Reflective liquid crystal polarization gratings with high efficiency and small pitch

2008 ◽  
Author(s):  
Ravi K. Komanduri ◽  
Chulwoo Oh ◽  
Michael J. Escuti
Keyword(s):  
Liquid Crystal ◽  
High Efficiency ◽  
Polarization Gratings ◽  
Small Pitch

High efficiency reflective liquid crystal polarization gratings

2009 ◽  
Vol 95 (9) ◽  
pp. 091106 ◽  
Author(s):  
R. K. Komanduri ◽  
M. J. Escuti
Keyword(s):  
Liquid Crystal ◽  
High Efficiency ◽  
Polarization Gratings

scholarly journals Enhancing the Optical Efficiency of Near-Eye Displays with Liquid Crystal Optics

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 107
Author(s):  
Tao Zhan ◽  
En-Lin Hsiang ◽  
Kun Li ◽  
Shin-Tson Wu
Keyword(s):  
Virtual Reality ◽  
Liquid Crystal ◽  
High Efficiency ◽  
Berry Phase ◽  
Optical Element ◽  
Liquid Crystal Polymer ◽  
Proof Of Concept ◽  
Optical Efficiency ◽  
Crystal Polymer ◽  
Light Efficiency

We demonstrate a light efficient virtual reality (VR) near-eye display (NED) design based on a directional display panel and a diffractive deflection film (DDF). The DDF was essentially a high-efficiency Pancharatnam-Berry phase optical element made of liquid crystal polymer. The essence of this design is directing most of the display light into the eyebox. The proposed method is applicable for both catadioptric and dioptric VR lenses. A proof-of-concept experiment was conducted with off-the-shelf optical parts, where the light efficiency was enhanced by more than 2 times.

scholarly journals Recent Advances in Photoalignment Liquid Crystal Polarization Gratings and Their Applications

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 900
Author(s):  
Tiegang Lin ◽  
Jin Xie ◽  
Yingjie Zhou ◽  
Yaqin Zhou ◽  
Yide Yuan ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Anisotropy ◽  
Review Paper ◽  
Fabrication Process ◽  
Polarization Gratings ◽  
High Diffraction Efficiency ◽  
Physical Principles ◽  
High Diffraction ◽  
Exposure Methods ◽  
Beam Split

Liquid crystal (LC) circular polarization gratings (PGs), also known as Pancharatnam–Berry (PB) phase deflectors, are diffractive waveplates with linearly changed optical anisotropy axes. Due to the high diffraction efficiency, polarization selectivity character, and simple fabrication process, photoalignment LC PGs have been widely studied and developed especially in polarization management and beam split. In this review paper, we analyze the physical principles, show the exposure methods and fabrication process, and present relevant promising applications in photonics and imaging optics.

scholarly journals Design of Tunable Holographic Liquid Crystalline Diffraction Gratings

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6789
Author(s):  
Katarzyna A. Rutkowska ◽  
Anna Kozanecka-Szmigiel
Keyword(s):  
Liquid Crystal ◽  
Communication Networks ◽  
Optical Communication ◽  
Liquid Crystalline ◽  
Incident Light ◽  
Diffraction Gratings ◽  
Lagrange Equations ◽  
Experimental Conditions ◽  
Molecular Distribution ◽  
Polarization Gratings

Tunable diffraction gratings and phase filters are important functional devices in optical communication and sensing systems. Polarization gratings, in particular, capable of redirecting an incident light beam completely into the first diffraction orders may be successfully fabricated in liquid crystalline cells assembled from substrates coated with uniform transparent electrodes and orienting layers that force a specific molecular distribution. In this work, the diffraction properties of liquid crystal (LC) cells characterized by a continually rotating cycloidal director pattern at the cell substrates and in the bulk, are studied theoretically by solving a relevant set of the Euler-Lagrange equations. The electric tunability of the gratings is analyzed by estimating the changes in liquid crystalline molecular distribution and thus in effective birefringence, as a function of external voltage. To the best of our knowledge, such detailed numerical calculations have not been presented so far for liquid crystal polarization gratings showing a cycloidal director pattern. Our theoretical predictions may be easily achieved in experimental conditions when exploiting, for example, photo-orienting material, to induce a permanent LC alignment with high spatial resolution. The proposed design may be for example, used as a tunable passband filter with adjustable bandwidths, thus allowing for potential applications in optical spectroscopy, optical communication networks, remote sensing and beyond.

scholarly journals ELECTRO-OPTICAL SWITCHING OF THE MAIN OPTICAL AXIS OF A FERROELECTRIC LIQUID CRYSTAL SPIRAL NANOSTRUCTUREIN A PLANAR-ORIENTED DISPLAY CELL

