Patent ID: 7569823

Claim:
A compact cavity ring down spectroscopy apparatus for detection and measurement of trace species in a sample gas, which comprises: a housing for said apparatus; a tunable low-power solid-state continuous wave near-infrared diode laser within said housing; an acousto-optic modulator in fiber optical communication with said laser for steering a first order diffraction beam of said laser and for interrupting said beam when resonance is achieved; a ring down resonant cavity within the housing for holding a sample gas, said cavity cell receiving said first order diffraction beam of said laser and comprising at least two high-reflectivity mirrors, wherein said mirrors define an intracavity light path and one of said mirrors is a movable tuning mirror; a piezo transducer drive attached to the tuning mirror for modulating cavity length to maintain resonance between the laser frequency and cavity modes; a photo-detector within said housing, for receiving said beam from the cavity and for generating a resonance signal and a voltage decay (ring down) signal, thereby measuring an interaction of said sample with said intracavity beam; and a microprocessor for reducing the periodic noise in the voltage decay signal by recording the cw-CRD voltage decay signals as data and subjecting the data to an algorithm selected from a cluster analysis or an averaging of the interquartile range of the data configured as a desktop apparatus wherein the foot print is between about 6″ to about 12″ wide, by about 5″ to about 8″ deep, by about 5″ to about 8″ tall.