Abstract

In degenerate four-wave mixing, the interaction of three input beams with a nonlinear medium generates a fourth coherent signal beam. The coherent nature of the signal beam offers several advantages in minor species detection in hostile or luminous environments. Prior experiments using ultraviolet input beams to detect OH or NH radicals in flames^1,2 and NO as a low pressure gas³ readily demonstrated good background discrimination and high signal collection efficiency.

© 1991 Optical Society of America