Patent ID: 8327686
Filing Date: 2012-12-11
Classification: G01N,H01S

Abstract:
1. An apparatus for the photo-acoustic identification and quantification of one or more analyte species comprising: a) a continuous wave laser that emits a laser beam having a single emission line whose emission wavelength can be tuned into coincidence with an absorption line of a gaseous analyte and which is optically matched to a closed path optical cavity having at least a first and a second partially transmissive mirror whereby the laser beam enters the cavity through the first mirror; b) a position actuator mechanically connected to either one of the mirrors whereby a length of the cavity can be changed by applying a voltage to an electrical input of the actuator; c) a laser control unit that modulates the wavelength and/or the output power of the laser responsive to a modulation waveform applied to a modulation input of the laser control unit; d) first and second analog to digital converters that output first and second analog to digital converter signals, respectively; e) a resonant photo-acoustic cell situated inside the cavity whereby an optical intracavity beam traverses a resonance element of the cell with the first analog to digital converter being connected to an output of the resonance element; f) a photo-detector placed into the optical beam emerging from the cavity through the second mirror with the second analog to digital converter being connected to an output of the photo-detector; and g) a data processing and control unit with both the first and second analog to digital converters being connected to inputs of the data processing and control unit and the laser control unit being connected to an output of the data processing and control unit, said data processing and control unit comprising: