Quantitative chemical identification of four gases in remote infrared (9-11 mu m) differential absorption lidar experiments

A combined experimental and computational approach utilizing tunable CO2 lasers and chemometric analysis was employed to detect chemicals and their concentrations in the field under controlled release conditions. We collected absorption spectra for four organic gases in the laboratory by lasing 40 lines of the laser in the 9.3-10.8 mu m range. The ability to predict properly the chemicals and their respective concentrations depends on the nature of the target, the atmospheric conditions, and the round-trip distance. In 39 of the 45 field experiments, the identities of the released chemicals were identified correctly without predictions of false positives or false negatives. (C) 1997 Optical Society of America.