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Ganazhapa B, Pereiro-García J, Arregui XQ, Geday MA, Guadaño G, Caño-García M. Generation of arbitrarily patterned polarizers using 2-photon polymerization. Sci Rep 2024; 14:22550. [PMID: 39343947 DOI: 10.1038/s41598-024-73946-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 09/23/2024] [Indexed: 10/01/2024] Open
Abstract
Patterned polarizers are prepared using liquid crystals (LC) doped with a black dichroic dye and in combination with a linear polarizer. The pattern is achieved with a nanostructured LC alignment surface, that is generated using a two-photon polymerization direct laser write (2PP-DLW). This technique creates a pattern of high-resolution grooves in the photoresist at any arbitrary angle. The angle governs the LC orientation at any substrate surface point, determining the transmitted light linear polarization angle. This paper presents the first use of a 2PP-DLW cured positive tone photoresist for dichroic dye-doped LC alignment. Two complementary photoresists have been employed: conventional negative tone SU-8 photoresist and, in this context novel, positive tone S1805 photoresist. The alignment quality of the polarizers has been assessed by analyzing the transmission using an additional polarizer. For SU-8, the resulting grayscale pattern and a contrast ratio (CR) of 14 has measured. The uniformity of the alignment has been measured to be 65% using normalized Shannon entropy (H). For S1805, a CR of 37 was measured, and a uniformity of 63% was obtained. 2PP-DLW allows for shaping complex patterns in submicron dimensions and for the fabrication of arbitrarily patterned polarizers and other LC devices.
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Affiliation(s)
- Byron Ganazhapa
- CEMDATIC, ETSI Telecomunicación, Universidad Politécnica de Madrid, Av. Complutense 30, Madrid, 28040, Spain.
- LASING S.A, c/Julián Camarillo, 26, Madrid, 28037, Spain.
| | - Javier Pereiro-García
- CEMDATIC, ETSI Telecomunicación, Universidad Politécnica de Madrid, Av. Complutense 30, Madrid, 28040, Spain
| | - Xabier Quintana Arregui
- CEMDATIC, ETSI Telecomunicación, Universidad Politécnica de Madrid, Av. Complutense 30, Madrid, 28040, Spain
| | - Morten Andreas Geday
- CEMDATIC, ETSI Telecomunicación, Universidad Politécnica de Madrid, Av. Complutense 30, Madrid, 28040, Spain
| | | | - Manuel Caño-García
- CEMDATIC, ETSI Telecomunicación, Universidad Politécnica de Madrid, Av. Complutense 30, Madrid, 28040, Spain
- Department of Electronics and Computer Technology, Research Centre for Information and Communication Technologies (CITIC-UGR), University of Granada, Granada, Spain
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Sit A, Di Colandrea F, D'Errico A, Karimi E. Genetic algorithm for the response of arbitrarily twisted nematic liquid crystals to an applied field. Phys Rev E 2024; 109:054705. [PMID: 38907444 DOI: 10.1103/physreve.109.054705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/18/2024] [Indexed: 06/24/2024]
Abstract
When an external field is applied across a liquid-crystal cell, the twist and tilt distributions cannot be calculated analytically and must be extracted numerically. In the standard approach, the Euler-Lagrange equations are derived from the minimization of the free energy of the system and then solved via finite-difference methods, often implemented in commercial software. These tools iterate from initial solutions that are compatible with the boundary conditions, providing limited to no flexibility for customization. Here we present a genetic algorithm that outputs fast and accurate solutions to the integral form of the equations. In our approach, the evolutionary routine is sequentially applied at each position within the bulk of the cell, thus overcoming the necessity of assuming trial solutions. The full range of twist angles from -90^{∘} to 90^{∘} is considered. In this way, the predictions of our routine strongly support the experimentally observed polarization transformations of light incident on different spatially varying twisted nematic liquid-crystal cells, patterned with different topologies on the two alignment layers.
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Interference Spectral Imaging Based on Liquid Crystal Relaxation and Its Application in Optical Component Defect Detection. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12020718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In this paper, we propose a fast interference spectral imaging system based on liquid crystal (LC) relaxation. The path delay of nematic LC during falling relaxation is used for the scanning of the optical path. Hyperspectral data can be obtained by Fourier transforming the data according to the path delay. The system can obtain two-dimensional spatial images of arbitrary wavelengths in the range of 300–1100 nm with a spectral resolution of 262 cm−1. Compared with conventional Fourier transform spectroscopy, the system can easily collect and integrate all valid information within 20 s. Based on the LC, controlling the optical path difference between two orthogonally polarized beams can avoid mechanical movement. Finally, the potential for application in contactless and rapid non-destructive optical component defect inspection is demonstrated.
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Del Pozo M, Sol JAHP, Schenning APHJ, Debije MG. 4D Printing of Liquid Crystals: What's Right for Me? ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2104390. [PMID: 34716625 DOI: 10.1002/adma.202104390] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/20/2021] [Indexed: 05/24/2023]
Abstract
Recent years have seen major advances in the developments of both additive manufacturing concepts and responsive materials. When combined as 4D printing, the process can lead to functional materials and devices for use in health, energy generation, sensing, and soft robots. Among responsive materials, liquid crystals, which can deliver programmed, reversible, rapid responses in both air and underwater, are a prime contender for additive manufacturing, given their ease of use and adaptability to many different applications. In this paper, selected works are compared and analyzed to come to a didactical overview of the liquid crystal-additive manufacturing junction. Reading from front to back gives the reader a comprehensive understanding of the options and challenges in the field, while researchers already experienced in either liquid crystals or additive manufacturing are encouraged to scan through the text to see how they can incorporate additive manufacturing or liquid crystals into their own work. The educational text is closed with proposals for future research in this crossover field.
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Affiliation(s)
- Marc Del Pozo
- Laboratory for Stimuli-Responsive Functional Materials & Devices (SFD), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology (TU/e), Groene Loper 3, Eindhoven, 5612 AE, The Netherlands
| | - Jeroen A H P Sol
- Laboratory for Stimuli-Responsive Functional Materials & Devices (SFD), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology (TU/e), Groene Loper 3, Eindhoven, 5612 AE, The Netherlands
| | - Albert P H J Schenning
- Laboratory for Stimuli-Responsive Functional Materials & Devices (SFD), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology (TU/e), Groene Loper 3, Eindhoven, 5612 AE, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Groene Loper 3, Eindhoven, 5612 AE, The Netherlands
| | - Michael G Debije
- Laboratory for Stimuli-Responsive Functional Materials & Devices (SFD), Department of Chemical Engineering and Chemistry, Eindhoven University of Technology (TU/e), Groene Loper 3, Eindhoven, 5612 AE, The Netherlands
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Li Y, Yang Z, Chen R, Mo L, Li J, Hu M, Wu ST. Submillisecond-Response Polymer Network Liquid Crystal Phase Modulators. Polymers (Basel) 2020; 12:polym12122862. [PMID: 33265934 PMCID: PMC7760688 DOI: 10.3390/polym12122862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 11/27/2020] [Accepted: 11/27/2020] [Indexed: 11/22/2022] Open
Abstract
A submillisecond-response and light scattering-free polymer-network liquid crystal (PNLC) for infrared spatial light modulators is demonstrated. Our new liquid crystal host exhibits a higher birefringence, comparable dielectric anisotropy, and slightly lower visco-elastic constant than a commonly employed commercial material, HTG-135200. Moreover, the electro-optical performance of our PNLCs with different monomer concentrations, cell gaps, and liquid crystal (LC) hosts is compared and discussed from four aspects: operating voltage, hysteresis, relaxation time, and light scattering loss. The temperature effect on hysteresis is also analyzed. Potential applications of PNLCs for laser beam steering and spatial light modulators especially in the infrared region are foreseeable.
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Affiliation(s)
- Yannanqi Li
- College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA; (Y.L.); (Z.Y.)
| | - Zhiyong Yang
- College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA; (Y.L.); (Z.Y.)
| | - Ran Chen
- Key Laboratory of Applied Surface and Colloid Chemistry, School of Materials Science and Engineering, Shaanxi Normal University, Xi’an 710065, China;
| | - Lingchao Mo
- Optical and Electrical Material Center, Xi’an Modern Chemistry Research Institute, Xi’an 710065, China; (L.M.); (J.L.)
| | - Juanli Li
- Optical and Electrical Material Center, Xi’an Modern Chemistry Research Institute, Xi’an 710065, China; (L.M.); (J.L.)
| | - Minggang Hu
- Optical and Electrical Material Center, Xi’an Modern Chemistry Research Institute, Xi’an 710065, China; (L.M.); (J.L.)
- Correspondence: (M.H.); (S.-T.W.); Tel.: +1-407-823-4763 (S.-T.W.)
| | - Shin-Tson Wu
- College of Optics and Photonics, University of Central Florida, Orlando, FL 32816, USA; (Y.L.); (Z.Y.)
- Correspondence: (M.H.); (S.-T.W.); Tel.: +1-407-823-4763 (S.-T.W.)
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Yang JP, Wu FY, Wang PS, Chen HMP. Characterization of the spatially anamorphic phenomenon and temporal fluctuations in high-speed, ultra-high pixels-per-inch liquid crystal on silicon phase modulator. OPTICS EXPRESS 2019; 27:32168-32183. [PMID: 31684434 DOI: 10.1364/oe.27.032168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 10/02/2019] [Indexed: 06/10/2023]
Abstract
High-birefringence liquid crystal (LC) in ultrathin LCOS panels was adopted to prepare high phase precision (mSTD =λ/50) and phase accuracy (mAPAE% ∼8%) with suppressed pixel-level crosstalk effects. In conjunction with optimized digital driving scheme, the zero order light loss was found directly related to the phase accuracy error. Meanwhile, the world's fastest pure phase modulation LCOS with a response time of ∼0.87 ms at 45 °C was also achieved. The low-temporal flicker (P-P ∼2.0%) with high-speed LC responses was demonstrated by applying new digital driving scheme. Finally, the 4K2 K LCOS-SLM (∼7000 PPI) was evaluated its difficulties and opportunities.
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Liquid Crystal Beam Steering Devices: Principles, Recent Advances, and Future Developments. CRYSTALS 2019. [DOI: 10.3390/cryst9060292] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Continuous, wide field-of-view, high-efficiency, and fast-response beam steering devices are desirable in a plethora of applications. Liquid crystals (LCs)—soft, bi-refringent, and self-assembled materials which respond to various external stimuli—are especially promising for fulfilling these demands. In this paper, we review recent advances in LC beam steering devices. We first describe the general operation principles of LC beam steering techniques. Next, we delve into different kinds of beam steering devices, compare their pros and cons, and propose a new LC-cladding waveguide beam steerer using resistive electrodes and present our simulation results. Finally, two future development challenges are addressed: Fast response time for mid-wave infrared (MWIR) beam steering, and device hybridization for large-angle, high-efficiency, and continuous beam steering. To achieve fast response times for MWIR beam steering using a transmission-type optical phased array, we develop a low-loss polymer-network liquid crystal and characterize its electro-optical properties.
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Meng C, Chen E, Wang L, Tang S, Tseng M, Guo J, Ye Y, Yan QF, Kwok H. Color-switchable liquid crystal smart window with multi-layered light guiding structures. OPTICS EXPRESS 2019; 27:13098-13107. [PMID: 31052839 DOI: 10.1364/oe.27.013098] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
We propose here a novel multi-layered waveguide liquid crystal (LC) smart window with full color rendering based on a polymer-network liquid crystal system. The inserted position of three-primary-color LED light bars is specially designed, which is parallel to the LC alignment to obtain a higher difference between transparent and scattering states. The optimal matching of polymer-network LC system is experimentally achieved by comparing several groups of LC and reactive mesogen materials. The prepared smart window is measured and analyzed in detail including optical/chromatic test, morphology characterization, and actual application effect. The proposed architecture opens up new prospects of flexible color switchable ability and synchronized full-color display for smart windows without limitations of slow LC response time and complicated field sequential driving scheme.
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He Z, Tan G, Chanda D, Wu ST. Novel liquid crystal photonic devices enabled by two-photon polymerization [Invited]. OPTICS EXPRESS 2019; 27:11472-11491. [PMID: 31052991 DOI: 10.1364/oe.27.011472] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 03/21/2019] [Indexed: 06/09/2023]
Abstract
In addition to displays, liquid crystals (LCs) have also found widespread applications in photonic devices, such as adaptive lens, adaptive optics, and sensors, because of their responses to electric field, temperature, and light. As the fabrication technique advances, more sophisticated devices can be designed and created. In this review, we report recent advances of two-photon polymerization-based direct-laser writing enabled LC devices. Firstly, we describe the basic working principle of two-photon polymerization. With this powerful fabrication technique, we can generate anchoring energy by surface morphology to align LC directors on different form factors. To prove this concept, we demonstrate LC alignment on planar, curvilinear surfaces as well as in three-dimensional volumes. Based on the results, we further propose a novel, ultra-broadband, twisted-nematic diffractive waveplate that can potentially be fulfilled by this technique. Next, we briefly discuss the current status of direct-laser writing on LC reactive mesogens and its potential applications. Finally, we present two design challenges: fabrication yield and polymer relaxation/deformation, remaining to be overcome.
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He Z, Lee YH, Chen R, Chanda D, Wu ST. Switchable Pancharatnam-Berry microlens array with nano-imprinted liquid crystal alignment. OPTICS LETTERS 2018; 43:5062-5065. [PMID: 30320819 DOI: 10.1364/ol.43.005062] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/14/2018] [Indexed: 06/08/2023]
Abstract
We report a rapid nano-imprinting technique to pattern the liquid crystal alignment of a Pancharatnam-Berry phase microlens array. Through implementing a single-side aligned cell, we demonstrate a switchable microlens array with fast response time and low operation voltage. Further investigation of focusing property as well as imaging capability ensure the good quality of the microlens array. Besides planar structures, this method is also promising for patterning liquid crystal alignment on curvilinear surfaces.
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He Z, Lee YH, Chanda D, Wu ST. Adaptive liquid crystal microlens array enabled by two-photon polymerization. OPTICS EXPRESS 2018; 26:21184-21193. [PMID: 30119422 DOI: 10.1364/oe.26.021184] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
A tunable-focus liquid crystal microlens array is demonstrated and characterized. Using two-photon polymerization based direct-laser writing, a polymerized microlens array is fabricated on one substrate. Such a microlens array creates inhomogeneous electric field distribution and homogeneous-like liquid-crystal alignment, simultaneously. The phase profile and thus the focal length can be tuned dynamically by the applied voltage. We also further investigate the focusing property and the imaging capability of the fabricated sample. Using the adaptive microlens array as an example, we demonstrate that directly forming a curvilinear surface with liquid-crystal alignment is feasible. In addition to adaptive lens, this direct-laser writing method is also a powerful tool for making other tunable photonic devices.
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