ABSTRACT

The state-of-the-art in the photonics area—the avalanche photo detector (APD)—is considered in this entry. The entry begins by describing classic devices and goes on to focus on the actively developed direction solid-state multicell photomultipliers have headed in the last decade. Properties and characteristics of these silicon analogs of the photomultiplier tube, also often called silicon photomultiplier, as well as the prospects for their application, are considered. Two approaches to the development and design of these devices are briefly described: the most common—a “matrix of Geiger APD,” and its alternative—a principle of “discrete amplification.”