Holographic gratings in DR1-doped sol-gel silica and ORMOSILs thin films

Holographic diffraction gratings have been obtained in Disperse Red 1 (DR1) -doped silica and ORganically MOdified SILanes thin films (ORMOSILs), produ ced by tetraethylorthosilicate (TEOS) and 3-(triethoxysilyl)propyl isocyana te (ICPTEOS) as precursors for the sol-gel process. For the DR1 + TEOS film , the grating is associated to an irreversible bleaching of the dye and may be detected by a Raman micro-spectroscopy mapping. For films based on ICPT EOS, a transient phase diffraction grating is created by the photoinduced b irefringence. Two characteristic relaxation times of the birefringence grat ing have been measured. (C) 2001 Elsevier Science B.V. All rights reserved.