LC Physics

Session 4A: LC Physics
Tuesday, Feb. 14, 2017  10:40-12:05
Chair: Hui-Yu Chen, National Chung Hsing University, Taiwan
Room: Lecture Hall III
11:05 - 11:20 Paper No.  2017-TUE-S0104-O001
Jun-ichi FUKUDA
Calculation of confocal microscope images of cholesteric blue phases

In this paper, we present our numerical attempts to construct confocal microscope images of cholestetric blue phases from their profiles of the dielectric tensor, deduced from the distribution of the orientational tensor order parameter. Instead of resorting to geometrical optics, we solve the Maxwell equations for electromagnetic waves to evaluate the reflected light for incident light with given wavevector, and make an appropriate superposition for different wavevectors of incident light. Our calculated confocal microscope images agree qualitatively with experimental ones in that the symmetry of images is consistent with the ordering of bulk BP I. We also show that the images sensitively depend on the wavelength and the polarization of the incident light. We hope that our theoretical work will extend the applicability of confocal microscopy towards submicron scales.

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11:20 - 11:35 Paper No.  2017-TUE-S0104-O002
Sharmistha Ghosh
Electro-optical switching of blue phase III derived from four-ring bent-core liquid crystal exhibiting large Kerr coefficient

A thermodynamically stable blue phase III (BP III) has been achieved in a host system of bent-core (BC) molecules doped with chiral materials. Utmost 15OC of BPIII was obtained in mixed system. The electro-optic (EO) performance is evaluated in in-plane electric field geometry and stable EO response was observed over temperature range >6 OC. Hysteresis free V-T characteristics is obtained along with high Kerr constant. Kerr constant (K≈8×10-10 mV-2) obtained at low temperature region is the largest among bent-core BP systems reported so far. Dielectric spectroscopy is employed to accurately distinguish isotropic to BP transition. This near room temperature bent-shaped nematogen demonstrates excellent switching properties with sharp rise and fall time (<12mS) and thus becomes a potential candidate for high speed EO devices.

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11:35 - 11:50 Paper No.  2017-TUE-S0104-O003
Pavel S. Pankin

We investigate the hybrid Tamm microcavity states, which underlie the recently proposed WOLEDs, organic solar cells of a new design, and enhancement of the nonlinear optical effects. In this work, we theoretically demonstrate the possibility of controlling the hybrid Tamm microcavity states in a photonic crystal with the 5CB NLC defect bounded by a silver film. The position of the resonant wavelengths corresponding to hybrid modes can be controlled by a temperature or electric field applied to the NLC defect.

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11:50 - 12:05 Paper No.  2017-TUE-S0104-O004
Yu-Chou Chuang
Lasing emission from polymer stabilized Blue Phases microdroplets

In this work,We use microfluidic system to prepare BPs microdroplets with the uniform size from few tens to hundreds μm. By employing the polymer-stabilized method ,we extend the temperature range over 50°C and keep the sample in BPs at room temperature without temperature controller. Moreover, We applied spatially resolved micro-photoluminescence spectroscopy(μ-PL) to observe small region of lasing emission and CCD image of polymer stabilized BPs microdroplets. There are two types of lasing emission we obtained, band-edge lasing and whispering gallery modes(WGMs). In band-edge lasing, the wavelength of lasing emission can be change when we focus the pumping region on different lattice plane. WGMs can be observed on the edge of the droplets due to the light waves are guided round by optical total internal reflection.

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