Laser Backfire

摘要

Standoff detection is an important method to monitor or probe regions that are otherwise inaccessible to direct sampling techniques. Dogariu et al. (p. 442) report the observation of high-gain infrared lasing in air from the focal region of an ultraviolet laser. The backward-directed infrared laser light could then be used as a remote spectroscopic tool that samples the air on its return path back to the sender position. The technique should find a range of applications-from the detection of greenhouse gas emissions and pollution to the detection of potentially hazardous and explosive materials.