Remote methane sensing using single-photon PPLN-waveguide upconversion lidar

We report on a sensitive methane gas detection system using waveguide-based single-photon upconversion from 1651 nm to 798 nm wavelength for efficient detection. Single-photon light detection and ranging (LIDAR) techniques offer a route to high-sensitivity direct detection, which is important for environmental monitoring in industrial settings. We report on waveguide fabrication, testing, and overall system development using a fibre-pigtailed waveguide package. We achieve an internal upconversion efficiency of 86%. By combining this system with an active imaging module, we demonstrate methane gas sensing in an outdoor environment. We show this approach is a practical route to enhance the sensitivity of cost-effective environmental monitoring systems.