Atomic force and optical near-field microscopic investigations of polarization holographic gratings in a liquid crystalline azobenzene side-chain polyester

Abstract

Atomic force and scanning near-field optical microscopic investigations have been carried out on a polarization holographic grating recorded in an azobenzene side-chain liquid crystalline polyester. It has been found that immediately following laser irradiation, a topographic surface grating structure appears. The time development of the grating structure was followed by atomic force microscopy for 20 h by repeatedly scanning the same area of the film. The grating structure disappears after a few hours and a pronounced increase of surface roughness has been found to take place. A near-field optical microscopic scanning of the grating reveals, however, that the bulk of the film remains optically anisotropic.