Advanced active imaging with single photon avalanche diodes

Ranging and imaging in low light level conditions are a key application of active imaging systems. Typically, intensified cameras (ICCD, EBCMOS) are used to sense the intensity of reflected laser light pulses used for illumination. Recent developments in single photon avalanche diodes (SPAD) show, that sensors having single photon counting capabilities are about to revolutionize low light level imaging and laser ranging. These sensors have the ability to count detection events caused by single photons with very high timing precision. By application of statistical measurement means, the sensitivity of such devices can be increased far beyond classical sensing devices and the needed photon flux has significant lower intensities. New SPAD devices enable the development of novel sensing methods and technologies, and open laser ranging and imaging to new fields of application. Here, we focus on novel hardware structures which are under development as well as the application of avalanche photo diode detectors for light-in-flight detection and non-line-of-sight imaging.