Patent ID: 8284404

Claim:
A trace gas detector comprising: (a) two or more high finesse optical cavities for receiving one or more gaseous samples for detection, (b) a laser, (c) a frequency reference for the laser, (d) an optical subsystem that (d1) splits a laser beam of light emitted by the laser into two or more split laser beam portions, and (d2) directs one of the two or more split laser beam portions through each of the two or more high finesse optical cavities, (e) two or more photodetectors, wherein each of the two or more photodetectors monitors the split laser beam portion directed through one of the two or more high finesse optical cavities by the optical subsystem, (f) a sampling mechanism that obtains one or more gaseous samples for detection and propagates the one or more gaseous samples through the two or more high finesse optical cavities, and (g) a controller that: (g1) controls intensity and frequency content of light emitted by the laser, (g2) receives information from the two or more photodetectors, (g3) determines a relative absorption between the two or more high finesse optical cavities based upon the information received from the two or more photodetectors, and (g4) directs the operation of the sampling mechanism.