[OPTICAL REVIEW Vol. 5, No. 3 (1998) 158-162]

Spot Shape on Super-Resolution Optical Disks with a Photon-Mode Mask Layer

Tsuyoshi TSUJIOKA1 and Masahiro IRIE2

1New Materials Research Center, SANYO Electric Co., Ltd., Hashiridani 1-18-13, Hirakata, Osaka, 573-8534 Japan 2Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Hakosaki, 6-10-1, Higashi-ku, Fukuoka, 812-8581 Japan

(Received January 19, 1998; Accepted April 13, 1998)

The spot shape on super-resolution optical disks with a photon-mode mask layer was theoretically analyzed. The spot shape was found to depend on the lifetime of the bleached state of the dyes, the light power, and the disk rotation speed. When the lifetime is short, the super-resolution spot shape is not produced at high disk speeds. On the other hand, a dye mask layer with long lifetime, such as a photochromic mask, can produce a sharp spot shape in the higher disk speed region, and therefore is suitable for obtaining a super-resolution disk with a high data transfer rate.

Key words : optical disk, photon-mode, photochromism, high-density recording, super-resolution