摘要:

The propagation of guided electromagnetic waves in liquid crystal slab waveguides is considered. The dielectric properties of the liquid crystal layer which govern wave propagation are determined by the configuration of the nematic director. We examine TE and TM modes of a slab dielectric waveguide consisting of a liquid crystal layer which is both anisotropic and inhomogeneous. The uncoupled wave equations for these modes are derived; the equation describing the TM modes is complex. We show that a real propagation constant β exists for all frequencies above cutoff, and obtain the complex field distribution by solving the wave equation using an effective novel numerical technique.

ISSN:1058-725X    

DOI:10.1080/15421409208048255

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We have measured the optical transmittance of UV-cured epoxy PDLC films at normal incidence as a function of applied voltage for a number of different wavelengths. By controlling the cure rate of each film, we were able to study a range of droplet sizes from approximately 0.5 microns to 2.5 microns. By assuming a simple exponential decay law for the transmitted intensity, we have extracted the wavelength dependence of the effective droplet scattering cross-section. This cross-section depends strongly on both the applied voltage and the droplet size. We compare the results with a model based on the anomalous diffraction description of the scattering and find good quantitative agreement.

ISSN:1058-725X    

DOI:10.1080/15421409208048256

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

We present a new optical method to measure the small tilt angles of quasi-planar anchored nematics. We use an hybrid nematic cell which contains twin domains of different birefringence for non zero tilt. We measure the small rotation of the cell which equalize the twin domains birefringence, at a common border. This rotation is proportional to the tilt. The calibration constant can be calculated from the knowledge of the elastic constants anisotropy and the refractive indices, or independently measured from a known tilted anchoring plate. The method is linear in angle, i.e. sensitive and independent of the sample thickness. Comparative measurements of tilt on PVA and SiO are presented and discussed, using this method and other optical measurements of birefringence.

ISSN:1058-725X    

DOI:10.1080/15421409208048257

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/15421409208048234

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor