Because of the possibility of high efficiency and high rate detection of single photons with low dark counts, there is increasing interest in using superconducting optical photon detectors in a variety of applications in quantum information science and technology. I will describe our work on two types of superconducting detectors, the Superconducting Single Photon Detector (SSPD) and superconducting Transition-Edge Sensor (TES).
Because of the possibility of high efficiency and high rate detection of single photons with low dark counts, there is increasing interest in using superconducting optical photon detectors in a variety of applications in quantum information science and technology. I will describe our work on two types of superconducting detectors, the Superconducting Single Photon Detector (SSPD) and superconducting Transition-Edge Sensor (TES).
There is increasing interest in using superconducting optical photon detectors in a variety of applications. These applications require detectors that have extremely low dark count rates, high count rates, and high quantum efficiency. I will describe our work on two types of superconducting detectors, the Superconducting Nanowire Single Photon Detector (SNSPD or nSSPD) and superconducting Transition-Edge Sensor (TES). An SNSPD is an ultra-thin, ultra-narrow (nm scale) superconducting meander that is current biased just below its critical current density. When one or more photon is absorbed, a hot spot is formed that causes the superconductor to develop a resistance and consequently a voltage pulse. At NIST and JPL, we have been developing nanowire detectors using an amorphous alloy of tungsten-silicide. An example of this detector is shown in Fig 1(a). In this case, there are two tungsten silicide layers separated by a dielectric layer to optimize detection of light for any polarization[1]. Fig 1(b) is an example of a TES detector with gold cooling fins to enhance timing of the detector[2]. By exploiting the sharp superconducting-to-normal resistive transition of tungsten at 100mK, TES detectors give an output signal that is proportional to the cumulative energy in an absorption event. This proportional pulse-height enables the determination of the energy absorbed by the TES and the direct conversion of sensor pulse-height into photon number. I will discuss our progress towards developing both types of detectors with quantum efficiencies approaching 100%.
Over the past decade, there have been increasing demand on and interest in high performance single photon detectors in many new applications in quantum information technology. Compared with conventional single photon detectors, superconducting transition edge sensor (TES) based single photon detectors have great advantages in the performance of detection efficiency, energy resolution, photon number resolving capability, dark count rate, etc. They have been successfully used in quantum optics experiments and quantum key distribution systems, and they will play a more important role in the research field of quantum information science and technology. In this paper we review the operating principle, fabrication process, performance, measurement system and the research progress on superconducting TES based single photon detectors.
There is increasing interest in using high-performance cryogenic optical photon detectors in a variety of applications in quantum information science and technology. These applications require detectors that have extremely low dark count rates, high photon count rates, high quantum efficiency, and moderate energy resolution or photon number resolution for near-infrared and optical photons. In this paper, we describe the operation, fabrication, and performance of superconducting transition-edge sensors designed for quantum optics and information applications.
There is increasing interest in using high-performance cryogenic optical photon detectors in a variety of applications in quantum information science and technology. These applications require detectors that have extremely low dark count rates, high photon count rates, high quantum efficiency, and moderate energy resolution or photon number resolution for near-infrared and optical photons. In this paper, we describe the operation, fabrication, and performance of superconducting transition-edge sensors designed for quantum optics and information applications.
Superconducting devices offer the potential to perform at speeds and detection efficiencies higher than what is possible using conventional technologies (such as semiconducting avalanche photodiodes and photomultiplier tubs) for wavelengths from the ultraviolet to the mid-infrared. As a result, there has been increasing interest in using superconducting optical photon detectors in a variety of applications. There has been significant progress in using these types of detectors in areas of basic research such as quantum information science and quantum optics. These applications require detectors that have extremely low dark count rates, high count rates, and high quantum efficiency. I will begin by describing some of our earlier work on superconducting Transition-Edge Sensor (TES). In particular, I will describe some of the engineering involved in the cryogenic, electrical, and optical packaging so that these devices can be easily coupled into fiber-based optics. I will also describe our recent work on developing superconducting nanowire single photon detectors (SNSPD or SSPD). An SNSPD is an ultra-thin, ultra-narrow (nm scale) superconducting meander that is current biased just below its critical current density. When one or more photon is absorbed, a hot spot is formed that causes the superconductor to develop a resistance and consequently a voltage pulse. At NIST and JPL, we have been developing nanowire detectors using an amorphous alloy of tungsten-silicide. We will describe to construct systems using tungsten-silicide nanowires to achieve high detection efficiency (>90% at 1550nm). I will also describe our work to improve the performance of the device by fabricating multiple nanowires in an electrically parallel structure to implement a superconducting nanowire avalanche photodiode (SNAP)[1]. One example of this type of detector is shown in Fig 1. In this case, there are two tungsten silicide layers separated by a dielectric layer to optimize detection of light for any polarization[2]. In addition, progress on other types of SNAP detectors will be described to increase the signal size from a single photon, reduce the recovery time of the device, and to improve the jitter.
Superconducting single-photon detectors have been shown to have extremely high detection efficiency over a large wavelength range, typically exceeding 90 % [1, 2]. Their use in quantum and classical optics is becoming more and more widespread in part due to improvements to and ease of use of the cryogenic packaging. In this talk, we will review two superconducting detector technologies, the superconducting nanowire single-photon detector (SNSPD) and the optical transition-edge sensor (TES) [3], that are being developed at NIST. We will also describe their applications in quantum and classical optics and present our recent effort to use these detectors as calibration standards, as well as our effort to establish a single-photon detector calibration service. Superconducting Nanowire Single Photon Detectors The SNSPD is based on a meandering, narrow, thin superconducting nanowire, current-biased close to its critical current. Our SNSPDs operate at temperatures around 1K. When a photon is absorbed in the detection region, the energy deposited drives the wire normal and a voltage pulse can be observed. Due to the speed of the detection process, the SNSPD offers high timing resolution along with detection of the photon flux at the shot-noise limit. The combination of both these features yields a detector that can measure the photon’s arrival time from a faint object or source. SNSPDs also offer single-photon detection capability beyond the wavelength detection range of silicon and InGaAs, out to at least 5000 nm [4]. SNSPDs were also recently implemented in an 8×8-pixel array enabling low-resolution, real-time imaging [5]. For our calibration service effort, we built an SNSPD system that can be used as a transfer standard between labs for single-photon detector calibrations. Transition Edge Sensors In contrast to the SNSPD, the TES is a photon-number resolving detector that has almost unity detection efficiency. The TES consists of a superconducting thin film, voltage-biased so that its resistance is in the transition between the superconducting regime and the normal conducting regime. The steep slope of the resistive transition allows for small temperature changes to be measured. The TES is designed such that the absorption of a single photon increases the temperature of the superconducting film enough to discern the resulting signal from the TES system noise. Therefore, the TES needs to be electrically and thermally quiet and is generally operated at temperatures around 100 mK. Due to its energy resolving capability, the TES can be also used as a spectrally resolving single-photon detector with limited resolution [6]. The TES can also be operated as a cryogenic radiometer in combination with an electrical substitution method, and can, in principle, yield absolute calibration of optical powers on the order of a few tens of femtowatts [7]. References 1 A. E. Lita, A. J. Miller, and S. W. Nam, Opt. Express 16, 3032 (2008). 2 F. Marsili, et al., Nat Photon 7, 210 (2013). 3 R. Hadfield and G. Johansson, Superconducting Devices in Quantum Optics (Springer, 2016). 4 F. Marsili, et al., in CLEO: 2013 (OSA, San Jose, California, 2013), p. CTu1H.1. 5 M. S. Allman, et al., Applied Physics Letters 106, 192601 (2015). 6 M. Fortsch, et al., Journal of Optics 17, 065501 (2015). 7 N. A. Tomlin, J. H. Lehman, and S. Nam, Optics Letters 37, 2346 (2012).