A gas sensing laser transceiver that may be used for sensing gas in explosive environments has a laser light source and electronic analysis equipment within an explosion proof chamber. The explosion proof chamber has an optical coupling allowing a laser output from the laser light source to exit the explosion proof chamber. The laser output travels along a path from the transceiver through a region in which a gas is to be detected and back to a photodetector. The photodetector may be intrinsically safe. A light concentrating optic located outside the explosion proof chamber, for example in a separate intrinsically safe chamber, may collect the incoming light and direct it to the photodetector.