Linear cavity laser system for intracavity laser spectroscopy

摘要

Contaminants are detected optically at concentrations below 100 part-per-million (ppm) and extending to a level approaching 1 part-per-trillion (ppt) by using intracavity laser spectroscopy (ILS) techniques. An optically-pumped solid-state laser (the ILS laser) is employed as a detector. The ILS laser comprises an ion-doped crystal medium contained in a linear laser cavity. A gas sample containing gaseous contaminant species is placed inside the laser cavity and on one side of the ion-doped crystal. The output signal from the ILS laser is detected and analyzed to identify the gaseous species (via its spectral signature). The concentration of the gaseous species can be determined from the spectral signature as well. One preferred embodiment of the present invention employs a linear cavity formed between two mirrors separated from the ion-doped crystal laser medium, wherein both ends of the ion-doped crystal are cut at Brewster's angle.