[OPTICAL REVIEW Vol. 9, No. 5 (2002) 222-226]
Characterization of Index and Surface-Relief Gratings Formed in Methacrylate Photopolymers
Takashi KOJIMA and Yasuo TOMITA*
Department of Electronics Engineering, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan
(Received June 14, 2002; Accepted July 4, 2002)
We report on an experimental investigation of the dual (index and surface-relief) grating formation in methacrylate photopolymers in the green. It is found that the dynamics of the diffracted signal from high spatial frequency dual gratings recorded in a thin film sample is mainly determined by the evolution of the volume index grating and is strongly dependent on writing intensities. Low spatial frequency dual gratings recorded in a bulk sample are also investigated. Depth profile and magnitude of the index grating are estimated quantitatively from the diffraction efficiency as a function of polish depth from the bulk sample's surface. It is confirmed that the surface-relief grating is dominant in the light diffraction from the bulk sample.
Key words: photopolymers, holographic recording materials, volume hologram, surface-relief grating, micro-optical elements