Patent ID: 8772700
Filing Date: 2014-07-08
Classification: G01J,H01L

Abstract:
1. A photon detection system configured to determine a number of detected photons in excess of a single photon in a single light pulse, the detection system comprising an avalanche photodiode and a measuring unit configured to measure an avalanche signal induced by illumination by the single light pulse before an avalanche current through the avalanche photodiode has saturated, the avalanche signal being output from the avalanche photodiode, the avalanche signal being measured for a time less than the time which an avalanche takes to saturate, the number of detected photons in excess of the single photon in the single light pulse being determined based on an amplitude of a peak formed by the avalanche signal; wherein the measuring unit comprises an applying unit configured to apply a bias larger than the breakdown voltage of said photodiode across said photodiode for a time duration, said time duration being shorter than the time required for the avalanche current through the avalanche photodiode to saturate after illumination of the avalanche photodiode and a measuring unit configured to measure the size of the avalanche signal.