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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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Jagodič U, Vellaichamy M, Škarabot M, Muševič I. Surface alignment of nematic liquid crystals by direct laser writing of photopolymer alignment layers. LIQUID CRYSTALS 2023; 50:1999-2009. [PMID: 38352915 PMCID: PMC10860699 DOI: 10.1080/02678292.2023.2242297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/25/2023] [Indexed: 02/16/2024]
Abstract
We demonstrate the fabrication of good quality surface alignment layers on glass by Direct Laser Writing method using a 2-photon polymerisation technique. We use commercially available photosensitive resins to print alignment layers by scanning the focal point of a femtosecond laser near the resin-glass interface. This results in down to ~ 100 nm thin alignment layers that provide good planar anchoring of 5CB and MLC13300, with the easy axis of alignment along the scanning direction. The azimuthal anchoring strength is ~ 5 × 10-6 J/m2 and is an order of magnitude weaker compared to commercial rubbed polyimide alignment layer. The threshold voltage for Fréedericksz transition in a 90° twisted nematic cell is slightly increased compared to conventional rubbed polyimide for printed alignment layers. The turn-on switching time is longer for printed layers compared to polyimide alignment layers, whereas the turn-off time is shorter for printed alignment layers. The advantage of this new method is in its flexibility, as we demonstrate printing of complex surface alignment patterns with alignment layer thickness below 100 nm.
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Affiliation(s)
- Uroš Jagodič
- Condensed Matter Department, J. Stefan Institute, Ljubljana, Slovenia
| | | | - Miha Škarabot
- Condensed Matter Department, J. Stefan Institute, Ljubljana, Slovenia
| | - Igor Muševič
- Condensed Matter Department, J. Stefan Institute, Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana, Slovenia
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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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Electrically Tuneable Optical Diffraction Gratings Based on a Polymer Scaffold Filled with a Nematic Liquid Crystal. Polymers (Basel) 2021; 13:polym13142292. [PMID: 34301049 PMCID: PMC8309354 DOI: 10.3390/polym13142292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/10/2021] [Accepted: 07/10/2021] [Indexed: 11/28/2022] Open
Abstract
We present an experimental and theoretical investigation of the optical diffractive properties of electrically tuneable optical transmission gratings assembled as stacks of periodic slices from a conventional nematic liquid crystal (E7) and a standard photoresist polymer (SU-8). The external electric field causes a twist-type reorientation of the LC molecules toward a perpendicular direction with respect to initial orientation. The associated field-induced modification of the director field is determined numerically and analytically by minimization of the Landau–de Gennes free energy. The optical diffraction properties of the associated periodically modulated structure are calculated numerically on the basis of rigorous coupled-wave analysis (RCWA). A comparison of experimental and theoretical results suggests that polymer slices provoke planar surface anchoring of the LC molecules with the inhomogeneous surface anchoring energy varying in the range 5–20 μJ/m2. The investigated structures provide a versatile approach to fabricating LC-polymer-based electrically tuneable diffractive optical elements (DOEs).
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Bošnjaković D, Sebastián N, Drevenšek-Olenik I. Magnetically Tunable Liquid Crystal-Based Optical Diffraction Gratings. Polymers (Basel) 2020; 12:polym12102355. [PMID: 33066481 PMCID: PMC7602225 DOI: 10.3390/polym12102355] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/11/2020] [Accepted: 10/12/2020] [Indexed: 11/16/2022] Open
Abstract
We present a theoretical analysis of optical diffractive properties of magnetically tunable optical transmission gratings composed of periodically assembled layers of a polymer and a ferromagnetic liquid crystal (LC). The orientational structure of the LC layers as a function of an applied magnetic field is calculated by minimization of the Landau-de Gennes free energy for ferromagnetic LCs, which is performed numerically and also analytically by using the one-constant approximation and the approximations of the high and the low magnetic fields. Optical diffractive properties of the associated diffraction structure are calculated numerically in the framework of rigorous coupled-wave analysis (RCWA). The presented methodology provides a basis for designing new types of diffractive optical element based on ferromagnetic LCs and simulating their operation governed by the in-plane magnetic field.