Doklady BGUIR ◽  
2019 ◽  
pp. 21-27
Author(s):  
E. P. Pozhidaev ◽  
T. P. Tkachenko ◽  
A. V. Kuznetsov ◽  
I. N. Kompanets
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Optical Switching ◽  
Optical Axis ◽  
Modulation Frequency ◽  
Light Transmittance ◽  
Weak Electric Field ◽  
Ferroelectric Liquid Crystal ◽  
Light Modulation ◽  
Small Pitch

In a known display cell with the nematic liquid crystal (NLC) and interdigital electrodes on one of the glass substrates, the “In-Plane Switching” (IPS) mode is implemented, in which the NLC main optical axis reorients in a plane parallel to substrates, providing the most correct color reproduction at different angles view, up to 178 ° horizontally and vertically. Unfortunately, the creation of interdigital metal electrodes complicates and increases the technological process cost and causes a decrease in image contrast. At the same time, experimental results and calculations based on classical electro-optics of crystals indicate that electrooptical switching in the IPS mode is a natural and intrinsic feature of a conventional (with continuous electrodes) display cell with a planar-oriented layer of the ferroelectric liquid crystal (FLC), in which the effect of the deformed (by the electric field) helix FLC nanostructure is realized (DHF effect). In such a cell, the reorientation of the main optical axis under the influence of a weak electric field also occurs in the substrate plane if the FLC has a small pitch (about 100 nm or less) and a large tilt angle of molecules in the layer (about 38 ° or more). The dependences of the FLC cell light transmittance measured in this work, confirmed the achievement of the IPS electro-optical mode in the DHF FLC cell; moreover, the light modulation frequency was 1 kHz. Thus, while maintaining all the advantages of the IPS mode known in NLC, its implementation in FLC allows additionally obtaining technological advantages and multiple increase in modulation frequency.

scholarly journals Mechanisms of Chiral Transfer in Optically Active Dopant – Nematic Liquid Crystal Systems

2020 ◽  
Vol 20 (4) ◽  
pp. 6-26
Author(s):  
V. A. Burmistrov ◽  
V. V. Aleksandriiskii ◽  
I. V. Novikov ◽  
O. I. Koifman
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
High Efficiency ◽  
Stationary Phases ◽  
Theoretical Description ◽  
Optically Active ◽  
Axial Coordination ◽  
Chiral Dopants

Induction of helical mesophases by incorporating chiral dopants into the nematics matrix is the promising modern trends in the chemistry of liquid crystals. This process is associated with a unique phenomenon - an amplification of chirality in liquid-crystalline phases, which ensures the detection of enantiomers by their chiral induction, much more sensitive than other methods. The relevance of this approach is due to the need to create perspective electro-optical devices operating with ultra-low control voltages based on twist effects, chromatographic stationary phases with high chiral selectivity, flexible magnets, photo-sensitive nanostructures, and other smart LC materials. The successful solution of these problems is impossible without experimental research and theoretical comprehension of the mechanisms of third level chiral transfer optically active dopant – nematic liquid crystal. In the last decade, a large number of works have appeared on the solution of these problems. This review is devoted to a generalization of the experimental results and a theoretical description of the transfer of molecular chirality to orientationally ordered systems with the participation of both chiral molecular substituents with an asymmetric carbon atom and planar or quasi-planar fragments chirally distorted relative to each other. The stereochemical aspects of induction associated with the structural correspondences of the dopant and nematic liquid crystal, as well as the main classes of optically active additives, are discussed. Application of metal complexes, both Werner and macroheterocyclic, are presented. Special attention is paid to the results of the mechanisms study of chiral transfer due to various intermolecular interactions: hydrogen bonding, axial coordination, and the formation of inclusion compounds. The high efficiency of induction of spiral mesophases has been demonstrated with a combination of different self-assembly mechanisms in liquid crystal - chiral additive systems.

High-Efficiency Visual Terahertz Detector Based on Three-Dimensional Porous Graphene and Cholesteric Liquid Crystal Microcapsule

2020 ◽  
Vol 40 (17) ◽  
pp. 1704002
Author(s):  
肖芮文 Xiao Ruiwen ◽  
肖俊羽 Xiao Junyu ◽  
金萍 Jin Ping ◽  
张荣轩 Zhang Rongxuan ◽  
王磊 Wang Lei
Keyword(s):  
Liquid Crystal ◽  
High Efficiency ◽  
Cholesteric Liquid Crystal ◽  
Three Dimensional ◽  
Terahertz Detector ◽  
Porous Graphene

Numerical Simulation of High Accuracy and High Efficiency Beam Steering Based on Liquid Crystal Optical Phase Array

2014 ◽  
Vol 41 (2) ◽  
pp. 0202002
Author(s):  
师宇斌 Shi Yubin ◽  
马浩统 Ma Haotong ◽  
马阎星 Ma Yanxing ◽  
吕洋 Lü Yang ◽  
司磊 Si Lei
Keyword(s):  
Numerical Simulation ◽  
Liquid Crystal ◽  
High Efficiency ◽  
Beam Steering ◽  
High Accuracy ◽  
Phase Array ◽  
Optical Phase
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