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Esmail MSM, Hameed MFO, Obayya SSA, Younis BM. Asymmetric dual-core liquid crystal channel-based tunable mode converter. Sci Rep 2024; 14:5239. [PMID: 38438521 PMCID: PMC10912772 DOI: 10.1038/s41598-024-55609-1] [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: 11/20/2023] [Accepted: 02/26/2024] [Indexed: 03/06/2024] Open
Abstract
In this work, a higher order-to-fundamental mode converter is reported and analyzed based on an asymmetric dual channel waveguide (ADC-WG) on silicon. In the reported structure, one of the two waveguides is infiltrated with nematic liquid crystal (NLC) material to add temperature tunability while the other one is a solid BK7 waveguide. The modal characteristics are obtained using the full vectorial finite difference method (FVFDM). In addition, the structural parameters and optical characteristics of the employed materials are investigated to achieve good wavelength selectivity with a short device length (LD). Thus, a compact mode converter that can work at different wavelengths including the telecommunication wavelength i.e., 1.55 μm with LD ~ 482.31 μm and a low crosstalk of - 19.86 dB is presented. To prove the thermal tunability of the suggested mode converter, its operation is tested through a temperature range between 20 and 35 °C and the results show that the mode conversion process is achieved at each temperature with different phase matching wavelengths (λPMW) but with quite similar coupling length (LC). The proposed device can therefore be effectively utilized in integrated photonic circuits.
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Affiliation(s)
- Mohamed Saleh Mohamed Esmail
- Basic Science Department, Faculty of Engineering, Misr University for Science and Technology, Giza, 12588, Egypt
| | - Mohamed Farhat O Hameed
- Center for Nanotechnology, Zewail City of Science, Technology and Innovation, October Gardens, 6th of October City, Giza, 12578, Egypt.
- Nanotechnology and Nanoelectronics Engineering Program, Zewail City of Science, Technology and Innovation, October Gardens, 6th of October City, Giza, 12578, Egypt.
| | - Salah S A Obayya
- Centre for Photonics and Smart Materials, Zewail City of Science, Technology and Innovation, October Gardens, 6th of October City, Giza, 12578, Egypt.
| | - B M Younis
- Centre for Photonics and Smart Materials, Zewail City of Science, Technology and Innovation, October Gardens, 6th of October City, Giza, 12578, Egypt
- Department of Electronics and Communications Engineering, Misr Higher Institute for Engineering and Technology (MET), Mansoura, Egypt
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Ertman S, Orzechowski K, Rutkowska K, Kołodyńska O, Różycka J, Ignaciuk A, Wasilewska N, Osuch T, Woliński TR. Periodic liquid crystalline waveguiding microstructures. Sci Rep 2023; 13:13896. [PMID: 37626152 PMCID: PMC10457291 DOI: 10.1038/s41598-023-41255-6] [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: 05/30/2023] [Accepted: 08/23/2023] [Indexed: 08/27/2023] Open
Abstract
Different methods allowing for creating optical waveguides with liquid-crystal (LC) cores, in which molecules form periodic patterns with precisely controlled periods, are reported. The first one is based on reversible photoalignment with high-resolution selective illumination and allows to control the period of LC molecules inside silica microcapillaries. The second method employs microstructures formed in PDMS, allowing to obtain both: LC-core waveguides and a set of specially designed periodic microelectrodes used for the periodic reorientation of molecules. Using both methods, we successfully controlled the period of the patterned alignment in the range from about 500 µm and scaled it down to as small as 20 µm. We performed experimental studies on waveguiding phenomenon in such structures, in view to obtain transmission spectra typical to optical fiber gratings. Since the results achieved in experimental conditions differed from those expected, the additional numerical simulations were performed to explain the observed effects. Finally, we obtained the waveguiding in a blue phase LC, characterized by naturally created three-dimensional periodicity with periods smaller than one micrometer. In such a structure, we were able to observe first-order bandgap, and moreover, we were able to tune it thermally in nearly the whole visible spectral range.
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Affiliation(s)
- Sławomir Ertman
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland.
| | - Kamil Orzechowski
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Katarzyna Rutkowska
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Oliwia Kołodyńska
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Julia Różycka
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Adam Ignaciuk
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Natalia Wasilewska
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
| | - Tomasz Osuch
- Faculty of Electronics and Information Technology, Institute of Electronic Systems, Warsaw University of Technology, Nowowiejska 15/19, 00-665, Warsaw, Poland
| | - Tomasz R Woliński
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662, Warsaw, Poland
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Zhang SY, Wang YF, Shen D, Luo DB, Zheng ZG. Deflecting and routing nematicons via orientation programmable liquid crystal array. OPTICS EXPRESS 2023; 31:20955-20964. [PMID: 37381207 DOI: 10.1364/oe.486203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/15/2023] [Indexed: 06/30/2023]
Abstract
By designing a liquid crystal cell with comb electrode structure, the alignment modulation of nematic liquid crystal in the cell can be realized after the electric field is applied. In different orientation regions, the incident laser beam can deflect at different angles. At the same time, by changing the incident angle of the laser beam, the reflection modulation of the laser beam on the interface of the liquid crystal molecular orientation change can be realized. Based on the above discussion, we then demonstrate the modulation of liquid crystal molecular orientation arrays on nematicon pairs. In different orientation regions of liquid crystal molecules, nematicon pairs can exhibit various combinations of deflections, and these deflection angles are modulable under external fields. Deflection and modulation of nematicon pairs have potential applications in optical routing and optical communication.
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Optical Filters Based on Cholesteric, Blue and Sphere Mesophases. Polymers (Basel) 2022; 14:polym14224898. [PMID: 36433026 PMCID: PMC9694172 DOI: 10.3390/polym14224898] [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: 10/13/2022] [Revised: 11/02/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
An optical filter is one of the indispensable devices in massive and high-speed communication, optical signal processing, and display. Twist-structure liquid crystals, cholesteric liquid crystals, blue-phase liquid crystals, and sphere-phase liquid crystals show potential application in optical filters originating from the periodic nanostructures. Wavelength and bandwidth tuning can be controlled via temperature, electric fields, light, angle, spatial control, and templating technology. In this review, we discuss the recent developments of twist-structure liquid crystal filters.
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Ayriyan A, Ayryan EA, Egorov AA, Timko M, Kopčanský P. Properties of liquid-crystal wave-guiding structures. SOFT MATTER 2022; 18:7441-7451. [PMID: 36134729 DOI: 10.1039/d2sm00597b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The paper presents the results of an experimental and numerical study of some properties of multimode liquid crystal waveguide structures. The nematic 4-cyano-4'-pentylbiphenyl (5CB) was used as a liquid crystal. A description of the experiments performed and some of the techniques used are given. Scattering diagrams are presented that characterize the features of propagation in a multimode liquid-crystal waveguide of one and many modes. It is shown that when an external repetitively pulsed electric field is switched on, the attenuation and size of inhomogeneities decrease. To explain this effect, the classical theory of liquid crystal director fluctuations is used. For the first time some properties of a liquid-crystal waveguide are described with explicit allowance for the two-dimensional Frederiks model. The two-dimensional nature of the liquid crystal director reorientation effects in our case (including under the action of an electric impulse-periodic field) required the involvement of the three-dimensional theory of light scattering in an LC waveguide and, as a consequence, the study of two-dimensional scattering diagrams in experiments, which make it possible to consider the two-dimensional nature of the behavior of the LC director. The relevance and importance of such studies are related both to the practical use and prospects of using liquid crystal materials in various high-speed and low-energy integrated-optical devices, for example, in communication elements, modulators, and sensors.
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Affiliation(s)
- A Ayriyan
- Meshcheryakov Laboratory of Information Technologies, JINR, Dubna, 6 Joliot-Curie Str., 141980, Russia
- IT and Computing Division, A. Alikhanyan National Laboratory, 2 Alikhanian Brothers Str., 0036, Yerevan, Armenia
- Dubna State University, 19 Universitetskaya Str., Dubna, 141980, Russia
| | - E A Ayryan
- Meshcheryakov Laboratory of Information Technologies, JINR, Dubna, 6 Joliot-Curie Str., 141980, Russia
- Dubna State University, 19 Universitetskaya Str., Dubna, 141980, Russia
| | - A A Egorov
- Popov Moscow Society for Radioengineering, Electronics and Communications, 2 Sretenskii Blv., Moscow, 101000, Russia.
| | - M Timko
- Institute of Experimental Physics, Slovak Academy of Sciences, 47 Watsonova str., Košice, 04001, Slovakia
| | - P Kopčanský
- Institute of Experimental Physics, Slovak Academy of Sciences, 47 Watsonova str., Košice, 04001, Slovakia
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Rutkowska KA, Sobotka P, Grom M, Baczyński S, Juchniewicz M, Marchlewicz K, Dybko A. A Novel Approach for the Creation of Electrically Controlled LC:PDMS Microstructures. SENSORS 2022; 22:s22114037. [PMID: 35684658 PMCID: PMC9185514 DOI: 10.3390/s22114037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023]
Abstract
This work presents research on unique optofluidic systems in the form of air channels fabricated in PDMS and infiltrated with liquid crystalline material. The proposed LC:PDMS structures represent an innovative solution due to the use of microchannel electrodes filled with a liquid metal alloy. The latter allows for the easy and dynamic reconfiguration of the system and eliminates technological issues experienced by other research groups. The paper discusses the design, fabrication, and testing methods for tunable LC:PDMS structures. Particular emphasis was placed on determining their properties after applying an external electric field, depending on the geometrical parameters of the system. The conclusions of the performed investigations may contribute to the definition of guidelines for both LC:PDMS devices and a new class of potential sensing elements utilizing polymers and liquid crystals in their structures.
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Affiliation(s)
- Katarzyna A. Rutkowska
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; (P.S.); (M.G.); (S.B.)
- Correspondence:
| | - Piotr Sobotka
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; (P.S.); (M.G.); (S.B.)
| | - Monika Grom
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; (P.S.); (M.G.); (S.B.)
| | - Szymon Baczyński
- Faculty of Physics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland; (P.S.); (M.G.); (S.B.)
| | - Marcin Juchniewicz
- Centre for Advanced Materials and Technologies (CEZAMAT), Warsaw University of Technology, Poleczki 19, 02-822 Warsaw, Poland;
| | - Kasper Marchlewicz
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland; (K.M.); (A.D.)
| | - Artur Dybko
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland; (K.M.); (A.D.)
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Special Issue on Light Beams in Liquid Crystals. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The study of propagating light beams in liquid crystals, i [...]
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