Optimizing OF-CEAS for the Detection of stable methane isotopes in the atmosphere

This work presents an approach to detect and measure the specific isotopic ratio of the stable methane isotopes 12CH4 and 13CH4 using a high-finesse cavity within an Optical Feedback CEAS system. The development of this approach is ongoing with the aim of precisely measuring the isotopic ratio under atmospheric conditions in the mid-infrared (MIR) spectral region around 3001.2 cm-1, where the absorp-tion lines of the two stable isotopologues are located and well separated under a pressure of 40 mbar enabling the simultaneous measurement of both within a spectral range of 1 cm-1.