ABSTRACT
This chapter describes the operating principles, construction, and characteristics of major optical detectors. Optical detectors utilizing photoelectric effects can be further divided by their detection principle into two groups: one using external photoelectric effects and the other using internal photoelectric effects. Optical detectors making use of photoelectric effects are widely used as ultraviolet (UV) to infrared (IR) sensors in various applications including measurement instruments, industrial production equipment, and communication devices. Optical detectors also fall under two categories: point detectors that merely detect light intensity and two-dimensional detectors including position sensors and image sensors. In general, optical detectors utilizing the external photoelectric effect are represented by photomultiplier tubes (PMTs) and exhibit fast time response and high sensitivity. Optical detectors using the internal photoelectric effect, such as photodiodes (PDs) and photoconductive cells, offer a wide spectral response range, compact size, and easy operation.
