Fractal superconducting nanowires detect infrared single photons with 84% system detection efficiency, 1.02 polarization sensitivity, and 20.8 ps timing resolution
Yun Meng, Kai Zou, Nan Hu, Liang Xu, Xiaojian Lan, Stephan Steinhauer, Samuel Gyger, Val Zwiller, Xiaolong Hu
The near-unity system detection efficiency (SDE) and excellent timing resolution of superconducting nanowire single-photon detectors (SNSPDs), combined with their other merits, have enabled many classical and quantum photonic applications. However, the prevalent design based on meandering nanowires makes SDE dependent on the polarization states of the incident photons; for unpolarized light, the major merit of high SDE would get compromised, which could be detrimental for photon-starved applications. Here, we create SNSPDs with an arced fractal geometry that almost completely eliminates this polarization dependence of the SDE, and we experimentally demonstrate 84$\pm$3$\%$ SDE, 1.02$^{+0.06}_{-0.02}$ polarization sensitivity at the wavelength of 1575 nm, and 20.8 ps timing jitter in a 0.1-W closed-cycle Gifford-McMahon cryocooler, at the base temperature of 2.0 K. This demonstration provides a novel, practical device structure of SNSPDs, allowing for operation in the visible, near-, and mid-infrared spectral ranges, and paves the way for polarization-insensitive single-photon detection with high SDE and high timing resolution
In view of promising applications of fractal nanostructures, we analyze the spectra of quantum particles in the Sierpinski carpet and study the non-correlated electron gas in this geometry. We show that the spectrum exhibits scale invariance with almost arbitrary spacing between energy levels, including large energy gaps at high energies. These features disappear in the analogous random fractal---where Anderson localization dominates---and in the regular lattice of equally sized holes---where only two length scales are present. The fractal structure amplifies microscopic effects, resulting in …
Superconducting nanowire single photon detectors are a key technology for quantum information and science due to their high efficiency, low timing jitter, and low dark counts. In this work, we present a detector for single 1550 nm photons with up to 78% detection efficiency, timing jitter below 50 ps FWHM, 158 counts/s dark count rate - as well as a world-leading maximum count rate of 1.5 giga-counts/s at 3 dB compression. The PEACOQ detector (Performance-Enhanced Array for Counting Optical Quanta) comprises a linear array of 32 straight superconducting niobium nitride nanowires which span the…
Superconducting nanowire single-photon detectors are an ideal match for integrated quantum photonic circuits due to their high detection efficiency for telecom wavelength photons. Quantum optical technology also requires single-photon detection with low dark count rate and high timing accuracy. Here we present very low noise superconducting nanowire single-photon detectors based on NbTiN thin films patterned directly on top of Si3N4 waveguides. We systematically investigate a large variety of detector designs and characterize their detection noise performance. Milli-Hz dark count rates are dem…
We demonstrate a large grid of individually addressable superconducting single photon detectors on a single chip. Each detector element is fully integrated into an independent waveguide circuit with custom functionality at telecom wavelengths. High device density is achieved by fabricating the nanowire detectors in traveling wave geometry directly on top of silicon-on-insulator waveguides. Our superconducting single-photon detector matrix includes detector designs optimized for high detection efficiency, low dark count rate and high timing accuracy. As an example, we exploit the high timing re…
Recent progress in the development of superconducting nanowire single-photon detectors (SNSPDs) has delivered excellent performances, and has had a great impact on a range of research fields. The timing jitter, which denotes the temporal resolution of the detection, is a crucial parameter for many applications. Despite extensive work since their apparition, the lowest jitter achievable with SNSPDs is still not clear, and the origin of the intrinsic limits is not fully understood. Understanding its intrinsic behaviour and limits is a mandatory step toward improvements. Here, we report our exper…
