scholarly journals Two-axis scanning LIDAR using a liquid crystal control

2021 ◽  
Author(s):  
Seiji Nishiwaki
Keyword(s):  
Liquid Crystal ◽  
Laser Light ◽  
Side Surface ◽  
Parallel Beam ◽  
Grating Couplers ◽  
Autonomous Cars ◽  
Scanning Lidar ◽  
Center Axis ◽  
Circular Grating ◽  
Segmented Electrode

Abstract Sophisticated non-mechanical technology for LIDARs is needed to realize safe autonomous cars. We have confirmed the operating principle of a non-mechanical LIDAR by combining concentric circular-grating couplers (CGCs) with a coaxially aligned rod lens. Laser light incident vertically on the center of the inner CGC along the center axis of the lens is radiated from the outer CGC and passes through the side surface of the lens. It is converted to a parallel beam that scans in two axes by applying voltages to two area-segmented electrode layers sandwiching the CGCs and a liquid crystal layer formed on the CGCs. We have demonstrated scanning whose motion ranges were 360 degrees horizontally and 10 degrees vertically. A beam with a spread angle of 0.3 ⨯ 0.8 degrees at a minimum swept vertically up to a frequency of 100 Hz and ten equally spaced beams scanned rotationally with a 6-degree cycle variation of spread of between 0.8 and 3.5 degrees.

scholarly journals Biaxial 360-degree scanning LIDAR using a liquid crystal control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seiji Nishiwaki
Keyword(s):  
Liquid Crystal ◽  
Laser Light ◽  
Side Surface ◽  
Parallel Beam ◽  
Grating Couplers ◽  
Autonomous Cars ◽  
Scanning Lidar ◽  
Center Axis ◽  
Circular Grating ◽  
Segmented Electrode

AbstractSophisticated non-mechanical technology for LIDARs is needed to realize safe autonomous cars. We have confirmed the operating principle of a non-mechanical LIDAR by combining concentric circular-grating couplers (CGCs) with a coaxially aligned rod lens. Laser light incident vertically on the center of the inner CGC along the center axis of the lens is radiated from the outer CGC and passes through the side surface of the lens. It is converted to a parallel beam that scans in two axes by applying voltages to two area-segmented electrode layers sandwiching the CGCs and a liquid crystal layer formed on the CGCs. We have demonstrated scanning whose motion ranges were 360 degrees horizontally and 10° vertically. A beam with a spread angle of 0.3° × 0.8° at a minimum swept vertically up to a frequency of 100 Hz and ten equally spaced beams scanned rotationally with a 6-degree cycle variation of spread of between 0.8° and 3.5°.

Self-pulsing of the laser light transmitted by a nonlinear liquid-crystal interface near the phase transition

1988 ◽  
Vol 13 (10) ◽  
pp. 886 ◽  
Author(s):  
F. Simoni ◽  
G. Cipparrone ◽  
I. C. Khoo ◽  
C. Umeton
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Laser Light ◽  
Crystal Interface

Photo-alignment of liquid crystals in micro capillaries with point-by-point irradiation

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
A. Siarkowska ◽  
M. Jóźwik ◽  
S. Ertman ◽  
T. Woliński ◽  
V. Chigrinov
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Azo Dye ◽  
Laser Light ◽  
Alignment Method ◽  
Uv Laser ◽  
Orientation Control ◽  
Photo Alignment

AbstractA photo-alignment method for micro capillaries based on the SD-1 azo-dye is demonstrated. In this work a liquid-crystal molecules aligning layer is created by point-by-point irradiation of the azo-dye film by using an UV laser light. The method opens up new possibilities for an improved molecules’ orientation control in both glass- and polymer-based photonic liquid crystal fibres.

