Picosecond four-wave mixing in a saturable amplifier polymer dye

Summary form only given. Self-diffraction by four-wave-mixing (FWM) in a nonlinear medium such as liquid crystals and photorefractive materials can contribute to perform energy transfer between the two incident beams. FWM in a saturable gain media has received an intense attention in recent years. Owing to the amplification experienced by all the interaction beams, the high diffraction efficiency is expected. This paper presents the demonstration of transient self-diffraction by pico-second FWM in a saturable amplifier Rhodamine 6G polymer dye. In this work, we extend our previous study of FWM in an inverted polymer dye in the transient regime by using signal and pump lasers with pulse duration of much less than the population relaxation time (several nanoseconds) in the polymer dye. The polymer dye saturable amplifier is shown to be an excellent nonlinear material with high diffraction efficiency and fast response time. It has a potential for applications such as real-time holography, phase conjugation, pulse shaping, and all optical temporal-spatial conversion.