[OPTICAL REVIEW Vol. 9, No. 3 (2002) 106-111]

Phase Conjugation in Saturable Absorbing Dye Films by Degenerate Four-Wave Mixing and Holographic Processes Using Nanosecond Pulse and CW Lasers

Hiromasa TANAKA, Akira HORIKOSHI, Hirofumi FUJIWARA* and Kazuo NAKAGAWA

Department of Materials Science and Engineering, Muroran Institute of Technology, 27-1 Mizumoto, Muroran 050-8585, Japan

(Received September 12, 2001; Accepted March 4, 2002)

We report on the simultaneous generation of phase-conjugate signals by degenerate four-wave mixing (DFWM) and holographic processes using a nanosecond pulse and a CW lasers in polyvinyl alcohol (PVA) films doped with four kinds of saturable absorbing dyes. For the pulse laser, of the four kinds of dye-doped PVA films, the erythrosine B-doped PVA and uranine doped-PVA films generate PC signals only by the DFWM process, while the other dye-doped PVA films generate PC signals simultaneously by not only the DFWM process but also the holographic process. Especially, the safranin T-doped PVA film generates strong PC signals by the holographic process. In contrast, all of the dye-doped PVA films generate the two types of PC signals for the CW laser. The fading of dye molecules is found to result in the generation of the holographic component of PC signals which governs the temporal behavior of the total PC signals.

Key words: degenerate four-wave mixing, dye-doped polymer films, saturable absorbing dye, nanosecond phase conjugation, fading of dye molecules