scholarly journals High Precision Optical Wavefront Generation Using Liquid Crystal Spatial Light Modulator (LC-SLM)

2021 ◽  
Author(s):  
Zixin Zhao
Keyword(s):  
Liquid Crystal ◽  
Future Development ◽  
Phase Modulation ◽  
Phase Response ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Light Modulator ◽  
Phase Profile ◽  
Modulated Phase ◽  
State Of Art

LC-SLM provides a flexible way to modulate the phase of light with the help of a grayscale pattern loaded on it. Nevertheless, the modulated phase profile is of relatively low accuracy due to the nonlinear and nonuniform response of the liquid crystal layer in the SLM. To improve the performance of LC-SLM on the wavefront generation, the nonlinear and nonuniform phase response needs to be calibrated and compensated effectively. In this chapter, we present some state-of-art methods to measure the phase modulation curve of the LC-SLM. Some methods to measure the static aberration caused by the backplane of the LC-SLM are then presented. Last but not the least, the future development of the LC-SLM in phase modulation is also presented.

scholarly journals Optofluidic Platform Based on Liquid Crystals in X-Cut Lithium Niobate: Thresholdless All-Optical Response

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 908
Author(s):  
Fabrizio Ciciulla ◽  
Annamaria Zaltron ◽  
Riccardo Zamboni ◽  
Cinzia Sada ◽  
Francesco Simoni ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Light Intensity ◽  
Lithium Niobate ◽  
Photovoltaic Effect ◽  
Optical Control ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Threshold Behaviour ◽  
All Optical

In this study, we present a new configuration of the recently reported optofluidic platform exploiting liquid crystals reorientation in lithium niobate channels. In order to avoid the threshold behaviour observed in the optical control of the device, we propose microchannels realized in a x-cut crystal closed by a z-cut crystal on the top. In this way, the light-induced photovoltaic field is not uniform inside the liquid crystal layer and therefore the conditions for a thresholdless reorientation are realized. We performed simulations of the photovoltaic effect based on the well assessed model for Lithium Niobate, showing that not uniform orientation and value of the field should be expected inside the microchannel. In agreement with the re-orientational properties of nematic liquid crystals, experimental data confirm the expected thresholdless behaviour. The observed liquid crystal response exhibits two different regimes and the response time shows an unusual dependence on light intensity, both features indicating the presence of additional photo-induced fields appearing above a light intensity of 107 W/m2.

scholarly journals Phase Compensation of the Non-Uniformity of the Liquid Crystal on Silicon Spatial Light Modulator at Pixel Level

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 967
Author(s):  
Zhen Zeng ◽  
Zexiao Li ◽  
Fengzhou Fang ◽  
Xiaodong Zhang
Keyword(s):  
Liquid Crystal ◽  
Phase Modulation ◽  
Spatial Light Modulator ◽  
Characteristic Curve ◽  
Physical Structure ◽  
Measuring System ◽  
Light Modulator ◽  
Phase Compensation ◽  
Modulation Characteristic ◽  
Liquid Crystal On Silicon

Phase compensation is a critical step for the optical measuring system using spatial light modulator (SLM). The wavefront distortion from SLM is mainly caused by the phase modulation non-linearity and non-uniformity of SLM’s physical structure and environmental conditions. A phase modulation characteristic calibration and compensation method for liquid crystal on silicon spatial light modulator (LCoS-SLM) with a Twyman-Green interferometer is illustrated in this study. A method using two sequences of phase maps is proposed to calibrate the non-uniformity character over the whole aperture of LCoS-SLM at pixel level. A phase compensation matrix is calculated to correct the actual phase modulation of the LCoS-SLM and ensure that the designed wavefront could be achieved. Compared with previously known compensation methods, the proposed method could obtain the phase modulation characteristic curve of each pixel on the LCoS-SLM, rather than a mono look-up table (LUT) curve or multi-LUT curves corresponding to an array of blocks over the whole aperture of the LCoS-SLM. The experiment results show that the phase compensation precision could reach a peak-valley value of 0.061λ in wavefront and this method can be applied in generating freeform wave front for precise optical performance.

