INFILTRATED SILICA PHOTONIC CRYSTAL WITH LIQUID CRYSTAL AND VARIOUS ORGANIC LIQUIDS

Tunable photonic crystal has been developed by infiltration of nematic liquid crystal (NLC) and different organic liquids in the void of silica microspheres. Optical properties were investigated by ultraviolet–visible (UV–Vis) spectroscopy. It has been observed that the position of photonic band gap (PBG) shifts from 336[Formula: see text]nm to 326[Formula: see text]nm with the increase of applied field from 0[Formula: see text]V to 9[Formula: see text]V and 316[Formula: see text]nm to 324[Formula: see text]nm after the infiltration of the organic liquids. The refractive index of infiltrated liquid crystal (LC) is calculated at different applied electric field. The present results could be suited for implementation of low cost and compact design tunable devices with low power consumption for high density integrated optics.

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ACTIVE PHOTONIC CRYSTAL NANO-ARCHITECTURES

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863503001663 ◽

2003 ◽

Vol 12 (04) ◽

pp. 587-597 ◽

Cited By ~ 9

Author(s):

CHRISTOPHER J. SUMMERS ◽

CURTIS W. NEFF ◽

WOUNJHANG PARK

Keyword(s):

Liquid Crystal ◽

Photonic Crystal ◽

Photonic Band Gap ◽

Refractive Index Change ◽

Defect Mode ◽

Slab Waveguides ◽

New Class ◽

Highly Nonlinear ◽

Optical Behavior ◽

Photonic Band

The development of nano-scaled photonic crystal structures has resulted in many new devices exhibiting non-classical optical behavior. Typically, in these structures a photonic band gap and associated defect mode are used to create waveguides, resonators, couplers and filters. In this paper we propose that the functionality of these structures can be significantly enhanced by the infiltration of the photonic crystal with other classes of materials, particularly highly nonlinear liquid crystals and electro-optical materials. The properties of conventional 2D PC slab waveguides were simulated by the finite difference time domain method and shown to exhibit very large refraction and dispersion, and significant tunable effects under bias when infiltrated with liquid crystal. In particular, a new superlattice photonic crystal concept is proposed and shown to exhibit up to ~50° tunability in the angle of refraction when alternate liquid crystal infiltrated pixel rows were modulated from their aligned to unaligned state. This modulation corresponds to index changes from 1.5 to 2.1; it is assumed that a refractive index change of up to approximately Δn=0.6 can be achieved. The superlattice effect was also demonstrated to induce new switching and out-coupling effects that were strongly dependent on the direction of propagation and index modulation. These simulations demonstrate the potential of a new class of optically-active photonic crystal architectures to tune giant refraction and dispersion characteristics and to enable new switching phenomena.

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Shift of the photonic band gap in two photonic crystal/liquid crystal composites

Applied Physics Letters ◽

10.1063/1.1461885 ◽

2002 ◽

Vol 80 (11) ◽

pp. 1885-1887 ◽

Cited By ~ 52

Author(s):

Guido Mertens ◽

Thorsten Röder ◽

Ralf Schweins ◽

Klaus Huber ◽

Heinz-S. Kitzerow

Keyword(s):

Liquid Crystal ◽

Photonic Crystal ◽

Band Gap ◽

Photonic Band Gap ◽

Photonic Band

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TUNABLE 1D PHOTONIC CRYSTAL STRUCTURE BASED ON GROOVED Si INFILTRATED WITH LIQUID CRYSTAL E7

International Journal of Nanoscience ◽

10.1142/s0219581x07004894 ◽

2007 ◽

Vol 06 (05) ◽

pp. 333-337

Author(s):

V. A. TOLMACHEV ◽

E. V. ASTROVA ◽

J. A. PILYUGINA ◽

T. S. PEROVA ◽

R. A. MOORE

Keyword(s):

Liquid Crystal ◽

Photonic Crystal ◽

Photonic Band Gap ◽

Short Wave ◽

Isotropic Phase ◽

Initial Alignment ◽

One Dimensional ◽

Homeotropic Alignment ◽

Photonic Band ◽

Wave Edge

Tuning of a photonic band gap (PBG) in a composite one-dimensional photonic crystal infiltrated with nematic liquid crystal (LC) E7 has been evaluated by simulations. It has been found that a sufficient shift of the short wave edge can be obtained only in structures with a pronounced initial alignment of a LC director in the grooves of a single crystalline Si matrix. The largest effect Δλedge = 0.52 μm is predicted for the reorientation of LC molecules from planar homogeneous alignment along the grooves to homeotropic alignment with respect to the Si walls due to an electro-optical effect. The shift in PBG due to thermal tuning resulting from the transition of LC from mesophase to the isotropic phase (Δλedge = 0.4 μm) is less than that due to electric tuning. Thermo-tuning has been demonstrated experimentally, and PBG shift as high as Δλedge = 0.25 μm has been achieved.

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MODELING OF MULTILAYER ULTRATHIN-FILM PHOTONIC CRYSTALS FOR SELECTIVE FILTERS

Doklady BGUIR ◽

10.35596/1729-7648-2019-125-7-88-94 ◽

2019 ◽

pp. 88-94

Author(s):

L. S. Khoroshko ◽

A. V. Baglov ◽

A. A. Hnitsko

Keyword(s):

Crystal Structure ◽

Refractive Index ◽

Liquid Crystal ◽

Photonic Crystal ◽

Photonic Crystals ◽

Band Gap ◽

Photonic Band Gap ◽

Layer Structure ◽

Half Wave ◽

Photonic Band

The aim of the work was to study the optical properties of the one-dimensional photonic crystals from ultrathin alternating layers of titanium and silicon oxides with different order of alternating layers to form defective half-wave layers in the bulk of the photonic crystal. The layer thicknesses were optimized by the dispersion of the refractive index and it was shown that for the formation of 16-layer photonic crystal structure without a half-wave layer with a photonic band gap in the UV region, it is necessary to use layers of titanium dioxide and silicon oxide with a thickness of 28.3 and 53.2 nm, respectively. The structure of the 26-layer photonic crystal with a thickness of 2130 nm with two non-equidistant half-wave layers forming resonant transmission bands in the photonic band gap with peaks at 550 and 601 nm is proposed. Due to the dispersion of the refractive index, the ratio of the thicknesses of TiO2:SiO2 layers varies from 1:1.88 in the case of a 16-layer structure with a photonic band gap in the UV region to 1:1.5 in the case of a 26-layer structure with a photonic band gap in the visible range . The effect of a photonic crystal structure without half-wave layers on the emission spectrum of a liquid crystal display manufactured using IPS technology has been demonstrated in order to reduce the intensity of the blue component to increase the safety of the user's vision. The using of the photonic crystals with two half-wave defective layers allows to achieve complete separation of the spectrum components, which can be used to modify the spectra of large liquid crystal panels, their manufacture using AMOLED technology is a very difficult technological task even for leaders in this field.

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