The remote detection of vehicular exhaust as well as battlefield gases is of interest to the Army. Near real-time remote sensing of atmospheric gases can already be performed by using differential absorption lidar or transmission techniques. A new system called the wedge absorption remote sensor has been developed which improves integrated path detection of atmospheric gases. The wedge absorption remote sensor utilizes an emission spike train of short time duration as is found in the long-pulse output mode of a solid-state laser to define the on- and off-line absorption of an atmospheric gas and, hence, its concentration. The wedge absorption remote sensor has performed well as a remote sensor of methane concentrations with an erbium:ytterbium-aluminum-garnet laser as the source. (Author)
