[OPTICAL REVIEW Vol. 8, No. 5 (2001) 364-367]
Time Character of Nanosecond Phase-Conjugate Signals in an Erythrosin B-Doped Polymer Film
Hiromasa TANAKA, Hirofumi FUJIWARA* and Kazuo NAKAGAWA
Department of Materials Science and Engineering, Muroran Institute of Technology, 27-1, Mizumoto, Muroran, 050-8585 Japan
(Received February 17, 2001}; A June 9, 2001)
The generating mechanisms of nanosecond phase-conjugate (PC) signal and the time delay of a backward pump beam, at which the maximum diffraction efficiency of the PC signal can be obtained, are investigated using degenerate four-wave mixing in an erythrosin B-doped polyvinyl alcohol film. The influence of the coherence time of a pulse source on the measurement of the mechanisms of the PC signal generation is also examined. The population gratings due to saturable absorption of dye molecules mainly contribute to the PC signal generation rather than thermal gratings. The maximum diffraction efficiency is obtained at zero time delay of the backward pump beam, at which the coherence peak is observed.
Key words : degenerate four-wave mixing, dye-doped polymer films, saturable absorbing dye, nanosecond phase conjugation, coherence peak