Infrared Liquid Crystal Tunable Filters

1997 ◽  
Vol 479 ◽  
Author(s):  
Shin-Tson Wu ◽  
Chiung-Sheng Wu
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Absorption Coefficient ◽  
Response Time ◽  
Layer Thickness ◽  
Absorption Spectra ◽  
Computer Simulations ◽  
Contrast Ratio ◽  
Tunable Filters ◽  
Fabry Perot

AbstractComputer simulations on Fabry-Perot liquid crystal tunable filters are performed in the 3–5 and 8–12 μm bands and some discrete laser lines. Effects of transmittance, contrast ratio and response time on liquid crystal birefringence, layer thickness, absorption coefficient and reflectivity of mirrors are analyzed. Absorption spectra and responsible mechanisms of liquid crystals in the 2.5–20 μm region are studied. The fluorinated tolane and diphenyl-diacetylenes and dialkyl diphenyldiacetylenes are found to possess low absorption in the mid-IR range. Mixtures of these compounds will find useful applications for the proposed IR tunable filters.

The Influence of 4,4’-bis[6-(acryloyloxy)-hexyloxy]biphenyl Contents on the Electro-Optical Properties of Polymer Stabilized Liquid Crystals

2013 ◽  
Vol 634-638 ◽  
pp. 2523-2526
Author(s):  
Hui Chang ◽  
Wen Juan Fan ◽  
Xiao Li Liu ◽  
Hong Ying Huo
Keyword(s):  
Optical Properties ◽  
Liquid Crystals ◽  
Response Time ◽  
Polymer Network ◽  
Contrast Ratio ◽  
Monomer Concentration ◽  
Helical Structure ◽  
Switching Process ◽  
Polymer Stabilized ◽  
Structure Of Liquid

The polymer stabilized liquid crystals (PSLC) films was prepared subsequently based on the mesogenic diacrylate monomer 4,4’-bis[6-(acryloyloxy)-hexyloxy]biphenyl (BAB6). The effects of BAB6 on the morphology of polymer network as well as the electro-optical properties of the PSLC films were investigated. The helical structure of liquid crystals was observed in the morphology of polymer network by SEM. Further, a single switching process was observed at lower monomer concentration in this study compared with the former publication. When BAB6 concentration reached 7 %, the response time and contrast ratio of PSLC film were 7 ms and 16.8, respectively.

Investigation of liquid crystal Fabry–Perot tunable filters: design, fabrication, and polarization independence

2014 ◽  
Vol 53 (29) ◽  
pp. H91 ◽  
Author(s):  
Sivan Isaacs ◽  
Frank Placido ◽  
Ibrahim Abdulhalim
Keyword(s):  
Liquid Crystal ◽  
Tunable Filters ◽  
Fabry Perot

scholarly journals Theoretical approach of a polymer stabilized blue phase beam steering

2017 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Jose Francisco Algorri ◽  
Virginia Urruchi ◽  
Noureddine Bennis ◽  
Jose Manuel Sanchez-Pena
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Response Time ◽  
Deflection Angle ◽  
Beam Steering ◽  
Phase Plate ◽  
First Case ◽  
Phase Liquid ◽  
Blue Phase ◽  
Polymer Stabilized

Nematic liquid crystal (LC)-based beam steering has been reported for wide applications. However, for conventional nematic LC beam steering the thickness is of several microns in order to have a wider deflection angle. The response time is relatively slow and the diffraction efficiency is low. In this work, novel beam steering based on polymer stabilized blue phase liquid crystal (PS-BPLC) has been designed and theoretically analyzed. This special mesophase of the chiral doped nematic LC has several advantageous characteristics, for example no need for alignment layers, microsecond response time and an isotropic voltage-off state. The results reveal control over phase retardation. The direction of the steered beam can be tuned by voltage. Depending on voltage configuration, either diffractive beam steering (0.5deg deviation for 1st order) or a tunable continuous phase (tunable deviation of 0.002deg) can be obtained. In the first case, the deflection angle could be tuned by stacks of samples. The second option has the same phase shift for the TE and TM modes so unpolarized light could be used. Full Text: PDF ReferencesF. Feng, I. White, T. Wilkinson, "Free Space Communications With Beam Steering a Two-Electrode Tapered Laser Diode Using Liquid-Crystal SLM", J. Lightwave Technol. 31, 2001 (2013). CrossRef E. Oton, J. Perez-Fernandez, D. Lopez-Molina, X. Quintana, J.M. Oton, M.A. Geday, "Reliability of Liquid Crystals in Space Photonics", IEEE Photonics Journal 7, 1 (2015). CrossRef J. Stockley, S. Serati, "Multi-access laser terminal using liquid crystal beam steering", IEEE in Aerospace Conference, 1972 (2005). CrossRef D. Zografopoulos and E. Kriezis, "Switchable beam steering with zenithal bistable liquid-crystal blazed gratings", Opt. Lett. 39, 5842 (2014). CrossRef Benedikt Scherger, et al., "Discrete Terahertz Beam Steering with an Electrically Controlled Liquid Crystal Device", J. Infrared. Millim. Terahertz Waves 33, 1117 (2012). CrossRef M.A. Geday, X. Quintana, E. Otón, B. Cerrolaza, D. Lopez, F. Garcia de Quiro, I. Manolis, A. Short, Proc. ICSO, Rhodes, Greece, pp. 1-4 (2010). CrossRef Y. Chen, S.-T. Wu, "The outlook for blue-phase LCDs", Proc. SPIE 9005, Advances in Display Technologies IV, 900508 (2014). CrossRef G.D. Love, A.F. Naumov, "Modal liquid crystal lenses", Liq. Cryst. Today 10, 1 (2000). CrossRef V. Urruchi, J.F. Algorri, J.M. Sánchez-Pena, M.A. Geday, X. Quintana, N. Bennis, "Lenticular Arrays Based on Liquid Crystals", Opto-Electron. Rev. 20, 38 (2012). CrossRef J.F. Algorri, G. Love, and V. Urruchi, "Modal liquid crystal array of optical elements", Opt. Express 21, 24809 (2013). CrossRef J.F. Algorri, V. Urruchi, N. Bennis, J. Sánchez-Pena, "Modal liquid crystal microaxicon array", Opt. Lett. 39, 3476 (2014). CrossRef J.F. Algorri, V. Urruchi, B. Garcia-Camara, J.M. Sánchez-Pena, "Generation of Optical Vortices by an Ideal Liquid Crystal Spiral Phase Plate", IEEE Elect. Dev. Lett. 35, 856 (2014). CrossRef D. Xu, Y. Chen, Y. Liu, S. Wu, "Refraction effect in an in-plane-switching blue phase liquid crystal cell", Opt. Express 21, 24721 (2013). CrossRef Z. Ge, S. Gauza, M. Jiao, H. Xianyu, S.T. Wu, "Electro-optics of polymer-stabilized blue phase liquid crystal displays", Appl. Phys. Lett. 94 101104 (2009). CrossRef J. Yan et al., "Extended Kerr effect of polymer-stabilized blue-phase liquid crystals", Appl. Phys. Lett. 96, 071105 (2010). CrossRef X. Wang, D. Wilson, R. Muller, P. Maker, D. Psaltis, "Liquid-crystal blazed-grating beam deflector, Appl. Opt. 39, 6545 (2000). CrossRef

Reflective Chiral-Homeotropic Liquid Crystal Displays

2011 ◽  
Vol 181-182 ◽  
pp. 281-284
Author(s):  
Zhi Ren ◽  
Song Tao Li ◽  
Xi Pai Liu
Keyword(s):  
Liquid Crystal ◽  
Response Time ◽  
Parameter Space ◽  
Contrast Ratio ◽  
Dynamic Parameter ◽  
Liquid Crystal Displays ◽  
Fast Response ◽  
High Contrast ◽  
Fast Response Time ◽  
Space Method

The performance of a reflective chiral-homeotropic (R-CH) liquid crystal (LC) is simulated by the dynamic parameter space method. The normally black reflective chiral-homeotropic display shows weak color dispersion, high contrast ratio, and fast response time.