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Affiliation(s)
- Dejan Bošnjaković
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia;
- Faculty of Electrical Engineering, Computer Science and Information Technology, Josip Juraj Strossmayer University of Osijek, Kneza Trpimira 2B, 31000 Osijek, Croatia
- Correspondence:
| | - Nerea Sebastián
- J. Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
| | - Irena Drevenšek-Olenik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia;
- J. Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia;
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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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Gao S, Fleisch M, Rupp RA, Cmok L, Medle-Rupnik P, Mertelj A, Lisjak D, Zhang X, Drevenšek-Olenik I. Magnetically tunable optical diffraction gratings based on a ferromagnetic liquid crystal. OPTICS EXPRESS 2019; 27:8900-8911. [PMID: 31052701 DOI: 10.1364/oe.27.008900] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Transmission optical diffraction gratings composed of periodic slices of a ferromagnetic liquid crystal and a conventional photoresist polymer are demonstrated. Dependence of diffraction efficiencies of various diffraction orders on an in-plane external magnetic field is investigated. It is shown that diffraction properties can be effectively tuned by magnetic fields as low as a few mT. The tuning mechanism is explained in the framework of a simple empirical model and also by numerical simulations based on the rigorous coupled wave analysis (RCWA). The obtained results provide a proof of principle of operation of magnetically tunable liquid crystalline diffractive optical elements applicable in contactless schemes for control of optical signals.
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Coupling of Defect Modes in Cholesteric Liquid Crystals Separated by Isotropic Polymeric Layers. Polymers (Basel) 2018; 10:polym10070805. [PMID: 30960730 PMCID: PMC6403987 DOI: 10.3390/polym10070805] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/15/2018] [Accepted: 07/20/2018] [Indexed: 11/21/2022] Open
Abstract
Cholesteric liquid crystal structures with multiple isotropic defect layers exhibit localized optical modes (defect modes). Coupling effects between these modes were simulated using the finite difference time domain method. Analogous to the well-known result of the tight-binding approximation in solid state physics, splitting of the defect modes takes place, as soon as the structure contains more than one defect layer. The dispersion relation of the mini-bands forming within the photonic band gap of the structure is calculated numerically. The structures might have promising applications for multiwavelength filters and low-threshold lasers.
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Two-photon polymerization enabled multi-layer liquid crystal phase modulator. Sci Rep 2017; 7:16260. [PMID: 29176729 PMCID: PMC5701147 DOI: 10.1038/s41598-017-16596-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/15/2017] [Indexed: 11/08/2022] Open
Abstract
The performance of liquid crystal (LC) spatial light modulators depends critically on the amount of cumulative phase change. However, for regular phase modulators, a large phase change comes with a slow time response penalty. A multi-layer liquid crystal (LC) spatial light modulator offers a large phase change while keeping fast response time due to the decoupling between phase change and time response through engineered sub-micron scaffold. Here, we demonstrate specially designed 2- and 3-layer LC cells which can achieve 4 times and 7 times faster response time than that of conventional single-layer LC phase modulator of equivalent thickness, respectively. A versatile two-photon laser lithography is employed for LC cell scaffolding to accurately verify theoretical predictions with experimental measurements.
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Tartan CC, Salter PS, Wilkinson TD, Booth MJ, Morris S, Elston SJ. Generation of 3-dimensional polymer structures in liquid crystalline devices using direct laser writing. RSC Adv 2017. [DOI: 10.1039/c6ra25091b] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate laser writing of birefringent polymer structures with a controllable orientation of the optic axis in liquid crystal devices.
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Affiliation(s)
- C. C. Tartan
- Department of Engineering Science
- University of Oxford
- Oxford
- UK
| | - P. S. Salter
- Department of Engineering Science
- University of Oxford
- Oxford
- UK
| | | | - M. J. Booth
- Department of Engineering Science
- University of Oxford
- Oxford
- UK
| | - S. M. Morris
- Department of Engineering Science
- University of Oxford
- Oxford
- UK
| | - S. J. Elston
- Department of Engineering Science
- University of Oxford
- Oxford
- UK
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