Dependence of NO 2 degenerate four-wave-mixing signals on buffer gas pressure

Measurements of degenerate four-wave mixing (DFWM) from NO2 are presented as a function of buffer gas pressure and laser power. The signal strength first decreases and then increases with increasing buffer gas pressure. This dependence on buffer gas pressure is apparently due to the onset of thermal gratings. In the regime where thermal gratings are the dominant source of DFWM signals, the DFWM signal intensity increases as the square of the laser power until saturation.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.