scholarly journals Dissipative structures induced by photoisomerization in a dye-doped nematic liquid crystal layer

2018 ◽  
Vol 376 (2135) ◽  
pp. 20170382 ◽  
Author(s):  
I. Andrade-Silva ◽  
U. Bortolozzo ◽  
C. Castillo-Pinto ◽  
M. G. Clerc ◽  
G. González-Cortés ◽  
...  
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Dissipative Structures ◽  
Input Power ◽  
Isotropic Phase ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Nematic Liquid Crystal Layer ◽  
Interface Propagation

Order–disorder phase transitions driven by temperature or light in soft matter materials exhibit complex dissipative structures. Here, we investigate the spatio-temporal phenomena induced by light in a dye-doped nematic liquid crystal layer. Experimentally, for planar anchoring of the nematic layer and high enough input power, photoisomerization processes induce a nematic–isotropic phase transition mediated by interface propagation between the two phases. In the case of a twisted nematic layer and for intermediate input power, the light induces a spatially modulated phase, which exhibits stripe patterns. The pattern originates as an instability mediated by interface propagation between the modulated and the homogeneous nematic states. Theoretically, the phase transition, emergence of stripe patterns and front dynamics are described on the basis of a proposed model for the dopant concentration coupled with the nematic order parameter. Numerical simulations show quite a fair agreement with the experimental observations. This article is part of the theme issue ‘Dissipative structures in matter out of equilibrium: from chemistry, photonics and biology (part 2)’.

Anchoring Induced by Porous Substrate on a Liquid Crystal Layer

1994 ◽  
Vol 239 (1) ◽  
pp. 257-261 ◽  
Author(s):  
Francesco Simoni ◽  
Ferdinando Basile ◽  
Francesco Bloisi ◽  
Luciano Vicari ◽  
Fouad Aliev
Keyword(s):  
Liquid Crystal ◽  
Crystal Layer ◽  
Porous Substrate ◽  
Liquid Crystal Layer

Numerical modelling of twisted nematic devices

1983 ◽  
Vol 309 (1507) ◽  
pp. 203-216 ◽  
Keyword(s):  
Liquid Crystal ◽  
Electric Fields ◽  
Low Cost ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Chiral Nematic ◽  
Twisted Nematic ◽  
Three Dimensional Simulations

Over most of each active region in nematic and chiral nematic twist cells the motion and configuration of the liquid crystal layer does not vary appreciably with position parallel to the surfaces. In such laminar regions the statics, dynamics and optics ot the cell can be accurately simulated at low cost on a computer of moderate size, given the appropriate physical parameters. Methods and recent advances in simulation of laminar regions are reviewed. Bistable twist cells are simulated for illustration. Important problems of stability and edge effects in the presence of electric fields await solution with two- or three-dimensional simulations.

scholarly journals A compact fluorescence polarization analyzer with high-transmittance liquid crystal layer

2018 ◽  
Vol 89 (2) ◽  
pp. 024103 ◽  
Author(s):  
Osamu Wakao ◽  
Ken Satou ◽  
Ayano Nakamura ◽  
Ken Sumiyoshi ◽  
Masanori Shirokawa ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Fluorescence Polarization ◽  
Crystal Layer ◽  
Liquid Crystal Layer ◽  
Polarization Analyzer

Optical Performance of Photonic Crystal Filter with Liquid Crystal Layer

2010 ◽  
Vol 37 (11) ◽  
pp. 2834-2837 ◽  
Author(s):  
宋立涛 Song Litao ◽  
何杰 He Jie ◽  
王华磊 Wang Hualei ◽  
韩毅昂 Han Yiang ◽  
李涛 Li Tao
Keyword(s):  
Liquid Crystal ◽  
Photonic Crystal ◽  
Crystal Layer ◽  
Optical Performance ◽  
Liquid Crystal Layer
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