Recent progress in the development of superconducting nanowire single-photon detectors (SNSPDs) made of amorphous material has delivered excellent performances, and has had a great impact on a range of research fields. Despite showing the highest system detection efficiency (SDE) ever reported with SNSPDs, amorphous materials typically lead to lower critical currents, which impacts on their jitter performance. Combining a very low jitter and a high SDE remains a challenge. Here, we report on highly efficient superconducting nanowire single-photon detectors based on amorphous MoSi, combining sy…
Time- and number-resolved photon detection is crucial for photonic quantum information processing. Existing photon-number-resolving (PNR) detectors usually have limited timing and dark-count performance or require complex fabrication and operation. Here we demonstrate a PNR detector at telecommunication wavelengths based on a single superconducting nanowire with an integrated impedance-matching taper. The prototyping device was able to resolve up to five absorbed photons and had 16.1 ps timing jitter, <2 c.p.s. device dark count rate, $\sim$86 ns reset time, and 5.6% system detection efficienc…
The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially-separate pixels we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a fa…
Superconducting nanowire avalanche single-photon detectors (SNAPs) with n parallel nanowires are advantageous over single-nanowire detectors because their output signal amplitude scales linearly with n. However, the SNAP architecture has not been viably demonstrated for n > 4. To increase n for larger signal amplification, we designed a multi-stage, successive-avalanche architecture which used nanowires, connected via choke inductors in a binary-tree layout. We demonstrated an avalanche detector with n = 8 parallel nanowires and achieved eight-fold signal amplification, with a timing jitter of…
We demonstrate optical time domain reflectometry over 200 km of optical fiber using low-noise NbTiN superconducting single-photon detectors integrated with Si3N4 waveguides. Our small detector footprint enables high timing resolution of 50ps and a dark count rate of 3 Hz with unshielded fibers, allowing for identification of defects along the fiber over a dynamic range of 37.4 dB. Photons scattered and reflected back from the fiber under test can be detected in free-running mode without showing dead zones or other impairments often encountered in semiconductor photon-counting optical time doma…
We develop single-photon detectors comprising single-mode fiber-coupled superconducting nanowires, with high system detection efficiencies at a wavelength of 940 nm. The detector comprises a 6.5-nm-thick, 110-nm-wide NbN nanowire meander fabricated onto a Si substrate with a distributed Bragg reflector for enhancing the optical absorptance. We demonstrate that, via the design of a low filling factor (1/3) and active area (Φ = 10 μm), the system reaches a detection efficiency of ~60% with a dark count rate of 10 Hz, a recovery time <12 ns, and a timing jitter of ~50 ps.
Dual-Trigger of Series Nanowire Detector for Event-Based Photon Number Assignment
Walter Schottky Institut, Technische Universität München（瓦尔特·肖特基研究所，慕尼黑工业大学）；TUM School of Natural Sciences, Technische Universität München（慕尼黑工业大学自然科学院）；Munich Quantum Instruments GmbH（慕尼黑量子仪器有限公司）；TUM School of Computation, Information and Technology, Technische Universität München（慕尼黑工业大学计算、信息与技术学院）；PicoQuant GmbH（皮科量子有限公司）
Single photon detectors are indispensable tools in optics, from fundamental measurements to quantum information processing. The ability of superconducting nanowire single photon detectors to detect single photons with unprecedented efficiency, short dead time and high time resolution over a large frequency range enabled major advances in quantum optics. However, combining near-unity system detection efficiency with high timing performance remains an outstanding challenge. In this work, we show novel superconducting nanowire single photon detectors fabricated on membranes with 94-99.5 (plus min…
Single Photon Detectors (SPD) are fundamental to quantum optics and quantum information. Superconducting Nanowire SPDs (SNSPD) [1] provide high performance in terms of quantum efficiency (QE), dark count rate (DCR) and timing jitter [2], but have limited maximum count rate (MCR) when operated as a free-running mode (FM) detector [3, 4]. However, high count rates are needed for many applications like quantum computing [5] and communication [6], and laser ranging [7]. Here we report the first operation of SNSPDs in a gated mode (GM) that exploits a single photon triggered latching phenomenon to …
