[OPTICAL REVIEW Vol. 6, No. 6 (1999) 518-521]

Direct Fabrication Methods of Surface Relief Electro-Optic Gratings in Azo-Polymer Films

Katsuhiro MUNAKATA,1 Kenji HARADA,1 Nobukazu YOSHIKAWA,1 Masahide ITOH,1 Shinsuke UMEGAKI2 and Toyohiko YATAGAI1

1Institute of Applied Physics, University of Tsukuba and Tsukuba Advanced Research Alliance, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8573 Japan, 2Faculty of Science and Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku, Yokohama, Kanagawa, 223-0061 Japan

(Received June 30, 1999; Accepted July 30, 1999)

Two fabrication methods of surface relief electro-optic (EO) gratings in azo-polymer films are described: surface deformation by a continuous wave laser and laser ablation by a pulse laser. In the fabrication process, the periodic intensity modulation of laser beams is formed by an interference fringe or a phase mask. The surface relief EO grating is fabricated by poling the surface relief grating (SRG) after the SRG fabrication process. The linear dependence of an applied voltage in the modulation efficiency of the first-order diffraction beam is observed. The proposed methods are effective for highly-efficient surface relief EO grating fabrication.

Key words : electro-optic grating, surface relief grating, azo-polymer film, electro-optic effect, laser ablation