摘要:

On the basis of local stability analysis we have studied how the surface-like elastic terms influence periodic splay-twist Freedericksz transition in a nematic liquid crystal (NLC) sandwiched between two parallel plates. It is assumed that the planar anchoring favored at both walls and magnetic field is normal to the confining surfaces. Assuming stability of the director ground state in the zero field limit, restrictions on elastic constants are obtained. The critical ratio of the twist and splay elastic constants is calculated as a function ofK24. It is found that there is a critical value ofK24, such that the transition is suppressed underK24exceeds this value. Effects of anchoring energy and theK13- term are discussed.

ISSN:1058-725X    

DOI:10.1080/10587259808025082

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Director spatial distribution near a small spherical particle is calculated for the case of weak director anchoring with the particle surface. The differential cross-section of the light scattering by the director inhomogenuity near the particles is calculated in dipole approximation. We use the Percus - Yevick approximation for hard spheres to account for interference effects. It is studied the influence of the external ac electric field on the director profile and magnitude of light scattering cross-section.

ISSN:1058-725X    

DOI:10.1080/10587259808025083

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Optical nonlinearity of liquid crystals (LC) in the isotropic phase can be enhanced by one order of magnitude by dissolving 0.1% of anthraquinone dye in the LC. The enhancement decreases when the LC transforms into the nematic phase. The same guest-host effect also exists in non-LC liquids. It can be explained by a model based on selective excitation of dye molecules and the change of guest-host interaction induced by optical excitations of the dye.

ISSN:1058-725X    

DOI:10.1080/10587259808025084

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A new series of photochromic copolymethacrylates has been synthesized. Some of those form the “isotropic smectic phase” and are therefore promising for optoelectronic and data recording applications. Phase transitions and structure of the copolymers have been measured, optical properties have been studied.

ISSN:1058-725X    

DOI:10.1080/10587259808025085

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Repolarization kink motion in FLC cell is studied. The effects of the anisotropy energy time dependence and cell inhomogeneity are investigated.

ISSN:1058-725X    

DOI:10.1080/10587259808025086

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This contribution aims to give a theoretical state-of-the-art of a new development in the optics of liquid crystals, namely the one with multiply scattered light, initiated by Refs. 1 and 2. The emphasize will be on its unconventional anisotropic features.

ISSN:1058-725X    

DOI:10.1080/10587259808025087

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Experimental results have been given on laser-damage resistance of the liquid crystal modulator with longitudinal operating electrical field. It was shown that laser-damage resistance of the modulator is limited by the ITO transparent electrodes and equals 2.5 − 2.9 J/cm2at 1.06 nm, τ = 15 ns. To improve this parameter we proposed an liquid crystal structure controlled by a transverse electric field in which the ITO electrodes are removed out of the zone intense laser radiation. The main characteristics of this mode liquid crystal modulator are discussed.

ISSN:1058-725X    

DOI:10.1080/10587259808025088

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The analysis of formation of chaotic quantum states for two (or four) orthogonally polarized modes in a tunnelly-coupled optical fiber (TCOF) has been carried out. A special attention is devoted both to the structure of arising polarization instabilities and to the possibility to control of such a quantum state by procedure of quantum nondemolition measurements. New effect of polarization switching is obtained. A new method of generating correlated fluctuations in optical field, based on Raman-Nath diffraction by a fine grating, is discussed. A nonclassical effect is predicted: a suppression of quantum fluctuations below the level of full coherence in the sum of difference photon numbers for the transmitted and scattered waves. The physics of this phenomenon involves a correlation of quantum fluctuations in the intensities of two modes that are coupled nonlinearly. This correlation is most effective in the limit of parametric interaction between the waves in the medium.

ISSN:1058-725X    

DOI:10.1080/10587259808025089

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Three quantities characterising a liquid crystal molecules were voted to study their physical properties. The (α∥-α⊥) of liquid crystals investigated is almost constant at all range of mesophase, but they have a different values for each molecule of liquid crystals. It prove the change of molecule core of liquid crystal influence on their polarizability tensor components. The subject of this work was a three liquid crystal of CB 7, PCH 7 and CCH 7. Molecule core change has clearly influenced on the values of (α∥-α⊥). Components of polarizability tensor of molecule α∥, α⊥were calculated too.

ISSN:1058-725X    

DOI:10.1080/10587259808025090

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We have studied theoretically the reorientation process induced by the electric field inside a bipolar nematic droplet with rigidly fixed poles. Computer simulation has revealed the threshold director reorientation only in that part of a droplet, where the LC director is orthogonal to the applied field, and the nonthreshold reorientation in the rest of the droplet volume. A formula has been proposed to estimate the threshold field. The data obtained have allowed us to calculate a PDLC film transmittance in the framework of the anomalous diffraction approach and to interpret the oscillating behavior of the volt-contrast curve observed experimentally.

ISSN:1058-725X    

DOI:10.1080/10587259808025091

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor