New high-gain detectors for active imaging

New applications require high sensitivity infrared (IR) sensors in order to detect very low incident fluxes. Laser gated imaging has, in particular, additional specific needs. IR sensors for this type of application are synchronized with eye-safe lasers, and have to detect a weak signal backscattered from the target on the order of 10 photons per pulse. They also have to be able to operate with a very short integration time, typically one hundred nanoseconds, to gate the backscattered signal around the target. In partnership with Sofradir, CEA/LETI (France) has developed high quality HgCdTe avalanche photodiodes satisfying these requirements. In parallel, specific studies have been carried out at the Read-Out Circuit level to develop optimized architectures. Thanks to these advances, a new Integrated Dewar Detector Cooler Assembly has been developed. This new product is the first step in a road-map to address low flux infrared sensors in the next few years.