Patent ID: 9212990
Filing Date: 2015-12-15
Classification: G01J,G01N

Abstract:
1. A method of testing for gas-phase analytes, the method comprising: (a) generating a laser beam from a laser gain medium located within an external laser cavity; (b) changing a gain parameter of the laser gain medium so that the laser gain medium emits across a range of wavelengths in response to the change; (c) passing the laser beam through a test sample as the gain parameter is changed, the test sample being located inside the external laser cavity; (d) detecting a change in the spatial or spectral mode distribution or dynamics of the laser emission spectrum by passing the laser beam exiting the external cavity through a Fabry-Perot resonator having a pair of parallel opposed reflectors spaced apart by a fixed distance as the gain parameter is changed; and (e) determining whether the change in the spatial or spectral mode distribution or dynamics of the laser emission spectrum is caused by the test sample; (f) wherein the fixed distance is predetermined by: