Abstract

Difference frequency generation has been used for molecular spectroscopy by Pine¹ using an argon ion laser as the fixed frequency source and a tunable dye laser feeding a lithium niobate crystal. It generated 2.2 to 4.2 μm infrared with a resolution of 15 MHz and was demonstrated by detecting the absorption lines of water vapor, ammonia, methane, and nitrous oxide. The advantages of Pine’s system are that it is cw, and smoothly and continuously tunable. The negative aspects of this system are the need for a power hungry and bulky argon ion laser and a dye laser, which are inconvenient for a portable trace gas species detection system.

© 1993 Optical Society of America