Fast-gated single-photon detector module for wide dynamic range optical measurements

We present an innovative instrument based on a time-gated silicon Single-Photon Avalanche Diode (SPAD) to be used in a Time-Correlated Single-Photon Counting (TCSPC) setup. This instrument is able to increase the dynamic range in optical investigations by means of fast transitions between the OFF and the ON state of the detector. Indeed, an ultra-fast pulse generator embedded in the module allows to enable and disable the detector in less than 200 ps for very short and well-defined time slots. The present technique can be employed when a large amount of undesired photons precedes or follows the optical signal to be measured, such as in time-resolved optical spectroscopy, optical mammography and optical molecular imaging. Thanks to the fast-gating technique it is possible to drastically extend the dynamic range of single-photon optical measurements with short integration times.