Photon-number resolving (PNR) single-photon detectors are of interest for a wide range of applications in the emerging field of photon based quantum technologies. Especially photonic integrated circuits will pave the way for a high complexity and ease of use of quantum photonics. Superconducting nanowire single-photon detectors (SNSPDs) are of special interest since they combine a high detection efficiency and a high timing accuracy with a high count rate and they can be configured as PNR-SNSPDs. Here, we present a PNR-SNSPD with a four photon resolution suitable for waveguide integration. A high statistical accuracy for the photon number is achieved for a Poissonian light source at photon flux below \num{5} photons/pulse with a detection efficiency of 22.7$\pm$3.0 % at 900 nm and pulse rate frequency of 76 MHz. We demonstrate the ability of such a detector to discriminate a sub-Poissonian from a Poissonian light source. This demonstration shows the practical benefit of using a PNR detector in a quantum photonic circuit.
Photon-number resolving (PNR) single-photon detectors are of interest for a wide range of applications in the emerging field of photon based quantum technologies. Especially photonic integrated circuits will pave the way for a high complexity and ease of use of quantum photonics. Superconducting nanowire single-photon detectors (SNSPDs) are of special interest since they combine a high detection efficiency and a high timing accuracy with a high count rate and they can be configured as PNR-SNSPDs. Here, we present a PNR-SNSPD with a four photon resolution suitable for waveguide integration. A high statistical accuracy for the photon number is achieved for a Poissonian light source at photon flux below \num{5} photons/pulse with a detection efficiency of 22.7±3.0 % at 900 nm and pulse rate frequency of 76 MHz. We demonstrate the ability of such a detector to discriminate a sub-Poissonian from a Poissonian light source. This demonstration shows the practical benefit of using a PNR detector in a quantum photonic circuit.
Photon-number resolving (PNR) single-photon detectors are of interest for a wide range of applications in the emerging field of photon-based quantum technologies. Especially photonic integrated circuits will pave the way for a high complexity and ease of use of quantum photonics. Superconducting nanowire singlephoton detectors (SNSPDs) are of special interest since they combine a high detection efficiency and a high timing accuracy with a high count rate and they can be configured as PNR-SNSPDs. Here, we present a PNR-SNSPD with a four photon resolution suitable for waveguide integration operating at a temperature of 4 K. A high statistical accuracy for the photon number is achieved for a Poissonian light source at a photon flux below 5 photons/pulse with a detection efficiency of 22.7 ± 3 % at 900 nm and a pulse rate frequency of 76 MHz. We demonstrate the ability of such a detector to discriminate a sub-Poissonian from a Poissonian light source.
Photon-number-resolving (PNR) single-photon detectors are an enabling technology in many areas, such as photonic quantum computing, nonclassical light-source characterization, and quantum imaging.Here, we demonstrate high-efficiency PNR detectors using a parallel superconducting nanowire singlephoton-detector (P-SNSPD) architecture that does not suffer from crosstalk between the pixels and that is free of latching.The behavior of the detector is modeled and used to predict the possible outcomes given a certain number of incoming photons.We apply our model to a four-pixel P-SNSPD with a system detection efficiency of 92.5%.We also demonstrate how this detector allows reconstructing the photonnumber statistics of a coherent source of light, which paves the way towards the characterization of the photon statistics of other types of light source using a single detector.
Since their first demonstration in 2001 [Gol’tsman et al., Appl. Phys. Lett. 79, 705–707 (2001)], superconducting-nanowire single-photon detectors (SNSPDs) have witnessed two decades of great developments. SNSPDs are the detector of choice in most modern quantum optics experiments and are slowly finding their way into other photon-starved fields of optics. Until now, however, in nearly all experiments, SNSPDs were used as “binary” detectors, meaning that they could only distinguish between 0 and >=1 photons, and photon number information was lost. Recent research has demonstrated proof-of-principle photon-number resolution (PNR) SNSPDs counting 2–5 photons. The photon-number-resolving capability is highly demanded in various quantum-optics experiments, including Hong–Ou–Mandel interference, photonic quantum computing, quantum communication, and non-Gaussian quantum state preparation. In particular, PNR detectors at the wavelength range of 850–950 nm are of great interest due to the availability of high-quality semiconductor quantum dots (QDs) [Heindel et al., Adv. Opt. Photonics 15, 613–738 (2023)] and high-performance cesium-based quantum memories [Ma et al., J. Opt. 19, 043001 (2017)]. In this paper, we demonstrate NbTiN-based SNSPDs with >94% system detection efficiency, sub-11 ps timing jitter for one photon, and sub-7 ps for 2 photons. More importantly, our detectors resolve up to 7 photons using conventional cryogenic electric readout circuitry. Through theoretical analysis, we show that the PNR performance of demonstrated detectors can be further improved by enhancing the signal-to-noise ratio and bandwidth of our readout circuitry. Our results are promising for the future of optical quantum computing and quantum communication.
Since their first demonstration in 2001, superconducting-nanowire single-photon detectors have witnessed two decades of great developments. SNSPDs are the detector of choice in most modern quantum optics experiments and are slowly finding their way into other photon starved fields of optics. Until now, however, in nearly all experiments SNSPDs were used as binary detectors, meaning they can only distinguish between 0 and more than 1 photons and photon number information is lost. Recent research works have demonstrated proof of principle photon number resolving (PNR) SNSPDs counting 2 to 5 photons. The photon-number-resolving capability is highly demanded in various quantum-optics experiments, including HOM interference, photonic quantum computing, quantum communication, and non Gaussian quantum state preparation. In particular, PNR detectors at the wavelength range of 850 to 950 nm are of great interest due to the availability of high quality semiconductor quantum dots and high-performance Cesium-based quantum memories. In this paper, we demonstrate NbTiN based SNSPDs with over 94 percent system detection efficiency, sub 11 ps timing jitter for one photon, and sub 7 ps for two photon. More importantly, our detectors resolve up to 7 photons using conventional cryogenic electric readout circuitry. Through theoretical analysis, we show that the current PNR performance of our detectors can still be further improved by improving the signal to noise ratio and bandwidth of our readout circuitry. Our results are promising for the future of optical quantum computing and quantum communication.
Photon-number-resolving (PNR) detectors are a key enabling technology in photonic quantum information processing. Here, we demonstrate the PNR capacity of conventional superconducting nanowire single-photon detectors by performing ultra-high-resolution time-tagging of the detector-generated electrical pulses. This method provides a viable approach for PNR with high detection efficiency and a high operational repetition rate. We present the implementation of such a PNR detector in the telecom C-band and its characterization by measuring the photon-number statistics of coherent light with tunable intensity. Additionally, we demonstrate the capabilities of the detection method by measuring photon-number correlations of non-classical states.
Superconducting nanowire single-photon detectors (SNSPDs) have abstracted widespread attention in the fields of quantum information and quantum photonics due to their high detection efficiency and low dark count rates (DCR). However, single-pixel SNSPDs exist the notable limitations in detection speed and photon number resolution (PNR) capabilities, which pose challenges for practical applications. In this study, we propose a design of a series four-pixel SNSPD that incorporates a SPICE circuit simulation model to achieve PNR and spatial resolution of the four photons in an ideal state, and then determine the optical cavity structure of the detector at the highest light absorption of up to 97% through optical simulation. This design provides a theoretical foundation for the subsequent fabrication of large-area SNSPD with PNR and spatial resolution, significantly improving the flexibility and adaptability of SNSPDs to meet diverse detection requirements. Furthermore, our work also lays a research foundation for multi-photon detection in quantum communication and quantum computing.