Photon detection system and method of photon detection for determining the number of photons received at a photon detector
AssigneeKabushiki Kaisha Toshiba
InventorsBeata Ewa Kardynal, Zhiliang Yuan, Andrew James Shields
Life of this patent
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Abstract
According to one embodiment, a photon detection system determines the number of detected photons. The detection system includes an avalanche photodiode and a measuring unit. The measuring unit measures an avalanche signal induced by illumination before the avalanche current through the device has saturated.
Claims18
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.
A circuit for determining a number of photons in excess of a single photon in a single light pulse detected by an avalanche photodiode, the circuit comprising 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.
A method for determining a number of photons in excess of a single photon in a single light pulse detected by an avalanche photodiode comprising measuring an avalanche signal induced by illumination by the single light pulse in the avalanche photodiode 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;
- applying a bias above 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 measuring the size of the avalanche signal.
Dependencies are inferred from the claim text.