114 research outputs found
Superconducting Nanowire Single-Photon Detectors for Quantum Information
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 principle, key metrics, latest performance issues and other issues
associated with SNSPD. The representative applications of SNSPDs with respect
to quantum information will also be covered.Comment: 45 pages, 8 figures, 2 tables, accepted by Nanophtonic
Experimental preparation and verification of quantum money
A quantum money scheme enables a trusted bank to provide untrusted users with
verifiable quantum banknotes that cannot be forged. In this work, we report an
experimental demonstration of the preparation and verification of unforgeable
quantum banknotes. We employ a security analysis that takes experimental
imperfections fully into account. We measure a total of states
in one verification round, limiting the forging probability to based
on the security analysis. Our results demonstrate the feasibility of preparing
and verifying quantum banknotes using currently available experimental
techniques.Comment: 12 pages, 4 figure
Jitter analysis of a superconducting nanowire single photon detector
Jitter is one of the key parameters for a superconducting nanowire single
photon detector (SNSPD). Using an optimized time-correlated single photon
counting system for jitter measurement, we extensively studied the dependence
of system jitter on the bias current and working temperature. The
signal-to-noise ratio of the single-photon-response pulse was proven to be an
important factor in system jitter. The final system jitter was reduced to 18 ps
by using a high-critical-current SNSPD, which showed an intrinsic SNSPD jitter
of 15 ps. A laser ranging experiment using a 15-ps SNSPD achieved a record
depth resolution of 3 mm at a wavelength of 1550 nm.Comment: 7 pages, 6 figure
Energy-Time Entanglement-based Dispersive Optics Quantum Key Distribution over Optical Fibers of 20 km
An energy-time entanglement-based dispersive optics quantum key distribution
(DO-QKD) is demonstrated experimentally over optical fibers of 20 km. In the
experiment, the telecom band energy-time entangled photon pairs are generated
through spontaneous four wave mixing in a silicon waveguide. The arrival time
of photons are registered for key generating and security test. High
dimensional encoding in the arrival time of photons is used to increase the
information per coincidence of photon pairs. The bin sifting process is
optimized by a three level structure, which significantly reduces the raw
quantum bit error rate (QBER) due to timing jitters of detectors and
electronics. A raw key generation rate of 151kbps with QBER of 4.95% is
achieved, under a time-bin encoding format with 4 bits per coincidence. This
experiment shows that entanglement-based DO-QKD can be implemented in an
efficient and convenient way, which has great potential in quantum secure
communication networks in the future
A photon counting reconstructive spectrometer combining metasurfaces and superconducting nanowire single-photon detectors
Faint light spectroscopy has many important applications such as fluorescence
spectroscopy, lidar and astronomical observations. However, long measurement
time limit its application on real-time measurement. In this work, a photon
counting reconstructive spectrometer combining metasurfaces and superconducting
nanowire single photon detectors (SNSPDs) was proposed. A prototype device was
fabricated on a silicon on isolator (SOI) substrate, and its performance was
characterized. Experiment results show that this device support spectral
reconstruction of mono-color lights with a resolution of 2 nm in the wavelength
region of 1500 nm ~ 1600 nm. The detection efficiency of this device is 1.4% ~
3.2% in this wavelength region. The measurement time required by this photon
counting reconstructive spectrometer was also investigated experimentally,
showing its potential to be applied in the scenarios requiring real-time
measurement
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