We demonstrate the photon-number resolution(PNR)capability of a 1.25 GHz gated InGaAs single-photon avalanche photodiode(APD)that is equipped with a simple,low-distortion ultra-narrowband interference circuit for the ...We demonstrate the photon-number resolution(PNR)capability of a 1.25 GHz gated InGaAs single-photon avalanche photodiode(APD)that is equipped with a simple,low-distortion ultra-narrowband interference circuit for the rejection of its background capacitive response.Through discriminating the avalanche current amplitude,we are able to resolve up to four detected photons in a single detection gate with a detection efficiency as high as 45%.The PNR capability is limited by the avalanche current saturation,and can be increased to five photons at a lower detection efficiency of 34%.The PNR capability,combined with high efficiency and low noise,will find applications in quantum information processing technique based on photonic qubits.展开更多
Superconducting nanowire single-photon detectors(SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of inci...Superconducting nanowire single-photon detectors(SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of incident photons during a detection event. Multi-pixel SNSPDs employing multiple read-out channels can provide photon number resolvability(PNR), but they require increased cooling power and costly multi-channel electronic systems. In this work, a single-flux quantum(SFQ) circuit is employed, and PNR based on multi-pixel SNSPDs is successfully demonstrated. A multi-input magnetically coupled DC/SFQ converter(MMD2 Q) circuit with a mutual inductance M is used to combine and record signals from a multi-pixel SNSPD device. The designed circuit is capable of discriminating the amplitude of the combined signals in accuracy of Φ_(0)/M with Φ_(0) being a single magnetic flux quantum. By employing the MMD2 Q circuit,the discrimination of up to 40 photons can be simulated. A 4-parallel-input MMD2 Q circuit is fabricated, and a PNR of3 is successfully demonstrated for an SNSPD array with one channel reserved for the functional verification. The results confirm that an MMD2 Q circuit is an effective tool for implementing PNR with multi-pixel SNSPDs.展开更多
基金supported by the National Natural Science Foundation of China(62250710162 and 12274406)the National Key Research and Development Program of China(2022YFA1405100).
文摘We demonstrate the photon-number resolution(PNR)capability of a 1.25 GHz gated InGaAs single-photon avalanche photodiode(APD)that is equipped with a simple,low-distortion ultra-narrowband interference circuit for the rejection of its background capacitive response.Through discriminating the avalanche current amplitude,we are able to resolve up to four detected photons in a single detection gate with a detection efficiency as high as 45%.The PNR capability is limited by the avalanche current saturation,and can be increased to five photons at a lower detection efficiency of 34%.The PNR capability,combined with high efficiency and low noise,will find applications in quantum information processing technique based on photonic qubits.
基金supported by the National Key R&D Program of China (Grant No. 2017YFA0304000)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDA18000000)the Science and Technology Commission of Shanghai Municipality, China (Grant No. 18511110200)。
文摘Superconducting nanowire single-photon detectors(SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of incident photons during a detection event. Multi-pixel SNSPDs employing multiple read-out channels can provide photon number resolvability(PNR), but they require increased cooling power and costly multi-channel electronic systems. In this work, a single-flux quantum(SFQ) circuit is employed, and PNR based on multi-pixel SNSPDs is successfully demonstrated. A multi-input magnetically coupled DC/SFQ converter(MMD2 Q) circuit with a mutual inductance M is used to combine and record signals from a multi-pixel SNSPD device. The designed circuit is capable of discriminating the amplitude of the combined signals in accuracy of Φ_(0)/M with Φ_(0) being a single magnetic flux quantum. By employing the MMD2 Q circuit,the discrimination of up to 40 photons can be simulated. A 4-parallel-input MMD2 Q circuit is fabricated, and a PNR of3 is successfully demonstrated for an SNSPD array with one channel reserved for the functional verification. The results confirm that an MMD2 Q circuit is an effective tool for implementing PNR with multi-pixel SNSPDs.
