ULTRA-SENSITIVE DETECTION OF CONTAMINANTS IN GAS VIA INTRACAVITY LASER SPECTROSCOPY (ILS)

摘要

Contaminants in gases such as corrosives are detected optically atconcentrations below 1 part-per-million (ppm) and extending to alevel below 1 part-per-trillion (ppb) by using intracavity laser spectroscopy(ILS) techniques. A laser (500), the ILS laser (500), is employedas a detector (10). The ILS laser (500) comprises a gain medium (507)contained in a laser cavity (5). A gas sample containing gaseouscontaminant species is contained within a gas sample cell (406) which isplaced inside the laser cavity (5) and on one side of the gainmedium (406). In the case where gaseous species are to be detected incorrosive gas, the corrosive gas is prevented from reacting with thecomponents of the ILS laser (500). The output signal from the ILS laser (500)is detected and analyzed to identify the gaseous species (viaits spectral signature). The concentration of the gaseous species can bedetermined from the spectral signature as well.