Single-Photon Imaging Using Electron Multiplication in Vacuum

Abstract

Some decades ago single photon detection and imaging used to be the terrain of photocathode based devices only. The most prominent devices of this family are photomultiplier tubes (PMT) and image intensifiers. During the past decades these devices lost ground to advanced solid state devices like APDs, low noise CMOS imagers, and EMCCDs. Can one expect solid state devices to totally replace vacuum based ones like digital photography replaced the film based one? To answer this question, a deeper understanding of technologies as well as the way the key performance parameters are defined and measured is required. This chapter describes the working principles of photocathodes in general, image intensifiers, and PMTs. It also compares performance characteristics of state-of-the-art state solid state detectors with vacuum based devices. This comparison is not always obvious because of the differences in measurements and definitions employed. Therefore, this chapter also offers the key to compare the performance equally.