COMMAND SURFACE-INDUCED SWITCHING OF THE OPTICAL-PROPERTIES OF LIQUID-CRYSTALLINE THIN-FILM STRUCTURES

We report on optical waveguide structures with light propagation in a nematic liquid crystalline thin him. The liquid crystal (LC) is sandwi ched between two so-called photochromic command layers, consisting of a polymer with azobenzene side chains. When exposed to light of approp riate wavelength, the azobenzene side chains undergo a trans <----> ci s isomerization process, inducing a homeotropic <----> parallel change in the LC alignment. These orientational changes affect the set of re fractive indices of the LC thin film and, hence, can be detected by op tical waveguide methods. As a possible application of the command surf ace effect in optical waveguide structures, we present an optical swit ching and information storage device.