Abstract

In chemical plants and gas pipe lines, continuous monitoring of the leak of inflammable gases, such as H₂, CH₄, and important. Laser spectroscopy provides sensitive detection techniques for various molecules in the atmosphere. Absorption spectroscopy and photo-acoustic spectroscopy (PAS) in the IR region are useful methods for this purpose. However, a tunable IR laser is required and relatively transparent gas in IR, such as hydrogen, is difficult to detect. On the other hand, detection of many kinds of molecules is possible by laser Raman spectroscopy, but the detection sensitivity is low.

© 1996 Optical Society of America