A gas sensor scheme for CO based on optical-feedback linear-cavity enhanced absorption spectroscopy

Trace gases, especially some toxic trace gases, such as carbon monoxide, are of great value for high-precision detection of their concentration in environmental, safety, and health monitoring. To accurately measure CO gas, a novel spectral technique scheme is developed and demonstrated based on cavity-enhanced absorption spectroscopy with a high-quality linear cavity. The scheme can achieve the equal noise absorption sensitivity of 2.37 x 10- 8 cm-1 at the cavity loss of 186 ppm, which can achieve the concentration measurement of 11.7 ppm of CO gas at 1564 nm in the near-infrared band. This approach has the potential for expansion to other gas concentration detection applications and can achieve ppb-ppt level concentration detection.