Abstract

Single Photon Avalanche Diodes (SPADs) are avalanche photodiodes specifically designed for reverse bias operation above the breakdown voltage (Geiger-mode operation), and used for detecting single optical photons. Studies were performed to relate the attainable timing resolution to the device geometry and operating conditions. A new silicon device structure was designed in order to obtain improved timing performance with respect to previous SPADs.

Extensive tests were carried out in order to ascertain the timing resolution of the device in time-correlated photon counting. The SPAD timing resolution, in terms of its full-width at half­maximum (FWHM) contribution to the overall instrumental response width, is 20 ps with the detector cooled to -65 C, and 28 ps at room temperature. This is the highest resolution so far reported for solid-state single-photon detectors.

Among vacuum tubes, comparable results are obtained only with special microchannel-plate photomultipliers (MCP-PMT). With the excellent timing resolution of the SPAD and the well-known advantages of Time Correlated Photon Counting systems (high sensitivity, linearity etc.), various applications are foreseen in areas so far dominated by streak cameras.

© 1989 Optical Society of America