Spectral modulation of a bistable liquid-crystal photonic structure by the polarization effect

Hsiao, Yu Cheng; Zou, Yi; Timofeev, Ivan V.; Zyryanov, V. Ya.; Lee, Wei

doi:10.1364/ome.3.000821

Cited by 32 publications

(24 citation statements)

References 27 publications

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“…If the selective reflection band is located in the visible range, the CLC will reflect colors, rendering its iridescent look. The pitch length and, in turn, the reflective wavelengths of light can be varied by stimuli such as electric or magnetic field, heat, and even light, facilitating CLC's applications as temperature indicators, biosensors, and general optical devices . Recently, light‐driven Bragg reflections of CLC materials have been extensively explored .…”

Section: Introductionmentioning

confidence: 99%

Red, Green, and Blue Reflections Enabled in an Electrically Tunable Helical Superstructure

Hsiao

Yang

Shen

et al. 2018

Advanced Optical Materials

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reflection of light. The structure of a CLC possesses self-assembled periodicity, with the orientation of the CLC mole cules rotating around a helical axis. Such a configuration can separate light traveling along the helical axis into right-and left-handed circularly polarized components. Circularly polarized light with the same handedness as that of the cholesteric molecule is reflected, whereas the other is transmitted. The selective reflection, also known as the Bragg reflection, is produced in the spectral range in terms of wavelengths λ: Δλ = (n e − n o )P, which is determined by the typically temperature-dependent pitch length P of the CLC helix as well as the birefringence defined as the difference between the extraordinary refractive index n e and the ordinary refractive index n o . The Bragg reflection band is centered at λ 0 = (n e + n o )⋅P/2 for incident light propagating along the cholesteric helix. If the selective reflection band is located in the visible range, the CLC will reflect colors, rendering its iridescent look. The pitch length and, in turn, the reflective wavelengths of light can be varied by stimuli such as electric or magnetic field, heat, [9] and even light, [1,10] facilitating CLC's applications as temperature indicators, [3] biosensors, [11] and general optical devices. [12,13] Recently, light-driven Bragg reflections of CLC materials have been extensively explored. [14,15] Such light-sensitive systems can be achieved by doping photoresponsive chiral or achiral azobenzenes into a CLC host so that the resultant cholesteric phase behavior can be modulated by trans-cis photo isomerization of the azo dopant. Nevertheless, the most desirable and least arduous approach to controlling the reflected light is by applying an electric field to the optical component. Recently, Xiang et al. have shown electrical tuning of selective reflection light from ultraviolet to visible based on an oblique helicoidal cholesteric cell. [16] The dielectric heating effect is the process in which a highfrequency electric field heats a dielectric substance. At high frequencies, this effect is caused by molecular dipole rotation within the dielectric material. Some special liquid crystalline materials such as dual-frequency liquid crystals (DFLCs) exhibit such pronounced effect. As a physical property of DFLCs, a relaxation of the component of dielectric constant parallel to the molecular axis, ε || , takes place at some point (typically of the order of 10 kHz) in the frequency domain, causing ε || to drop and become equal to the component of dielectric constant perpendicular to the molecular axis, ε ⊥ . Consequently, the dielectric anisotropy Δε (ε || − ε ⊥ ) changes its sign from positive to negative beyond the so-called crossover frequency f c . This phenomenon Materials with tunable optical properties in the visible spectrum are intriguingly important in science and technology. Such desired tunability can be conveniently accomplished by controlling optical materials with electric field. Now an organic film...

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Section: Introductionmentioning

confidence: 99%

Red, Green, and Blue Reflections Enabled in an Electrically Tunable Helical Superstructure

Hsiao

Yang

Shen

et al. 2018

Advanced Optical Materials

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“…On the other hand, the molecular configuration of the NLC can be affected by the bounding surfaces of a cell (the anchoring effect), which can be controlled by mechanical or chemical treatments. Therefore, a bistable system, with two (or more) stable states can be obtained without electric field requirement [28,29]. In this case, power is required only to change the state of the cell from one steady state to the other which is a challenging problem.…”

Section: B Temperature Effectmentioning

confidence: 99%

Characterization of one dimensional liquid crystal photonic crystal structure

Mohamed

Hameed

El-Okr

et al. 2016

Optik

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“…Furthermore, the modulation of defect mode lasing [25] and the high speed electrooptic switching [26,27] upon applying a low voltage have been demonstrated by using a 1D PC containing an NLC defect layer. Recently, some interesting concepts have been reported using various LC defects in a 1D PC [29][30][31][32]. In this paper, we investigate polarization characteristics of defect mode peaks in a 1D PC with an NLC defect.…”

Section: Introductionmentioning

confidence: 99%

Electrically Rotatable Polarizer Using One-Dimensional Photonic Crystal with a Nematic Liquid Crystal Defect Layer

Ozaki

Yoshino

2015

Crystals

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Polarization characteristics of defect mode peaks in a one-dimensional (1D) photonic crystal (PC) with a nematic liquid crystal (NLC) defect layer have been investigated. Two different polarized defect modes are observed in a stop band. One group of defect modes is polarized along the long molecular axis of the NLC, whereas another group is polarized along its short axis. Polarizations of the defect modes can be tuned by field-induced in-plane reorientation of the NLC in the defect layer. The polarization properties of the 1D PC with the NLC defect layer is also investigated by the finite difference time domain (FDTD) simulation.

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Spectral modulation of a bistable liquid-crystal photonic structure by the polarization effect

Cited by 32 publications

References 27 publications

Red, Green, and Blue Reflections Enabled in an Electrically Tunable Helical Superstructure

Red, Green, and Blue Reflections Enabled in an Electrically Tunable Helical Superstructure

Characterization of one dimensional liquid crystal photonic crystal structure

Electrically Rotatable Polarizer Using One-Dimensional Photonic Crystal with a Nematic Liquid Crystal Defect Layer

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