[OPTICAL REVIEW Vol. 2, No. 3 (1995) 181-186]

Super-Resolution with a Photochromic Mask Layer in an Optical Memory

Tsuyoshi TSUJIOKA,1 Toshio HARADA,1 Minoru KUME,1 Kazuhiko KUROKI1 and Masahiro IRIE2

1New Materials Research Center, SANYO Electric Co., Ltd., 1-1 Dainichi Higashimachi, Moriguchi, Osaka, 570 Japan, 2Institute of Advanced Material Study, Kyushu University 6-1, Kasugakoen, Kasuga, Fukuoka, 816 Japan

(Received February 6, 1995; Accepted March 31, 1995)

The possibility of a super-resolution optical memory using a photochromic mask layer was theoretically discussed. An equation which estimates the transmittance change of the mask layer was derived. The numerical simulation based on the equation showed that the reflectance increase of the layer by photo-irradiation is nonlinear when the optical density of the layer is high. The nonlinear response decreased the crosstalk in adjacent recording tracks and improved the MTF (modulation transfer function) characteristics, resulting in a higher recording density.

Key words : optical memory, photochromism, super-resolution, optical density