AIR SPAD - AlGaAsSb Infrared Single Photon Avalanche Diodes

To address climate change, attention on greenhouse gases has recently expanded from an overwhelming focus on carbon dioxide to include methane. Methane is the second most important greenhouse gas, because for 20 years after release, it is 84 times more potent than carbon dioxide. Methane is a major constituent of natural gas, which has experienced increased demand, owing to a global switch from coal and oil to natural gas. In addition to its detrimental effects on climate change, methane loss caused by leaks is estimated to cost more than 23 billion GBP per year.

Ideally, continuous monitoring for methane with good spatial resolution is needed to identify and minimise methane loss. However, current technologies to detect methane leaks are expensive and time-consuming, resulting in only occasional inspections. Handheld "sniffers" detect leaks at short range, requiring them to be passed over every square foot of a facility. Satellite imaging, (ESA's Copernicus Sentinel 5P satellite) provides wider coverage but suffers from poor spatial resolution (19.5 km2) and intermittent data.

The AIR SPAD project addresses this important shortcoming of current methane detection technology, by developing high-performance single photon detectors, with 4X higher detection efficiency for quantum gas sensing cameras. The project team consists of Phlux, QLM, and The University of Sheffield (TUoS).

QLM has recently demonstrated quantum gas sensing cameras (based on single photon infrared LIDAR) that can image and quantify greenhouse gases at long range. These cameras have great potential to drastically reduce the complexity and cost of gas monitoring of large industrial sites, but their camera performance is currently limited to low frame rates, and static operation caused by inadequate performance of the single photon detectors available.

Phlux Technology Ltd and TUoS have recently demonstrated a new infrared single photon detector technology that has the potential to deliver 4X higher single photon detection efficiency (SPDE) than commercial Single Photon Avalanche Diodes (SPADs). Deployed in QLM's quantum gas sensing, Phlux's AIR SPAD detector could increase the framerate by 4X, while increasing measurement range and methane sensitivity.

We believe this project will not only be a game changer for quantum gas sensing camera capability, but also lead to a UK supplier for SWIR SPADs. AIR SPAD could also be an equally disruptive technology for fibre-based quantum key distribution systems and infrared quantum imaging.