Patent ID: 9200960
Filing Date: 2015-12-01
Classification: G01J

Abstract:
1. A cavity enhanced absorption spectrometer comprising: a source that generates coherent electro-magnetic radiation having a frequency; an electro-magnetic modulator that creates an electro-magnetic radiation sideband with an adjustable frequency that is offset from the frequency of the coherent electro-magnetic radiation by imparting an adjustable frequency modulation to the coherent electro-magnetic radiation; a RF source that drives the electro-magnetic modulator; a cavity enhanced absorption resonator that receives the electro-magnetic radiation sideband, the cavity enhanced absorption resonator having a resonant frequency; a detector that measures a proximity of the frequency of the electro-magnetic radiation sideband relative to the resonant frequency of the cavity enhanced absorption resonator and generates a proximity detector signal; and a controller that converts the proximity detector signal to a control signal that controls the RF source to drive the electro-magnetic modulator such that the adjustable frequency of the electro-magnetic radiation sideband is adjusted so as to maintain a predetermined proximity to the resonant frequency of the cavity enhanced absorption resonator.