Two-photon sensitized recording materials for multilayer optical disk

Two types of novel two-photon sensitized recording material writable at 405 nm and 522nm were developed. The fluorescent dye generation type (F-type) material consists of at least two-photon absorption dye (TPAD) and fluorescent dye precursor (FDP), which is non-fluorescent before two-photon recording and fluorescent after two-photon recording due to fluorescent dye generation. The fluorescence quench type (Q-type) material, on the other hand, consists of at least TPAD, fluorescent dye (FD) and fluorescent quencher precursor (QP), which is fluorescent before two-photon recording and the fluorescence intensity is reduced after two-photon recording at the recorded spot due to fluorescent quencher generation. Both types of material showed quadratic dependency of recording light intensity at 522 and 405 nm. A twenty-layer two-photon recording media was fabricated with the Q-type material, and two-photon recording and one-photon fluorescent signal readout was successfully conducted.