High-efficiency and fast-response tunable phase grating using a blue phase liquid crystal

Abstract

We demonstrate a tunable phase grating using a polymer-stabilized blue phase liquid crystal. Because of the electric-field-induced rectangularlike phase profile, a high diffraction efficiency of 40% is achieved. Moreover, this device shows submillisecond response time. The proposed tunable phase grating holds great potential for photonics and display applications.

LCoS SLM Study and Its Application in Wavelength Selective Switch

“…The direction of future research into this kind of LC material would be to lower the operation voltage, reduce hysteresis, and improve properties such as stability and contrast [89,90]. Other approaches for example beam steering with liquid crystal phase grating is also able to achieve faster response (<10 ms) and adjustable switching angles.…”

Switchable Two-Dimensional Liquid Crystal Grating in Blue Phase

“…Based on these properties, the phase grating in BPLC has been investigated in recent years. A polarization dependence of BPLC phase grating has been demonstrated on an IPS electrode [24], which possesses high diffraction efficiency and a fast response time for the transverse-magnetic (TM) polarization of the probe beam.…”

Sub-millisecond nematic liquid crystal switches using patterned command layer

“…These range from changing the LC cell geometry and electrodes design, [2][3][4][5][6][7][8][9][10][11] to changing the LC structure from cholesteric to blue phase (BP). [12][13][14][15][16] Jo et al 8 combined two different LC cell architectures, the vertical alignment (VA) in the initial state and the four-domain twisted nematic (FDTN) with an external field stacking the VA layer onto the planar alignment layer, resulting in a rise time of 13 ms and a driving voltage of 6 V. TaeHoon Yoon et al 9 introduced a three-terminal electrode structure to simultaneously apply an in-plain and a vertical electric field, to show both bright state and grey levels, with the slowest grey-to-grey response of 9.6 ms and from grey to zero in less than 1 ms. Hun Ki Shin and collaborators 10 proposed a polarization switching device using an optically compensated pi cell for polarization-glass-type threedimensional display with a total dynamic response time of 2.5 ms. Won-Kyu Lee and collaborators 11 developed a new LC alignment layer combining single wall carbon nanotubes (SWNT) with a conjugate block copolymer and conventional rubbing, Yielding a high response time (3.8 ms), low operation voltages (1.3 V), and high thermal stability.…”

“…14 All these approaches show clear disadvantages. In fact, to obtain sub-millisecond (ms) performances, high operating voltages (up to 100 V) are used, 12,13,16,17 while in the case of low operating voltages (below 50 V) typical switching times are longer than 10 ms or complex and elaborated architectures and materials need to be used. 9,10,18 Increasing attention has been devoted to micropatterned alignment surfaces, thanks to their flexibility in controlling the main LC alignment properties, such as pretilt angle and anchoring energy, compared to unidirectional alignment methods.…”