Internally excited acoustic resonator for photoacoustic trace detection


S Danworaphong, IG Calasso, A Beveridge, GJ Diebold, C Gmachl, F Capasso, DL Sivco, and AY Cho. 2003. “Internally excited acoustic resonator for photoacoustic trace detection.” APPLIED OPTICS, 42, 27, Pp. 5561-5565.


The quantum-cascade laser can be used as an infrared source for a small portable photoacoustic trace gas detector. The device that we describe uses a quantum-cascade laser without collimating optics mounted inside an acoustic resonator. The laser is positioned in the center of a longitudinal resonator at a pressure antinode and emits radiation along the length of the resonator exciting an axially symmetric longitudinal acoustic mode of an open-ended cylindrical resonator. Experiments are reported with an 8-mum, quasi-cw-modulated, room-temperature laser used to detect N2O. (C) 2003 Optical Society of America.