OH detection by absorption of frequency-doubled diode laser radiation at 308 nm

Radiation at 308 nm has been obtained by frequency doubling the output of a commercial diode laser cooled to 165 K. A single pass through a crystal of LiIO 3 converted 1 mW of 616 nm radiation to 50 pW of UV, and this was used to detect the OH radical in absorption in a flow tube. Possible extensions of the method for detection of OH in the atmosphere are discussed