We present a time-over-threshold readout technique to count the number of activated pixels from an array of superconducting nanowire single photon detectors (SNSPDs). This technique maintains the intrinsic timing jitter of the individual pixels, places no additional heatload on the cryostat, and retains the intrinsic count rate of the time-tagger. We demonstrate proof-of-principle operation with respect to a four-pixel device. Furthermore, we show that, given some permissible error threshold, the number of pixels that can be reliably read out scales linearly with the intrinsic signal-to-noise …
Superconducting nanowire single-photon detectors are an enabling technology for modern quantum information science and are gaining attractiveness for the most demanding photon counting tasks in other fields. Embedding such detectors in photonic integrated circuits enables additional counting capabilities through nanophotonic functionalization. Here we show how a scalable number of waveguide-integrated superconducting nanowire single-photon detectors can be interfaced with independent fiber optic channels on the same chip. Our plug-and-play detector package is hosted inside a compact and portab…
We present a stable and high-performance fiber-coupled NbTiN superconducting nanowire avalanche photon detector (SNAP). We demonstrate afterpulse-free operation in serially connected two SNAPs (SC-2SNAP), even in the absence of a choke inductor, achieving a 7.7 times faster response speed than standard SSPDs. The SC-2SNAP device showed a system detection efficiency (SDE) of 81.0% with wide bias current margin, a dark count rate of 6.8 counts/s, and full width at half maximum timing jitter of 68 ps, operating at 2.3 K.
Single-photon detectors based on superconducting nanowires (SSPDs or SNSPDs) have rapidly emerged as a highly promising photon-counting technology for infrared wavelengths. These devices offer high efficiency, low dark counts and excellent timing resolution. In this review, we consider the basic SNSPD operating principle and models of device behaviour. We give an overview of the evolution of SNSPD device design and the improvements in performance which have been achieved. We also evaluate device limitations and noise mechanisms. We survey practical refrigeration technologies and optical coupli…
A superconducting single-photon detector based on a niobium nitride nanowire is demonstrated in an optical-fibre-based quantum key distribution test bed operating at a clock rate of 3.3 GHz and a transmission wavelength of 850 nm. The low jitter of the detector leads to significant reduction in the estimated quantum bit error rate and a resultant improvement in the secrecy efficiency compared to previous estimates made by use of silicon single-photon avalanche detectors.
The superconducting nanowire single-photon detector (SNSPD) is a quantum-limit superconducting optical detector based on the Cooper-pair breaking effect by a single photon, which exhibits a higher detection efficiency, lower dark count rate, higher counting rate, and lower timing jitter when compared with those exhibited by its counterparts. SNSPDs have been extensively applied in quantum information processing, including quantum key distribution and optical quantum computation. In this review, we present the requirements of single-photon detectors from quantum information, as well as the prin…
Single-photon detection with high efficiency, high timing resolution, low dark counts and high photon detection-rates is crucial for a wide range of optical measurements. Although efficient detectors have been reported before, combining all performance parameters in a single device remains a challenge. Here, we show a broadband NbTiN superconducting nanowire detector with an efficiency exceeding 92%, over 150MHz photon detection-rate, a dark count-rate below 130Hz, operated in a Gifford-McMahon cryostat. Furthermore, with careful optimization of the detector design and readout electronics, we …
Superconducting nanowire single photon detectors (SNSPDs) have advanced various frontier scientific and technological fields such as quantum key distribution and deep space communications. However, limited by available cooling technology, all past experimental demonstrations have had ground-based applications. In this work we demonstrate a SNSPD system using a hybrid cryocooler compatible with space applications. With a minimum operational temperature of 2.8 K, this SNSPD system presents a maximum system detection efficiency of over 50% and a timing jitter of 48 ps, which paves the way for var…
