Recent advances in infrared imagers: toward thermodynamic and quantum limits of photon sensitivity

Infrared detection and imaging are key enabling technologies for a vast number of applications, ranging from communication, to medicine and astronomy, and have recently attracted interest for their potential application in optical interconnects and quantum computing. Nonetheless, infrared detection still constitutes the performance bottleneck for several of these applications, due to a number of unsolved challenges, such as limited quantum efficiency, yield and scalability of the devices, as well as limited sensitivity and low operating temperatures. The current commercially dominating technologies are based on planar semiconducting PIN or avalanche detectors. However, recent developments in semiconductor technology and nano-scale materials have enabled significant technological advancement, demonstrating the potential for groundbreaking achievements in the field. We review the recent progress in the most prominent novel detection technologies, and evaluate their advantages, limitations, and prospects. We further offer a perspective on the main fundamental limits on the detectors sensitivity, and we discuss the technological challenges that need to be addressed for significative advancement of the field. Finally, we present a set of potential system-wide strategies, including nanoscale and low-dimensional detectors, light coupling enhancement strategies, advanced read-out circuitry, neuromorphic and curved image sensors, aimed at improving the overall imagers performance.