Prof. Hoi Sing Kwok Profile

Prof. Hoi Sing Kwok

Chair Professor at Hong Kong Univ of Science and Technology

SPIE Involvement:

Author

Publications (39)

Proceedings Article | 17 April 2020 Paper

High-efficient liquid crystal polarization gratings for autostereoscopic 3D display

Da Chen, Huijie Zhao, Qi Guo, Dong Xu, Linghao Sun, V. Chigrinov, H. S. Kwok

Proceedings Volume 11455, 1145521 (2020) https://doi.org/10.1117/12.2563404

KEYWORDS: Polarization, 3D displays, Diffraction gratings, Liquid crystals, Diffraction, Prisms, Holography, Digital holography

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Proceedings Article | 6 September 2019 Paper

Polarization-dependent diffractive optical elements based on photoalignment of liquid crystals

Qi Guo, Kexin Yan, Ruotong Wu, Huijie Zhao, V. Chigrinov, H. S. Kwok

Proceedings Volume 11132, 111320X (2019) https://doi.org/10.1117/12.2528298

KEYWORDS: Polarization, Liquid crystals, Absorption, Diffraction, Polymers, Ultraviolet radiation, Molecules, Diffraction gratings, Diffractive optical elements

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Proceedings Article | 30 January 2019 Paper

Flatness and diffractive wavefront measurement of liquid crystal computer-generated hologram based on photoalignment technology

Yao Hu, Shihang Fu, Shaopu Wang, Wanlong Zhang, Hoi Sing Kwok

Proceedings Volume 10841, 108410I (2019) https://doi.org/10.1117/12.2504969

KEYWORDS: Wavefronts, Computer generated holography, Diffraction, Liquid crystals, Manufacturing, Optical testing, Etching, Wavefront sensors

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Proceedings Article | 27 August 2008 Paper

Progress in nano-structured alignment layers for liquid crystal displays

H. Kwok, F. S. Y. Yeung

Proceedings Volume 7050, 70500Q (2008) https://doi.org/10.1117/12.794404

KEYWORDS: Liquid crystals, Optical alignment, LCDs, Molecules, Glasses, Printing, Liquids, Solids, Atomic force microscopy, Temperature metrology

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Proceedings Article | 9 February 2007 Paper

Liquid crystal photoalignment: history and future

V. Chigrinov, H. Kwok, Hirokazu Takada, Haruyoshi Takatsu

Proceedings Volume 6487, 64870F (2007) https://doi.org/10.1117/12.714853

KEYWORDS: Liquid crystals, LCDs, Polarizers, Absorption, Molecules, Polarization, Ultraviolet radiation, Polymers, Wave plates, Liquid crystal on silicon

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In this original review we briefly consider the novel azo-dye photo-aligning technology: history and the perspectives for future applications in liquid crystal (LC) devices. The review describes the following items. The brief introduction to the history of photoalignment and the basic classes of the photoaligning materials: photosensitive polymers, azodyes and monolayers will follow with an introduction to the physical mechanisms of the photo-aligning and photo-patterning technology. The advantages and drawbacks of various photo-aligning materials are analyzed from the point of view of practical applications. The detail description of the diffusion photo-aligning in azo-dye materials is provided. The characteristics of azo-dye photoaligning LC layers are compared with those ones prepared by polyimide rubbing method. The characterization of LC-surface interaction, such as pretilt angle and azimuthal anchoring energy is discussed. The newly developed materials should have a controllable pretilt angle and anchoring energy, thus enabling to develop a new generation of the LC devices: with low voltage, fast response and wide viewing angles. The problem of image sticking can be considerably reduced due to the high anchoring energy of azo-dye materials. Promising results, obtained for voltage holding Ratio (VHR) and residual DC voltage (RDC) in azodye photo-aligning materials are also shown. This implies that the azo-dyes can be applied as aligning layers in active matrix liquid crystal displays (AM-LCDs). The possibility to use the photo-aligning layers for new types of liquid crystal displays such as FLCD, VAN-LCD, &pgr;-BTN LCD, optical rewritable memory, microdisplays, and TN-LCD on plastic substrates is demonstrated. The photoaligning of liquid crystal polymers (LCP) and the new classes of devices based on them (optical retarders and compensators) is discussed. Special types of 3D LC alignment, LC alignment inside thin micro tubes, and grating surface were concerned. New superthin photo-aligned polarizers based on azo-dye layers were demonstrated. The polarizers are based both on photo-aligned lyotropic LC as well as pure azo-dye layers. The polarizers can be patterned and put inside LC display cell to serve as internal polarizers. Both color and neutral internal polarizers can be fabricated with the thickness 0.3-0.7 &mgr;m. The electo-optic response of TN-LCD with internal polarizers is practically the same as in case of usual external polarizers. New applications in transflective and 3D displays are envisaged.

Proceedings Article | 5 December 2006 Paper

Aggregation-induced emission

Yongqiang Dong, Jacky Wing Yip Lam, Anjun Qin, Zhen Li, Jiaxin Sun, Hoi Sing Kwok, Ben Zhong Tang

Proceedings Volume 6333, 63331D (2006) https://doi.org/10.1117/12.679373

KEYWORDS: Molecules, Luminescence, Crystals, Molecular aggregates, Electroluminescence, Light emitting diodes, Lithium, Chlorine, Ultraviolet radiation, Quenching (fluorescence)

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Proceedings Article | 16 February 2004 Paper

Enhanced coupling of light from OLED based on nanoporous substrates

H.S. Kwok, H.J. Peng, Y. L. Ho, X.J. Yu

Proceedings Volume 5214, (2004) https://doi.org/10.1117/12.505155

KEYWORDS: Organic light emitting diodes, Glasses, OLED lighting, Photonic crystals, Aluminum, Control systems, Wave propagation, Waveguide modes, Titanium, Transmittance

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Proceedings Article | 5 January 2004 Paper

Polyacetylene liquid crystals: new mesomorphic materials with high thermal stability and novel light-emitting properties

Ben Tang, Jacky Lam, Lo Lai, Zhiliang Xie, Hoi Kwok

Proceedings Volume 5213, (2004) https://doi.org/10.1117/12.504998

KEYWORDS: Polymers, Liquid crystals, Electroluminescence, Liquids, Crystals, Light emitting diodes, Luminescence, Ultraviolet radiation, Nitrogen, Quantum efficiency

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Proceedings Article | 5 January 2004 Paper

New development in photoalignment technologies

Hoi Sing Kwok, Vladimir Chigrinov

Proceedings Volume 5213, (2004) https://doi.org/10.1117/12.509191

KEYWORDS: Liquid crystals, LCDs, Absorption, Ultraviolet radiation, Polymerization, Polarization, Polymers, Electro optics, Lithium, Ferroelectric LCDs

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SPIE Journal Paper | 1 August 2003

Study on optical finite impulse response filter

Ying Zhou, Guangjie Zeng, Feihong Yu, Hoi Sing Kwok

OE, Vol. 42, Issue 08, (August 2003) https://doi.org/10.1117/12.10.1117/1.1586289

KEYWORDS: Finite impulse response filters, Optical filters, Wave plates, Filtering (signal processing), Crystals, Tunable filters, Fourier transforms, Optical engineering, Image filtering, Electronic filtering

Proceedings Article | 12 December 2002 Paper

Mechanism of LCD photoalignment

Hoi-Sing Kwok, M. Khazimullin, Vladimir Chigrinov

Proceedings Volume 4799, (2002) https://doi.org/10.1117/12.453296

KEYWORDS: Molecules, Diffusion, Birefringence, Absorption, Polarization, Oscillators, Solids, LCDs, Phase measurement, Liquid crystals

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Proceedings Article | 20 September 2002 Paper

Design of polarization interference filter used for LCOS projection display

Yinbo He, Jinyi Xiong, Guozhong Wu, Zhaofeng Cen, Feihong Yu, HoiSing Kwok

Proceedings Volume 4919, (2002) https://doi.org/10.1117/12.470955

KEYWORDS: Wave plates, Liquid crystal on silicon, Polarization, Interference filters, Genetic algorithms, Optical filters, Projection systems, Polarizers, LCDs, Optical networks

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Proceedings Article | 16 September 2002 Paper

New analytical method for design of PIF used in color separation/combination optical engine for LCOS display

Jinyi Xiong, Ying Zhou, Guozhong Wu, Zhaofeng Cen, Feihong Yu, HoiSing Kwok

Proceedings Volume 4929, (2002) https://doi.org/10.1117/12.483199

KEYWORDS: Crystals, Testing and analysis, Polarizers, Liquid crystal on silicon, Thin film coatings, Polarization, Interference filters, Optical networks, Thin films, Wave plates

