Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.
U.S. GOVERNMENT RIGHTS
This invention was made with U.S. Government support under grant Nos. DE-FG03-92ER14304 awarded by the Department of Energy, and AF-F49620-97-1-0316 awarded by the Office of Scientific Research of the Air Force. The U.S. Government has certain rights in this invention.