The high contrast ratio and fast response time of a liquid crystal display lit by a carbon nanotube field emission backlight unit

2008 ◽  
Vol 19 (23) ◽  
pp. 235306 ◽  
Author(s):  
Young Chul Choi ◽  
Ji Won Lee ◽  
Su Kyung Lee ◽  
Mun Seok Kang ◽  
Chang Soo Lee ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Carbon Nanotube ◽  
Response Time ◽  
Field Emission ◽  
Liquid Crystal Display ◽  
Contrast Ratio ◽  
Fast Response ◽  
High Contrast ◽  
Fast Response Time

Polymer Matrix on Polymer Dispersed Liquid Crystals Electro-Optical Properties

2013 ◽  
Vol 677 ◽  
pp. 183-187
Author(s):  
Huey Ling Chang ◽  
Chih Ming Chen
Keyword(s):  
Optical Properties ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Polymer Matrix ◽  
Contrast Ratio ◽  
Butyl Methacrylate ◽  
Driving Voltage ◽  
Ethyl Methacrylate ◽  
Vis Spectroscopy ◽  
Polymer Dispersed

Polymer dispersed liquid crystal (PDLC) films are fabricated with various compositions of E7 liquid crystal (LC), 2-Hydroxy ethyl methacrylate (HEMA), Methyl methacrylate (MMA), n-butyl methacrylate (nBMA), Ethyl methacrylate (EMA), Tetraethylene glycol diacrylate (TEGDA), and Benzoin. The results show that the refractive index of the PDLC films is insensitive to the monomer side groups. The effects of different monomers addition on the microstructure, the corresponding polymer matrix motion and electro-optical properties of the PDLC samples are examined using Dynamic Mechanical Analyzers (DMA) and UV-Vis spectroscopy, respectively. The experimental results reveal that the addition of HEMA and TEGDA yields a considerable improvement in the electro-optical properties and the contrast ratio. Overall, the results show that a PDLC comprising 40wt% E7 liquid crystals, 50mol% TeGDA and 50mol% HEMA has both a high contrast ratio (12.75:1) and a low driving voltage (16 V), and is therefore a suitable candidate for smart window and a wide variety of intelligent photoelectric applications.

ALL-OPTICAL ASYMMETRIC FABRY-PEROT REFLECTION MODULATORS

1993 ◽  
Vol 02 (03) ◽  
pp. 391-399 ◽  
Author(s):  
T. OHTSUKI ◽  
M.F. KROL ◽  
G. KHITROVA ◽  
R. JIN ◽  
R.K. BONCEK ◽  
...  
Keyword(s):  
Response Time ◽  
Quantum Wells ◽  
Insertion Loss ◽  
Pump Beam ◽  
Carrier Density ◽  
Carrier Lifetime ◽  
Contrast Ratio ◽  
Operating Conditions ◽  
Fabry Perot ◽  
All Optical

Operating conditions of all-optical asymmetric Fabry-Perot modulators are discussed based on the experimental results of two modulators with different nonlinear spacers of GaAlInAs/AlInAs and strained-layer InGaAs/GaAs multi-quantum wells. These modulators operate at wavelengths of 1.3 and 0.92 µm, and offer an on/off contrast ratio of greater than 1000:1. An “on” state with an insertion loss of 2.2 dB existed for pump intensities of 30 kW/cm 2 and 3 kW/cm 2, respectively. The corresponding carrier densities for these pump intensities are approximately the same, at 4×1017 cm –3. The switching pump beam intensity of the modulator and its response time are analyzed in terms of saturation carrier density and carrier lifetime of the nonlinear spacer material. Requirements for the nonlinear spacer material and device parameters are discussed for low power and fast modulators.

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