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Proceedings Article | 30 August 2002 Paper

Optical FIR filter based on crystal birefringence: theory and experimental investigation

Ying Zhou, Guozhong Wu, Feihong Yu, HoiSing Kwok

Proceedings Volume 4924, (2002) https://doi.org/10.1117/12.481492

KEYWORDS: Optical filters, Finite impulse response filters, Error analysis, Crystals, Birefringence, Cadmium, Polarizers, Tolerancing, Wave plates, Spectroscopy

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Proceedings Article | 13 June 2002 Paper

Optical funtions of tris (8-hydroxyquinoline) aluminum (Alq3)

Aleksandra Djurisic, Chung Yin Kwong, Weiling Guo, TszWai Lau, Zheng Liu, HoiSing Kwok, Lillian Lam, Wai Kin Chan

Proceedings Volume 4642, (2002) https://doi.org/10.1117/12.470447

KEYWORDS: Atmospheric optics, Absorption, Spectroscopic ellipsometry, Luminescence, Refractive index, Optical properties, Oscillators, Organic light emitting diodes, Laminated object manufacturing, Aluminum

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Proceedings Article | 11 December 2001 Paper

New photo-aligning and photo-patterning technology: superthin internal polarizers, retarders, and aligning layers

Vladimir Chigrinov, HoiSing Kwok, Wing Yip, Vladimir Kozenkov, Elena Prudnikova, Ben Tang, Fouad Salhi

Proceedings Volume 4463, (2001) https://doi.org/10.1117/12.449941

KEYWORDS: Liquid crystals, Polarizers, LCDs, Molecules, Crystals, Absorption, Liquids, Wave plates, Ultraviolet radiation, Polarization

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Proceedings Article | 11 December 2001 Paper

Liquid crystalline light-emitting thermally stable readily processable substituted polyacetylenes

Ben Tang, Jacky Lam, Jingdong Luo, Yuping Dong, Kevin Cheuk, Zhiliang Xie, HoiSing Kwok

Proceedings Volume 4463, (2001) https://doi.org/10.1117/12.449942

KEYWORDS: Polymers, Liquid crystals, Liquids, Crystals, Shape memory alloys, Absorption, Luminescence, Nitrogen, LCDs, Ultraviolet radiation

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Proceedings Article | 11 December 2001 Paper

Optical equivalence theorem for liquid crystal layers: principles and applications

HoiSing Kwok, S. Tang

Proceedings Volume 4463, (2001) https://doi.org/10.1117/12.449939

KEYWORDS: Liquid crystals, Polarization, Wave plates, LCDs, Crystal optics, Reflectivity, Polarizers, Electronics engineering, Systems modeling, Silicon

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Proceedings Article | 19 October 2001 Paper

Optical properties of 3,4,9,10-perylenetetracarboxylic dianhidride (PTCDA)

Chung Yin Kwong, Aleksandra Djurisic, Weiling Guo, E. Herbert Li, Zheng Liu, HoiSing Kwok

Proceedings Volume 4580, (2001) https://doi.org/10.1117/12.444980

KEYWORDS: Surface roughness, Spectroscopic ellipsometry, Data modeling, Optical properties, Atomic force microscopy, Dielectrics, Solids, Thin films, Crystals, Refraction

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Proceedings Article | 24 October 2000 Paper

Liquid crystalline polyacetylenes with tunable luminescent properties

Ben Tang, Jacky Lam, Xiangxing Kong, Fouad Salhi, Kevin Cheuk, HoiSing Kwok, Yuanming Huang, Weikun Ge

Proceedings Volume 4107, (2000) https://doi.org/10.1117/12.405325

KEYWORDS: Polymers, Liquid crystals, Liquids, Crystals, Luminescence, Chromophores, Crystallography, Quenching (fluorescence), Chemistry, LCDs

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Proceedings Article | 24 October 2000 Paper

Bistable twisted nematic liquid crystal display based on a triode electrode structure

Jian-Xin Guo, Zhi-Guo Meng, Man Wong, HoiSing Kwok

Proceedings Volume 4107, (2000) https://doi.org/10.1117/12.405327

KEYWORDS: LCDs, Electrodes, Switching, Liquid crystals, Bistability, Molecules, Glasses, Optical properties, Polarizers, Transmittance

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Proceedings Article | 30 June 2000 Paper

