Highly sensitive detection method for gaseous pollutants by internal cavity laser spectroscopy (ILS)

摘要

Contaminants in corrosive gases are detected optically at concentrations below 1 part-per-million (ppm) and extending to a level below 1 part-per-billion (ppb) by using intracavity laser spectroscopy (ILS) techniques. A laser, the ILS laser, is employed as a detector. The ILS laser comprises a gain medium contained in a laser cavity. A gas sample containing gaseous contaminant species is contained within a gas sample cell which is placed inside the laser cavity and on one side of the gain medium. Accordingly, the corrosive gas is prevented from reacting with the components of the ILS laser. 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.