The impact of NiPc additive and laser light dielectric properties of E63 nematic liquid crystal

2016 ◽  
Vol 505 (1) ◽  
pp. 102-113 ◽  
Author(s):  
Mehmet Kılıç ◽  
Zeynep Güven Özdemir ◽  
Nimet Yilmaz Canli ◽  
Ayşe Evrim Bulgurcuoğlu ◽  
Oğuz Köysal ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Dielectric Properties ◽  
Nematic Liquid Crystal ◽  
Laser Light ◽  
The Impact

scholarly journals Speckle contrast reduction of laser light using a chiral nematic liquid crystal diffuser

2016 ◽  
Vol 109 (26) ◽  
pp. 261104 ◽  
Author(s):  
David J. Hansford ◽  
Julian A. J. Fells ◽  
Steve J. Elston ◽  
Stephen M. Morris
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Laser Light ◽  
Speckle Contrast ◽  
Chiral Nematic ◽  
Contrast Reduction

Synthesis of Small Silicate Spacers for Ferroelectric Liquid Crystal Displays

2010 ◽  
Vol 428-429 ◽  
pp. 383-386
Author(s):  
Bao Gai Zhai ◽  
Yuan Ming Huang
Keyword(s):  
Liquid Crystal ◽  
Laser Light ◽  
Spherical Shape ◽  
Liquid Crystal Displays ◽  
Tetraethyl Orthosilicate ◽  
Laser Light Scattering ◽  
Ferroelectric Liquid Crystal ◽  
Light Scattering Spectroscopy ◽  
Scanning Electron Microcopy ◽  
Scanning Electron

In the presence of the aqueous solution of ammonia, tetraethyl orthosilicate (TEOS) was hydrolyzed in the mixture of ethyl alcohol and water with the results of silica spacers. The spacer morphology and size distribution of the synthesized silica spacers were characterized with scanning electron microcopy and laser light scattering spectroscopy, respectively. Our results demonstrated that the synthesized silica spacers were monodispersed and were in perfect spherical shape with their sizes of about 0.7 m in diameter. The correlation between the spacer sizes and the amount of ammonia catalyst was examined, and the spacer sizes of the silica spacers strongly depended on the temperature of chemical reaction and the amount of catalyst. The diameter of silica spacers could be well controlled by controlling the amount of ammonia catalyst, and uniformly distributed silica spacers were produced. Behavior of the miscibility of the silica spacers with a nematic liquid crystal was examined.

AUTOMATIC LASER LIGHT DETECTION AND FILTERING USING A LIQUID CRYSTAL LYOT FILTER

1993 ◽  
Vol 02 (04) ◽  
pp. 661-676 ◽  
Author(s):  
S. REES ◽  
J. STAROMLYNSKA
Keyword(s):  
Liquid Crystal ◽  
Laser Radiation ◽  
Laboratory Tests ◽  
Laser Light ◽  
Contrast Ratio ◽  
Detection Sensitivity ◽  
Laser Source ◽  
Protection Device ◽  
Cw Laser ◽  
Lyot Filter

A device which acts as both a simple cw laser warner and anti-dazzle protection device has been designed and tested. The design is based on a single stage, double element, tunable liquid crystal Lyot filter. Laboratory tests have shown that the detection sensitivity of the device for monochromatic cw radiation is approximately 43×10−9 W/cm 2 and that the achievable contrast ratio is greater than 100:1 Automatic detection and filtering of a cw laser source has been demonstrated. Results indicate that the algorithm to automatically filter the laser radiation works well and that the extinction obtained is good. Factors which affect the contrast ratio are discussed and improved device design suggested.

Microlens Array Homogenizer for Laser Illuminated Projector

2007 ◽  
Vol 364-366 ◽  
pp. 143-147
Author(s):  
Cheng Huan Chen ◽  
Chien Chuan Chen ◽  
Po Hung Yao
Keyword(s):  
Liquid Crystal ◽  
Laser Beam ◽  
Gaussian Beam ◽  
Uniform Distribution ◽  
Light Source ◽  
Laser Light ◽  
Polarized Light ◽  
Microlens Array ◽  
Diffractive Element ◽  
Laser Light Source

Laser light source is a potential illumination light source for non-emissive display applications, especially for liquid crystal projection displays, due to its requirement of low etendue source and highly polarized light. In order to make a conversion from a circular Gaussian beam profile to a rectangular uniform distribution, a microlens array has been proposed as a homogenizer. The analytical and experimental results show that the microlens array with a pitch of 100um under laser beam illumination works as a diffractive element, and a promising uniformity can be obtained with a stack of two microlens array.

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