High-contrast SXGA silicon light valves for high-definition video projectors

Ho-Chi Huang, Po-Wing Cheng, HoiSing Kwok

Proceedings Volume 4079, (2000) https://doi.org/10.1117/12.389400

KEYWORDS: Silicon, Light valves, Projection systems, Video, Liquid crystals, LCDs, Reflectivity, Metals, Liquid crystal on silicon, Capacitors

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Proceedings Article | 25 April 2000 Paper

Broadband large-acceptance-angle polarizing beam splitters for reflective LCD projectors

Hing Li, Ho-Chi Huang, HoiSing Kwok

Proceedings Volume 3954, (2000) https://doi.org/10.1117/12.383371

KEYWORDS: LCDs, Projection systems, Optical testing, Mineralogy, Reflectivity, Beam splitters, Reflection, Refractive index, Coating, Lithium

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Proceedings Article | 14 October 1999 Paper

Liquid crystalline polyacetylenes: a new class of mesomorphic materials with novel optical and electronic properties

Ben Tang, Wing Lam, Xiangxing Kong, Priscilla Lee, Xinhua Wan, HoiSing Kwok, Yuanming Huang, Weikun Ge, Hongzheng Chen, Ruisong Xu, Mang Wang

Proceedings Volume 3800, (1999) https://doi.org/10.1117/12.365790

KEYWORDS: Polymers, Liquid crystals, Crystals, Liquids, Luminescence, Visible radiation, Doping, Photoresistors, Electro optic polymers, Nonlinear optics

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Proceedings Article | 14 October 1999 Paper

Application of 2x2 and 4x4 matrices to the modeling of all nematic liquid crystal displays

Shu-Tuen Tang, HoiSing Kwok

Proceedings Volume 3800, (1999) https://doi.org/10.1117/12.365792

KEYWORDS: LCDs, Polarization, Switching, Polarizers, Picosecond phenomena, Matrices, Liquid crystals, Reflectivity, Optical components, Transmittance

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Proceedings Article | 20 May 1999 Paper

Improved projection optics for reflective silicon CMOS light valves

Hui-Feng Li, Zengrong Zheng, Peifu Gu, Liu Xu, Dennis Cheng, Jun Chen, Ho-Chi Huang, HoiSing Kwok

Proceedings Volume 3634, (1999) https://doi.org/10.1117/12.349350

KEYWORDS: Reflectivity, Projection systems, LCDs, Prisms, Light valves, Polarization, Silicon, Optical coatings, Optical design, Polarizers

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Proceedings Article | 17 June 1998 Paper

Frame-sequential miniature silicon display using mixed-mode twisted nematic liquid crystal

Ho-Chi Huang, Po-Wing Cheng, HoiSing Kwok

Proceedings Volume 3421, (1998) https://doi.org/10.1117/12.311044

KEYWORDS: Silicon, LCDs, Liquid crystals, Light emitting diodes, Liquid crystal on silicon, LED displays, Light sources, LED lighting, Colorimetry, Crystals

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Proceedings Article | 30 October 1997 Paper

Switching behavior in bistable twisted nematic liquid crystal displays

HoiSing Kwok, Zhiliang Xie, Tie-Zheng Qian, Ping Sheng

Proceedings Volume 3143, (1997) https://doi.org/10.1117/12.279267

KEYWORDS: Switching, Bistability, Liquid crystals, LCDs, Electro optics, Transmittance, Distortion, Solids, Numerical analysis, Linear polarizers

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Proceedings Article | 30 October 1997 Paper

Design and fabrication of reflective nematic displays with only one polarizer

HoiSing Kwok, F. Yu, Shu-Tuen Tang, Jun Chen

Proceedings Volume 3143, (1997) https://doi.org/10.1117/12.279269

KEYWORDS: Reflectivity, LCDs, Polarizers, Liquid crystals, Reflective displays, Birefringence, Reflectors, Space operations, Manufacturing, Optical properties

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Proceedings Article | 30 September 1996 Paper

Gallium nitride films made by liquid target pulsed laser deposition

X. Sun, Rongfu Xiao, HoiSing Kwok

Proceedings Volume 2888, (1996) https://doi.org/10.1117/12.253102

KEYWORDS: Gallium nitride, Zinc oxide, Silica, Liquids, Sapphire, Pulsed laser deposition, X-ray diffraction, Gallium, Crystals, Spectroscopy

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Proceedings Article | 30 September 1996 Paper

