Single Photon Detection Using Resonator Absorber

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Solution Overview

Problem

Conventional semiconductor-based single photon detectors face limitations due to electrical avalanche processes, including jitter, dark counts, and slow reset times, which affect detection efficiency and reliability.

Innovation Solution

The use of an optical avalanche process employing a resonator to store probe photons, where a signal photon at a different wavelength is absorbed by an absorber, causing a change in the resonant wavelength and releasing multiple probe photons for detection, thereby improving detection reliability and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical avalanche process is used for single photon detection, then detection capability is achieved, but jitter and dark counts increase

Engineering Contradiction:

Improvedetection capabilityVSAvoidjitter and dark counts

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the electrical avalanche process with an optical avalanche process. Instead of using electrical fields to amplify the signal through carrier multiplication, the invention uses optical fields stored in a resonator to detect the single photon absorption event. This substitution eliminates the harmful effects of electrical avalanche such as jitter and dark counts while maintaining detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a resonator as an intermediary element that stores multiple probe photons. The resonator mediates between the single signal photon absorption event and the detection process by accumulating probe photons that can be released and detected when the signal photon is absorbed, thereby avoiding direct electrical detection and its associated problems.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If semiconductor-based SPD is used, then single photon detection is enabled, but reset time increases to hundreds of nanoseconds

Engineering Contradiction:

Improvedetection functionVSAvoidreset time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the slow electrical reset process of semiconductor detectors with a fast optical process. The resonator can release stored probe photons and reset its state on a timescale determined by the optical cavity lifetime, which can be made much shorter than the hundreds of nanoseconds required for semiconductor reset, enabling higher detection rates.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If electrical readout mechanism is used, then signal detection is achieved, but readout bandwidth is limited

Engineering Contradiction:

Improvesignal detectionVSAvoidreadout bandwidth

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The patent substitutes electrical readout with optical readout. The resonator stores probe photons that can be read out optically, bypassing the bandwidth limitations of electrical readout circuits. Optical detection can achieve much higher bandwidths, enabling faster signal readout while maintaining detection precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces noise, enhances readout bandwidth, and lowers dark counts, enabling high-speed, low-noise detection with improved signal-to-noise ratio and parallel readout capabilities.

Implementation Method 1

a resonator to store a plurality of probe photons at a second wavelength

Methodology Applied

Scientific EffectOptical resonance: Resonance

Implementation Method 2

An absorber is disposed at least partially in the resonator and substantially transparent to the plurality of probe photons to absorb the signal photon

Methodology Applied

Scientific EffectPhoton absorption: Absorption (EM radiation)

Implementation Method 3

Absorption of the signal photon causes a change of a resonant wavelength of the resonator and the change of the resonant wavelength causes release of at least some of the plurality of probe photons from the resonator

Methodology Applied

Scientific EffectResonant wavelength shift: Resonance

Implementation Method 4

a detector, in optical communication with the resonator, to generate an electrical signal in response to detection of the at least some of the plurality of probe photons

Methodology Applied

Scientific EffectPhotoelectric detection: Photoelectric Effect

Data Source

PatentUS10312387B2Single photon detection using a resonator with an absorber

Publication Date: 2019.06.04 MASSACHUSETTS INST OF TECH

AI summary

A single photon detector (SPD) includes a resonator to store probe photons at a probe wavelength and an absorber disposed in the resonator to absorb a signal photon at a signal wavelength. The absorber is also substantially transparent to the probe photons. In the absence of the signal photon, the resonator is on resonance with the probe photons, thereby confining the probe photons within the resonator. Absorption of the signal photon by the absorber disturbs the resonant condition of the resonator, causing the resonator to release multiple probe photons. A photodetector (PD) then detects these multiple probe photons to determine the presence of the signal photon.