Antiresonant hollow-core fiber-assisted mid-IR hydrocarbons gas sensor

In this work, we present simultaneous and sensitive detection of methane and ethane at ~3.34 µm using a 15-meteres long self-fabricated silica ARHCF and Wavelength Modulation Spectroscopy technique. The ARHCF was filled with a mixture of 10 ppmv and 20 ppmv ethane and methane, respectively via air-tight housings placed at both fiber end-facets. The gas molecules were excited using a self-built continuous wave Difference Frequency Generation source which radiation was coupled into the gas-filled ARHCF. The ARHCF-aided gas sensor reached a minimum detection limit at parts-per-billion by volume level, confirming the suitability of the proposed approach for trace-gas sensing.