Liquid target pulsed laser deposition and its applications to growing diamond/diamondlike carbon and gallium nitride thin films

Rongfu Xiao, Z. Li, X. Sun, HoiSing Kwok

Proceedings Volume 2888, (1996) https://doi.org/10.1117/12.253113

KEYWORDS: Gallium nitride, Diamond, Liquids, Crystals, Gallium, Carbon, Thin films, Solids, Pulsed laser deposition, Raman spectroscopy

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Proceedings Article | 30 September 1996 Paper

New extended Jones matrix method for twisted nematic liquid crystal displays at oblique incidence

Feihong Yu, Jun Chen, Shu-Tuen Tang, HoiSing Kwok

Proceedings Volume 2892, (1996) https://doi.org/10.1117/12.253335

KEYWORDS: LCDs, Liquid crystals, Refraction, Interfaces, Optical properties, Refractive index, Polarizers, Transmittance, Electro optical modeling, Fabry–Perot interferometers

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Proceedings Article | 20 May 1994 Paper

Superconducting YBa2Cu3O7 bolometer on polycrystalline diamond

Laxminarayana Ganapathi, Jim Zheng, Steven Giles, Rama Rao, HoiSing Kwok

Proceedings Volume 2159, (1994) https://doi.org/10.1117/12.176149

KEYWORDS: Diamond, Silicon, Superconductors, Bolometers, Thin films, Crystals, Multilayers, Chemical vapor deposition, Composites, Diffusion

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Proceedings Article | 11 May 1994 Paper

Mechanism of the carrier recombination in semiconductor dots

Jim Zheng, HoiSing Kwok

Proceedings Volume 2139, (1994) https://doi.org/10.1117/12.175720

KEYWORDS: Excitons, Pulsed laser operation, Semiconductors, Semiconductor lasers, Luminescence, Glasses, Chlorine, Picosecond phenomena, Mode locking, Streak cameras

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Proceedings Article | 2 May 1994 Paper

Unity quantum efficiency and nanosecond response time photodetector using porous silicon film

Jim Zheng, Kaili Jiao, Wayne Anderson, HoiSing Kwok

Proceedings Volume 2149, (1994) https://doi.org/10.1117/12.175266

KEYWORDS: Picosecond phenomena, Silicon, Photodiodes, Sensors, Semiconducting wafers, Quantum efficiency, Silicon films, Thin films, Photodetectors, Antireflective coatings

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Proceedings Article | 21 October 1992 Paper

Ultrafast optical response of YBCO superconductors

Lei Shi, G. Huang, Chris Lehane, Jim Zheng, HoiSing Kwok

Proceedings Volume 1677, (1992) https://doi.org/10.1117/12.137673

KEYWORDS: Picosecond phenomena, Superconductors, Bridges, Ultrafast phenomena, Ultrafast measurement systems, Oscilloscopes, Temporal resolution, Pulsed laser operation, Optical lithography, Silicon

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Proceedings Article | 1 March 1991 Paper

Speed of optically-controlled superconducting devices

HoiSing Kwok, Lei Shi, Jim Zheng, S. Dong, Y. Pang, Paras Prasad

Proceedings Volume 1394, (1991) https://doi.org/10.1117/12.25747

KEYWORDS: Superconductors, Picosecond phenomena, Pulsed laser operation, Transistors, Electronics, Oscilloscopes, Integrated optics, Bridges, Quasiparticles, Four wave mixing

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Proceedings Article | 1 March 1991 Paper

Optical characterization of InP epitaxial layers on different substrates

Kaili Jiao, Jim Zheng, HoiSing Kwok, Wayne Anderson

Proceedings Volume 1361, (1991) https://doi.org/10.1117/12.24441

KEYWORDS: Gallium arsenide, Silicon, Optoelectronic devices, Metalorganic chemical vapor deposition, Luminescence, Excitons, Diffusion, Reflectivity, Modulation, Crystals

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Proceedings Article | 1 October 1990 Paper

Y-Ba-Cu-O thin films as high-speed IR detectors

HoiSing Kwok, Jim Zheng, Q. Ying

Proceedings Volume 1292, (1990) https://doi.org/10.1117/12.21037

KEYWORDS: Sensors, Infrared detectors, Picosecond phenomena, Pulsed laser operation, Thin films, Infrared radiation, Carbon dioxide lasers, Superconductors, Signal detection, Infrared sensors

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