We explore bright-light control of superconducting nanowire single-photon detectors (SNSPDs) in the shunted configuration (a practical measure to avoid latching). In an experiment, we simulate an illumination pattern the SNSPD would receive in a typical quantum key distribution system under hacking attack. We show that it effectively blinds and controls the SNSPD. The transient blinding illumination lasts for a fraction of a microsecond and produces several deterministic fake clicks during this time. This attack does not lead to elevated timing jitter in the spoofed output pulse, and hence doe…
At the core of an ideal single photon detector is an active material that ideally absorbs and converts photons to discriminable electronic signals. A large active material volume favours high-efficiency absorption, but often at the expense of conversion efficiency, noise, speed and timing accuracy. The present work demonstrates how the concept of coherent perfect absorption can be used to relax this trade-off for a waveguide-integrated superconducting nanowire single photon detector. A very short (8.5$μ$m long) and narrow (8$\times$35nm$^2$) U-shaped NbTiN nanowire atop a silicon-on-insulator …
We report on the design, fabrication and measurement of travelling-wave superconducting nanowire single-photon detectors (SNSPDs) integrated with polycrystalline diamond photonic circuits. We analyze their performance both in the near-infrared wavelength regime around 1600 nm and at 765 nm. Near-IR detection is important for compatibility with the telecommunication infrastructure, while operation in the visible wavelength range is relevant for compatibility with the emission line of silicon vacancy centers in diamond which can be used as efficient single-photon sources. Our detectors feature h…
Superconducting nanowire single-photon detectors (SNSPDs) show near unity efficiency, low dark count rate, and short recovery time. Combining these characteristics with temporal control of SNSPDs broadens their applications as in active de-latching for higher dynamic range counting or temporal filtering for pump-probe spectroscopy or LiDAR. To that end, we demonstrate active gating of an SNSPD with a minimum off-to-on rise time of 2.4 ns and a total gate length of 5.0 ns. We show how the rise time depends on the inductance of the detector in combination with the control electronics. The gate w…
Characterization and Active Control of Position-Dependent Timing Dynamics in Superconducting Strip Single-Photon Detectors
NASA Jet Propulsion Laboratory, California Institute of Technology（美国国家航空航天局喷气推进实验室，加州理工学院）；Department of Applied Physics and Material Science, California Institute of Technology（加州理工学院应用物理与材料科学系）；National Institute of Standards and Technology（美国国家标准与技术研究院）；Department of Applied Physics Quantum Technologies, Université de Genève（日内瓦大学应用物理量子技术系）
Single-photon detectors (SPDs) at near infrared wavelengths with high system detection efficiency (> 90%), low dark count rate (< 1 counts per second, cps), low timing jitter (< 100 ps), and short reset time (< 100 ns) would enable landmark experiments in a variety of fields. Although some of the existing approaches to single-photon detection fulfill one or two of the above specifications, to date no detector has met all of the specifications simultaneously. Here we report on a fiber-coupled single-photon-detection system employing superconducting nanowire single photon detectors (SNSPDs) that…
Reaching the intrinsic performance limits of superconducting nanowire single-photon detectors up to 0.1 mm wide
National Institute of Standards and Technology（美国国家标准与技术研究院）；University of Colorado（科罗拉多大学）；California Institute of Technology（加州理工学院）；Jet Propulsion Laboratory, California Institute of Technology（加州理工学院喷气推进实验室）；University of Glasgow（格拉斯哥大学）；Massachusetts Institute of Technology（麻省理工学院）；Old Dominion University（老道明大学）
We experimentally demonstrate a high-fidelity entanglement swapping and a generation of the Greenberger-Horne-Zeilinger~(GHZ) state using polarization-entangled photon pairs at telecommunication wavelength produced by spontaneous parametric down conversion with continuous-wave pump light. While spatially separated sources asynchronously emit photon pairs, the time-resolved photon detection guarantees the temporal indistinguishability of photons without active timing synchronizations of pump lasers and/or adjustment of optical paths. In the experiment, photons are sufficiently narrowed by fiber…
Superconducting nanowire single-photon detectors (SNSPDs) are a leading detector type for time correlated single photon counting, especially in the near-infrared. When operated at high count rates, SNSPDs exhibit increased timing jitter caused by internal device properties and features of the RF amplification chain. Variations in RF pulse height and shape lead to variations in the latency of timing measurements. To compensate for this, we demonstrate a calibration method that correlates delays in detection events with the time elapsed between pulses. The increase in jitter at high rates can be…
Photonic quantum technologies promise to repeat the success of integrated nanophotonic circuits in non-classical applications. Using linear optical elements, quantum optical computations can be performed with integrated optical circuits and thus allow for overcoming existing limitations in terms of scalability. Besides passive optical devices for realizing photonic quantum gates, active elements such as single photon sources and single photon detectors are essential ingredients for future optical quantum circuits. Material systems which allow for the monolithic integration of all components ar…
Improved Cryogenic Photodiode Optical Biasing for Low-Noise and Low-Jitter Superconducting Nanowire Single-Photon Detectors
State Key Laboratory of Materials for Integrated Circuits, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences (CAS)（集成电路材料重点实验室，中国科学院上海微系统与信息技术研究所）；Shanghai Key Laboratory of Superconductor Integrated Circuit Technology, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences（超导集成电路技术上海市重点实验室，中国科学院上海微系统与信息技术研究所）；Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences（中国科学院大学材料科学与光电工程学院）；State Key Laboratory of Analog and Mixed-Signal VLSI, Institute of Microelectronics, and FST ECE, University of Macau（模拟与混合信号超大规模集成电路国家重点实验室，澳门大学微电子研究所及理学院电子计算机工程）
Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. High photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides which allows us to drastically increase t…
We report a compact, scalable, and high-performance superconducting nanowire single-photon detector (SNSPD) array by using a multichannel optical fiber array-coupled configuration. For single pixels with an active area of 18 um in diameter and illuminated at the telecom wavelength of 1550 nm, we achieved a pixel yield of 13/16 on one chip, an average system detection efficiency of 69% at a dark count rate of 160 cps, a minimum timing jitter of 74 ps, and a maximum count rate of ~40 Mcps. The optical crosstalk coefficient between adjacent channels is better than -60 dB. The performance of the f…
Single-photon detection via absorption in current-biased nanoscale superconducting structures has become a preferred technology in quantum optics and related fields. Single-mode fiber packaged devices have seen new records set in detection efficiency, timing jitter, recovery times, and largest sustainable count rates. The popular approaches to decreasing polarization sensitivity have thus far been limited to introduction of geometrically symmetric nanowire meanders, such as spirals and fractals, in the active area. The constraints on bending radii, and by extension, fill factors, in such desig…
The generation, manipulation and detection of quantum bits (qubits) encoded on single photons is at the heart of quantum communication and optical quantum information processing. The combination of single-photon sources, passive optical circuits and single-photon detectors enables quantum repeaters and qubit amplifiers, and also forms the basis of all-optical quantum gates and of linear-optics quantum computing. However, the monolithic integration of sources, waveguides and detectors on the same chip, as needed for scaling to meaningful number of qubits, is very challenging, and previous work …
Quantum key distribution (QKD) offers an unconditionally secure means of communication based on the laws of quantum mechanics. Currently, a major challenge is to achieve a QKD system with a 40 dB channel loss, which is required if we are to realize global scale QKD networks using communication satellites. Here we report the first QKD experiment in which secure keys were distributed over 42 dB channel loss and 200 km of optical fibre. We employed the differential phase shift quantum key distribution (DPS-QKD) protocol implemented with a 10-GHz clock frequency, and superconducting single photon …
