scholarly journals Numerical simulation of laser beam interaction with a liquid crystal medium in a miniature fiber-optical system

2017 ◽  
Author(s):  
Roman Galev ◽  
Alexey Kudryavtsev ◽  
Sergey Trashkeev
Keyword(s):  
Numerical Simulation ◽  
Liquid Crystal ◽  
Laser Beam ◽  
Optical System ◽  
Fiber Optical ◽  
Beam Interaction ◽  
Crystal Medium

Novel tunable liquid crystal Fabry-Perot filters for fiber optical system

2001 ◽  
Author(s):  
Hailiang Zhang ◽  
Yan Betremieux ◽  
John Noto ◽  
Robert B. Kerr
Keyword(s):  
Liquid Crystal ◽  
Optical System ◽  
Fabry Perot ◽  
Fiber Optical

scholarly journals Enlarging the Eyebox of Maxwellian Displays with a Customized Liquid Crystal Dammann Grating

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 195
Author(s):  
Ziqian He ◽  
Kun Yin ◽  
Kuan-Hsu Fan-Chiang ◽  
Shin-Tson Wu
Keyword(s):  
Liquid Crystal ◽  
Optical System ◽  
Proof Of Concept ◽  
System Configuration ◽  
Distributed Energy ◽  
Good Efficiency ◽  
High Brightness ◽  
Full Color ◽  
Crystal Polymer ◽  
Maxwellian View

The Maxwellian view offers a promising approach to overcome the vergence-accommodation conflict in near-eye displays, however, its pinhole-like imaging naturally limits the eyebox size. Here, a liquid crystal polymer-based Dammann grating with evenly distributed energy among different diffraction orders is developed to enlarge the eyebox of Maxwellian view displays via pupil replication. In the experiment, a 3-by-3 Dammann grating is designed and fabricated, which exhibits good efficiency and high brightness uniformity. We further construct a proof-of-concept Maxwellian view display breadboard by inserting the Dammann grating into the optical system. The prototype successfully demonstrates the enlarged eyebox and full-color operation. Our work provides a promising route of eyebox expansion in Maxwellian view displays while maintaining full-color operation, simple system configuration, compactness, and lightweight.

Numerical Simulation on Temperature Field in Multi-Layers Inside-Beam Powder Feeding when Laser Cladding

2012 ◽  
Vol 499 ◽  
pp. 114-119 ◽  
Author(s):  
Ming Di Wang ◽  
Shi Hong Shi ◽  
X.B. Liu ◽  
Cheng Fa Song ◽  
Li Ning Sun
Keyword(s):  
Numerical Simulation ◽  
Heat Source ◽  
Laser Beam ◽  
Cooling Rate ◽  
Light Source ◽  
Laser Cladding ◽  
Laser Scanning ◽  
Initial Conditions ◽  
Cladding Layer ◽  
Powder Feeding

Numerical simulation of laser cladding is the main research topics for many universities and academes, but all researchers used the Gaussian laser light source. Due to using inside-beam powder feeding for laser cladding, the laser is dispersed by the cone-shaped mirror, and then be focused by the annular mirror, the laser can be assumed as the light source of uniform intensity.In this paper,the temperature of powder during landing selected as the initial conditions, and adopting the life-and-death unit method, the moving point heat source and the uniform heat source are realized. In the thickness direction, using the small melt layer stacking method, a finite element model has been established, and layer unit is acted layer by layer, then a virtual reality laser cladding manu-facturing process is simulated. Calculated results show that the surface temperature of the cladding layer depends on the laser scanning speed, powder feed rate, defocus distance. As cladding layers increases, due to the heat conduction into the base too late, bath temperature will gradually increase. The highest temperature is not at the laser beam, but at the later point of the laser beam. In the clad-ding process, the temperature cooling rate of the cladding layer in high temperature section is great, and in the low-temperature, cooling rate is relatively small. These conclusions are also similar with the normal laser cladding. Finally, some experiments validate the simulation results. The trends of simulating temperature are fit to the actual temperature, and the temperature gradient can also ex-plain the actual shape of cross-section.

Coupled electric fields in photorefractive driven liquid crystal hybrid cells – theory and numerical simulation

2016 ◽  
Vol 24 (4) ◽  
Author(s):  
P. Moszczyński ◽  
A. Walczak ◽  
P. Marciniak
Keyword(s):  
Numerical Simulation ◽  
Laser Beam ◽  
Electric Fields ◽  
Cell Response ◽  
Liquid Crystalline ◽  
Driving Field ◽  
Self Organized ◽  
Photosensitive Polymer ◽  
Photosensitive Layer ◽  
External Driving

AbstractIn cyclic articles previously published we described and analysed self-organized light fibres inside a liquid crystalline (LC) cell contained photosensitive polymer (PP) layer. Such asymmetric LC cell we call a hybrid LC cell. Light fibre arises along a laser beam path directed in plane of an LC cell. It means that a laser beam is parallel to photosensitive layer. We observed the asymmetric LC cell response on an external driving field polarization. Observation has been done for an AC field first. It is the reason we decided to carry out a detailed research for a DC driving field to obtain an LC cell response step by step. The properly prepared LC cell has been built with an isolating layer and garbage ions deletion. We proved by means of a physical model, as well as a numerical simulation that LC asymmetric response strongly depends on junction barriers between PP and LC layers. New parametric model for a junction barrier on PP/LC boundary has been proposed. Such model is very useful because of lack of proper conductivity and charge carriers of band structure data on LC material.

Laser Beam Modulation Freezing on a Liquid Crystal Surface

1998 ◽  
Vol 320 (1) ◽  
pp. 69-76 ◽  
Author(s):  
D. Andrienko ◽  
O. Francescangeli ◽  
E. Ouskova ◽  
F. Simoni ◽  
S. Slussarenko ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Laser Beam ◽  
Crystal Surface ◽  
Beam Modulation ◽  
Laser Beam Modulation

scholarly journals Nonlinear optics and liquid crystal light valve for laser beam control

2008 ◽  
Vol 139 ◽  
pp. 012010
Author(s):  
Jean Pierre Huignard ◽  
Arnaud Brignon ◽  
Bastien Steinhausser
Keyword(s):  
Liquid Crystal ◽  
Nonlinear Optics ◽  
Laser Beam ◽  
Beam Control ◽  
Light Valve

Study of optical parameters of two fluorinated isothiocyanato nematic liquid crystals exhibiting high birefringence

2014 ◽  
Vol 22 (1) ◽  
Author(s):  
T. Devi ◽  
B. Choudhury ◽  
A. Bhattacharjee ◽  
R. Dabrowski
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Laser Beam ◽  
Order Parameter ◽  
Refractive Indices ◽  
Optical Parameters ◽  
Optical Studies ◽  
High Birefringence ◽  
Two Samples ◽  
Direct Extrapolation

AbstractOptical studies have been carried out on two fluorinated isothiocyanato nematic liquid crystal (LC) compounds 4′-butylcyclohexyl-3, 5-difluoro-4-isothiocyanatobiphenyl and 4′-pentylcyclohexyl-3, 5-difluoro-4-isothiocynatobiphenyl. Transition temperatures of the two samples were confirmed using a polarizing microscope. The two LC compounds were found to exhibit fairly high clearing temperatures. Measurements of refractive indices of the two compounds were done by using thin prism method with He-Ne laser beam of wavelength 630 nm. Birefringence of the two LC compounds was calculated from the measured refractive indices. Both the compounds are found to display fairly high values of birefringence. Validation of a modified four-parameter model, based on Vuks equation describing the temperature dependence of refractive indices of the two liquid crystals, is also presented in this paper. The model is validated by fitting the experimentally measured values of refractive indices, birefringence and average refractive indices of the two nematic LCs with the theoretical values. In this paper, the calculation of order parameters of the LCs is presented by using two methods: direct extrapolation method based solely on the birefringence data and by using modified Vuks method based on Haller’s extrapolation. As observed from the obtained results, this procedure of calculating order parameter gives very reasonable results.

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