Development of solid state photon detectors is a mature field of engineering and technology based on well-established grounds of solid state physics, and, in the same time, a frontier area of research and innovations faced with dramatic challenges.
The ultimate challenge for the modern developments is a detection of any optical signal at a quantum level – resolving arrival time and spatial location of individual photons – to realize a formula “every photon counts”. To succeed, the developments are focused on improvements in three directions: threshold sensitivity and photon number resolution, fast timing and time resolution, and fine granularity imaging with fast readout. There are many inherent trade-offs to be resolved in each direction.
Development of Silicon Photomultiplier (SiPM) is considered as one of the most promising innovations toward “near ideal” photon detector. The SiPM concept was originated from basic research of avalanche breakdown processes with negative feedback in heterostructures carried out in the P.N. Lebedev Physical Institute in the 1970s–1980s. SiPMs of various designs have been developed in the 1990s – 2000s in Russia (LPI, INR, JINR, CPTA, MEPhI), and their unique performance in the photon number and time resolution has been demonstrated and recognized. Now SiPMs are widely implemented in nuclear medicine, high energy physics, astrophysics, and Cherenkov light detection.
However, developers of Geiger Mode APD or SPAD arrays based on active quenching also found new opportunities for considerable improvements using modern CMOS technology, namely: reduction of a dead space occupied by electronics (Digital SiPM, Philips), multiplexing readout architecture (TU Delft, EPFL), backside illumination (MISPIA), 3D integration of photosensor and electronic layers (3D SiPM, Sherbrook university) and others.
Detection of Cherenkov light is one of the most challenging applications for photodetectors. Superior photon number resolution starting from single photons, picosecond-scale time resolution, and large-area imaging are typical requirements, and many applications demand all these capabilities.
This report presents overview and analysis of the state-of-art in the modern solid state photon detectors as well as their potential and perspectives to meet the quantum imaging challenge.