摘要:

The effect of flow-reorientation coupling on to the relaxation process of refractive index grating in nematic liquid crystals has been theoretically investigated. It is shown that in case of oblique incidence of the two beams onto the homeotropic cell the shear flow induced by the electromagnetic field can enhance the amplitude of the director reorientation to about ten times.

ISSN:1058-725X    

DOI:10.1080/10587259808025072

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The irreversible electro-optical response (memory effect) in suspensions of liquid crystals (LCs) and aerosil was investigated. Thereby the influence of the intermolecular interaction in liquid crystals, of the aerosil concentration and its surface treatment and of electric field parameters on the efficiency of the memory effect was studied. The experimental results are discussed in the frame of a model where the filled nematic LC is considered as a system of aerosil agglomerates in a liquid crystal matrix stabilised by elastic forces.

ISSN:1058-725X    

DOI:10.1080/10587259808025073

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Induction and relaxation of optical anisotropy in azobenzene containing polymer films under the action of polarized UV-light irradiation are investigated by polarization UV and IR spectroscopy methods. The dependence of anisotropy relaxation on the exposure conditions is established. The results are interpreted supposing the partial ordering of main-chains fragments in irradiated films. A theoretical model explaining experimental results is developed.

ISSN:1058-725X    

DOI:10.1080/10587259808025074

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The theoretical study of the possible structures in nematic with spherical particles with normal boundary conditions on its surface is carried out. Criteria for the structural transitions between the hyperbolic hedgehog, disclination loop and weakly deformed structure are determined.

ISSN:1058-725X    

DOI:10.1080/10587259808025075

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Recent experimental and theoretical results on the optical nonlinearity associated with molecular reorientation in dye-doped liquids and liquid crystals are reviewed. The variation of intermolecular forces experienced by a photo-excited dye molecule and the resulting change of molecular-statistical parameters such as rotational friction and orientational energy appear to be at the core of this effect. Photoinduced intramolecular charge transfer could be the cause of such variation. The angular momentum conservation is also discussed.

ISSN:1058-725X    

DOI:10.1080/10587259808025076

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The process of propagation of a polarized light beam through the optical system consisting of nematic liquid crystal layer with irregular thickness and circularly oriented director and a linear polarizer has been considered. It has been shown that every state of light polarization of the incident beam has its own, unique intensity distribution after this optical system. The form of the intensity distribution does not depend on the wavelength of the incident radiation.

ISSN:1058-725X    

DOI:10.1080/10587259808025077

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A device for measuring of the parameters of the state of optical polarization has been proposed and experimentally realized. It has been demonstrated that every state of polarization has unique intensity distribution behind the proposed device. This compensator allows us to measure the required parameters of the polarization state in the real-time regime.

ISSN:1058-725X    

DOI:10.1080/10587259808025078

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Interaction of four light waves in a nematic liquid crystal is studied theoretically. We graphically on the phase plane solve equations describing four wave mixing (FWM) under excitation of the static lattices of the dielectric permeability in the nematic liquid crystal. We show existence of unstable eigenmode in FWM. Effect of optical switching of energy is predicted. Energy exchange among the light waves depends on relative initial phase among the four waves. Experimental conditions, under which the effects that are studied would be observable, are discussed.

ISSN:1058-725X    

DOI:10.1080/10587259808025079

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Propagation effects in liquid crystal-core optical fiber waveguides have been investigated. In theory, propagation properties of the TE01and TM01modes in the waveguide composed of a low-birefringence nematic liquid crystal acting as an optical-fiber core have been analyzed. For smaller diameters of the liquid crystal-core, the TE01mode is guided and TM01is the leaky mode, but for larger diameters differences between both modes decrease. The paper presents initial experimental transmission characteristics of the liquid crystal fiber subjected to the influence of selected external perturbations. The experimental results have been compared with the theory in view of some typical optical fiber parameters suggesting a great potential of the liquid crystal-core fibers for environmental sensing.

ISSN:1058-725X    

DOI:10.1080/10587259808025080

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The new thermo-electro-optical effect consist of visible spectra colours changing under a. d.c. electric field in a time periodical temperature variation around the given temperature value. This effect was remarked using a liquid crystal mixture TBBA-CM. In this paper we explain this effect by multiple layer interference. Analysing the theoretical results we obtained a good agreement with the experimental data.

ISSN:1058-725X    

DOI:10.1080/10587259808025081

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor