Patent ID: 9709491
Date: 2017-07-18
CPC Classifications: G01J,G01N

Claim:
1. A system for measuring trace species in a sample gas, said system comprising: a laser source for emitting continuous wave laser beam; an optical isolator for allowing transmission of the laser beam in one direction; a plurality of input mirrors for directing the laser beam into an optical cavity; a first curved mirror located at a first end and a second curved mirror located at a second end, wherein the first and second curved mirrors face each other along a common optical axis to form the optical cavity; a rod positioned between the first and second curved mirrors, wherein the longitudinal axis of the rod is aligned with the optical axis, wherein the rod comprises a linear slot encompassing the optical cavity, wherein the linear slot extends along a predetermined length on the rod along the longitudinal axis, wherein the linear slot is capable of receiving the sample gas, and wherein the rod comprises a first aperture and a second aperture to allow the laser beam received from the plurality of input mirrors to pass through the rod along the optical axis; a tube concentric with and surrounding the rod, wherein the tube comprises a first linear slot and second linear slot, wherein the first and second linear slot oppose each other to form a pass-through slot; and a photodetector for measuring light transmitted through the optical cavity and producing a corresponding signal.