, energy materials, biomaterials, quantum technologies, as well as advanced characterization. As a material-centered research institute in Singapore, IMRE has played important roles in pushing science boundaries and developing cutting-edge technologies. One of the key strategies is to partner international organizations, research institutes, and industry to fulfill its vision to be a leading research institute to accelerate materials research, moving from "Made in Singapore" toward "Created in Singapore".
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Affiliation(s)
- Xiaodi Su
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634
- Department of Chemistry, National University of Singapore, 9 Engineering Drive 1, Singapore 117543
| | - Zhaogang Dong
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576
| | - Jing Wu
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634
| | - Dongzhi Chi
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634
| | - Xian Jun Loh
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Singapore 138634
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22
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Zheng X, Yang J, Wang R, Lan T. Visible light waveband Dammann grating based on all-dielectric metasurface. APPLIED OPTICS 2022; 61:2184-2191. [PMID: 35333232 DOI: 10.1364/ao.448192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 02/05/2022] [Indexed: 06/14/2023]
Abstract
Dammann gratings (DGs) can generate a spot array in a particular arrangement. In recent years, DGs have been used in many fields such as laser beam splitting and optical coupling. Nanograting encoding technology can achieve a high signal-to-noise ratio and high-efficiency diffraction distribution; it also provides new design ideas for realizing the miniaturization and deviceization of DGs. In this work, we have comprehensively studied the DG based on an all-dielectric metasurface, which can produce a 5×5 diffraction spot array with a diffraction angle of 20∘×20∘. In an operation waveband from 650 to 690 nm, the DG has superior performance with high efficiency ≥60%; meanwhile, it achieves a relative low contrast ratio ≤0.33. Owing to high efficiency, wide waveband performance, and polarization insensitive property, the all-dielectric metasurface DG can provide possibilities for various application, including laser technology and optical information processing.
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23
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Ruan Q, Zhang W, Wang H, Chan JYE, Wang H, Liu H, Fan D, Li Y, Qiu CW, Yang JKW. Reconfiguring Colors of Single Relief Structures by Directional Stretching. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108128. [PMID: 34799881 DOI: 10.1002/adma.202108128] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/08/2021] [Indexed: 06/13/2023]
Abstract
Color changes can be achieved by straining photonic crystals or gratings embedded in stretchable materials. However, the multiple repeat units and the need for a volumetric assembly of nanostructures limit the density of information content. Inspired by surface reliefs on oracle bones and music records as a means of information archival, here, surface-relief elastomers are endowed with multiple sets of information that are accessible by mechanical straining along in-plane axes. Distinct from Bragg diffraction effects from periodic structures, trenches that generate color due to variations in trench depth, enabling individual trench segments to support a single color, are reported. Using 3D printed cuboids, trenches of varying geometric parameters are replicated in elastomers. These parameters determine the initial color (or lack thereof), the response to capillary forces, and the appearance when strained along or across the trenches. Strain induces modulation in trench depth or the opening and closure of a trench, resulting in surface reliefs with up to six distinct states, and an initially featureless surface that reveals two distinct images when stretched along different axes. The highly reversible structural colors are promising in optical data archival, anti-counterfeiting, and strain-sensing applications.
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Affiliation(s)
- Qifeng Ruan
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Wang Zhang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Hao Wang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - John You En Chan
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
| | - Hongtao Wang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
- Singapore Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Hailong Liu
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
| | - Dianyuan Fan
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China
| | - Ying Li
- SZU-NUS Collaborative Innovation Center for Optoelectronic Science & Technology, International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education, Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China
| | - Cheng-Wei Qiu
- Singapore Department of Electrical and Computer Engineering, National University of Singapore, Singapore, 117583, Singapore
| | - Joel K W Yang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore, 138634, Singapore
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24
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Ho IL. K-series approximation of vectorial optical fields for designing diffractive optical elements with subwavelength feature sizes. OPTICS EXPRESS 2021; 29:37211-37224. [PMID: 34808798 DOI: 10.1364/oe.435583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/12/2021] [Indexed: 06/13/2023]
Abstract
Diffractive optical elements (DOEs) are widely applied as compact solutions for desired light manipulations via wavefront shaping. Recent advanced chip applications further require their feature sizes to move down to the subwavelength, which inevitably brings forth vectorial effects of optical fields and makes the typical scalar-based theory invalid. However, simulating and optimizing their vectorial fields, which are associated with billions of adjustable parameters in the optical element, are difficult to do, because of the issues of numerical stability and the highly-demanding computational cost. To address this problem, this research proposes an applicable algorithm by means of a wave-vector (k) series approximation of vectorial optical fields. On the basis of the semi-analytical rigorous coupled wave analysis (RCWA), an adequate selection scheme on k-series enables computationally efficient yet still predictive calculations for DOEs. The performance estimations for exemplary designs by the finite difference time domain (FDTD) method show that the predicted intensity profiles by the proposed algorithm agree with the target by just a fractional error. Together with optimizing the geometrical degrees of freedom (e.g., DOE depth h) as compensation for errors from the truncation of k-series, the algorithm demonstrates its outperformance by one or two orders of magnitude in accuracy versus the scalar-based model, and demands only a reasonable computational resource.
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25
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Abstract
Abstract
3D printing belongs to the emerging technologies of our time. Describing diverse specific techniques, 3D printing enables rapid production of individual objects and creating shapes that would not be produced with other techniques. One of the drawbacks of typical 3D printing processes, however, is the layered structure of the created parts. This is especially problematic in the production of optical elements, which in most cases necessitate highly even surfaces. To meet this challenge, advanced 3D printing techniques as well as other sophisticated solutions can be applied. Here, we give an overview of 3D printed optical elements, such as lenses, mirrors, and waveguides, with a focus on freeform optics and other elements for which 3D printing is especially well suited.
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Affiliation(s)
- Tomasz Blachowicz
- Silesian University of Technology, Institute of Physics – Center for Science and Education , 44-100 Gliwice , Poland
| | - Guido Ehrmann
- Virtual Institute of Applied Research on Advanced Materials (VIARAM) , 33619 Bielefeld , Germany
| | - Andrea Ehrmann
- Bielefeld University of Applied Sciences, Faculty of Engineering and Mathematics , 33619 Bielefeld , Germany
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26
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Wang H, Ruan Q, Wang H, Rezaei SD, Lim KTP, Liu H, Zhang W, Trisno J, Chan JYE, Yang JKW. Full Color and Grayscale Painting with 3D Printed Low-Index Nanopillars. NANO LETTERS 2021; 21:4721-4729. [PMID: 34019769 DOI: 10.1021/acs.nanolett.1c00979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Sculpting nanostructures into different geometries in either one or two dimensions produces a wide range of colorful elements in microscopic prints. However, achieving different shades of gray and control of color saturation remain challenging. Here, we report a complete approach to color and grayscale generation based on the tuning of a single nanostructure geometry. Through two-photon polymerization lithography, we systematically investigated color generation from the basic single nanopillar geometry in low-refractive-index (n < 1.6) material. Grayscale and full color palettes were achieved that allow decomposition onto hue, saturation, and brightness values. This approach enabled the "painting" of arbitrary colorful and grayscale images by mapping desired prints to precisely controllable parameters during 3D printing. We further extend our understanding of the scattering properties of the low-refractive-index nanopillar to demonstrate grayscale inversion and color desaturation and steganography at the level of single nanopillars.
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Affiliation(s)
- Hao Wang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Qifeng Ruan
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Hongtao Wang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Soroosh Daqiqeh Rezaei
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Kevin T P Lim
- Cavendish Laboratory, JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Hailong Liu
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Wang Zhang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Jonathan Trisno
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - John You En Chan
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
| | - Joel K W Yang
- Engineering Product Development Pillar, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03 Innovis, Singapore 138634, Singapore
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27
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Jiang M, Song S, Li Y, Zeng X, Zhu L, Zhang M, Wang S, Li X, Cao Y. 3D high precision laser printing of a flat nanofocalizer for subwavelength light spot array. OPTICS LETTERS 2021; 46:356-359. [PMID: 33449028 DOI: 10.1364/ol.413302] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Here, we demonstrate a flat nanofocalizer for converging light field into a uniform subwavelength light spot array based on the fractional Talbot effect by developing a direct laser writing technique with 3D fabrication precision. The fractional Talbot effect endows the device with the merits of high compression ratio and modular design capability for transforming a plane wave into arrayed light focal spots. By combining a synergistic laser printing technique, we introduce a buffer layer for improving the fabrication precision of structural height in favor of accurately manipulating the phase delay. For a given light wavelength at 750 nm, by precisely producing a nanofocalizer consisting of periodic unit elements with the dimensions of 300(width)×600(length)×585(height)nm, we have achieved 5×6 light spot array with modular design, while the full width at half-maximum of a single focused light spot can be reduced to ∼0.82λ. Our research may pave the way for realizing subwavelength optical devices capable of being readily integrated to existing optical systems.
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28
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Structural multi-colour invisible inks with submicron 4D printing of shape memory polymers. Nat Commun 2021; 12:112. [PMID: 33397969 PMCID: PMC7782480 DOI: 10.1038/s41467-020-20300-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/19/2020] [Indexed: 01/30/2023] Open
Abstract
Four-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.
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