Optical phase conjugation in methylene blue sensitized gelatin film has been obtained with 514.5-nm radiation from an argon-ion laser with power levels as low as 50 mW/cm2 for the pump beam in a degenerate four-wavemixing configuration. The film with a thickness of 110–120 µm prepared from a solution of a 1.8-mmol concentration of methylene blue sensitized gelatin shows a good phase-conjugate reflectivity of 0.5% for this power level at 514.5 nm, which is well away from its absorption peak at ~ 650 nm.
© 1992 Optical Society of America
A. T. Reghunath, C. K. Subramanian, P. S. Narayanan, and M. R. Sajan, "Optical phase conjugation in methylene blue films," Appl. Opt. 31, 4905-4906 (1992)