On-Chip Mid-Infrared Gas Detection Using Chalcogenide Glass Waveguide

We demonstrate an on-chip sensor for room-temperature detection of methane gas using a broadband spiral chalcogenide glass waveguide coupled with off-chip laser and detector. The waveguide is fabricated using UV lithography patterning and lift-off after thermal evaporation. We measure the intensity change due to the presence and concentration of methane gas in the mid-infrared (MIR) range. This work provides an approach for broadband planar MIR gas sensing