165 research outputs found
High intrinsic energy resolution photon number resolving detectors
Transition Edge Sensors (TESs) are characterized by the intrinsic figure of
merit to resolve both the energy and the statistical distribution of the
incident photons. These properties lead TES devices to become the best single
photon detector for quantum technology experiments. For a TES based on titanium
and gold has been reached, at telecommunication wavelength, an unprecedented
intrinsic energy resolution (0.113 eV). The uncertainties analysis of both
energy resolution and photon state assignment has been discussed. The thermal
properties of the superconductive device have been studied by fitting the bias
curve to evaluate theoretical limit of the energy resolution
Single-photon light detection with transition-edge sensors
Transition-Edge Sensors (TESs) are microcalorimeters that measure the energy of incident single photons by the resistance increase of a superconducting film biased within the superconducting-to-normal transition. TES are able to detect single photons from IR to X-ray with an intrinsic energy resolution and photon-number discrimination capability. Metrology, astronomy and quantum
communication are the fields where these properties can be particularly useful. In this work, we report about characterization of different TESs based on Ti films. Single photons have been detected from 200nm to 800 nm working at transition temperature Tc ⌠100 mK. Using a pulsed laser at 690nm we have demonstrated the capability to resolve up to five photons
E-beam evaporated ZnO thin films: Fabrication and characterization as UV detector
partially_open5In the present paper, fabrication and structural, optical and electrical characterization of ZnO thin films grown by electron gun technique are reported and the performances of a prototype of UV photodetector based on them are illustrated. ZnO thin films, fabricated on sapphire by e-beam evaporation followed by a two-step ex situ treatment (annealing and oxidation), are polycrystalline, with a smooth surface and show very good visible transparency and an energy gap of 3.2 eV. Preliminary results on fabrication and characterization of an UV detector are reported. The Al interdigitated contacts show a Schottky behavior, which is strongly desired in view of applications since it has many advantages in the aspects of high quantum efficiency, response time, low dark current, high UV/visible contrast and possible zero-bias operation.partially_openPortesi C; Lolli L; Taralli E; Rajteri M; Monticone EPortesi, Chiara; Lolli, L; Taralli, Emanuele; Rajteri, Mauro; Monticone, Eugeni
Towards joint reconstruction of noise and losses in quantum channels
The calibration of a quantum channel, i.e. the determination of the
transmission losses affecting it, is definitely one of the principal objectives
in both the quantum communication and quantum metrology frameworks. Another
task of the utmost relevance is the identification, e.g. by extracting its
photon number distribution, of the noise potentially present in the channel.
Here we present a protocol, based on the response of a photon-number-resolving
detector at different quantum efficiencies, able to accomplish both of these
tasks at once, providing with a single measurement an estimate of the
transmission losses as well as the photon statistics of the noise present in
the exploited quantum channel. We show and discuss the experimental results
obtained in the practical implementation of such protocol, with different kinds
and levels of noise.Comment: 6 pages, 4 figure
Self consistent, absolute calibration technique for photon number resolving detectors
Well characterized photon number resolving detectors are a requirement for
many applications ranging from quantum information and quantum metrology to the
foundations of quantum mechanics. This prompts the necessity for reliable
calibration techniques at the single photon level. In this paper we propose an
innovative absolute calibration technique for photon number resolving
detectors, using a pulsed heralded photon source based on parametric down
conversion. The technique, being absolute, does not require reference standards
and is independent upon the performances of the heralding detector. The method
provides the results of quantum efficiency for the heralded detector as a
function of detected photon numbers. Furthermore, we prove its validity by
performing the calibration of a Transition Edge Sensor based detector, a real
photon number resolving detector that has recently demonstrated its
effectiveness in various quantum information protocols.Comment: 9 pages, 2 figure
Quantum and classical characterization of single/few photon detectors
This paper's purpose is to review the results recently obtained in the
Quantum Optics labs of the National Institute of Metrological Research (INRIM)
in the field of single- and few-photon detectors calibration, from both the
classical and quantum viewpoint. In the first part of the paper is presented
the calibration of a single-photon detector with absolute methods, while in the
second part we focus on photon-number-resolving detectors, discussing both the
classical and quantum characterization of such devices.Comment: Quantum Matter in pres
Superconducting Qubit Network as a Single Microwave Photon Detector for Galactic Axion Search
Experimental search of galactic axions requires detection of single photons in the microwave range. We work on a novel approach to detect single microwave photons based on a coherent collective response of quantum states occurring in a superconducting qubit network (SQN) embedded in a low-dissipative superconducting resonator. We propose a two resonators detector configuration with two parallel resonators without common part and with separated input and output terminals. The device consists of a low-dissipative resonator with embedded SQN in which microwave photons arrive (âsignal resonatorâ), and a transmission line for measuring the frequency dependent transmission coefficient demonstrating resonant drops at the qubit frequencies (âreadout resonatorâ). In comparison with T-type three terminal device recently proposed and investigated by us, the device with two resonators with separated input and output terminals doesnât contain common part of both resonators and exclude an unwanted noise from measurement readout circuits to the signal resonator. A layout of two resonators four terminal SQN detectors containing 5 flux
qubits weakly coupled to a low-dissipative signal and readout resonator was developed and optimized. The samples were fabricated by Manhattan Al-based technology with Nb resonator circuits. The SQN detector was experimentally tested in terms of microwave measurements of scattering parameters of both resonators and crosstalk properties. Comparison of experimental data with results of the simulations permits one to conclude that the electromagnetic conditions of the fundamental resonant peak of 8.5 GHz of both resonators arenât affected by the crosstalk phenomenon and their performances provided by the design remain not altered for correct device operation
Investigation of Ti/Au Transition-Edge Sensors for Single-Photon Detection
Transition-edge sensors (TES) are remarkable superconducting devices for a wide range of radiation detection with the ability of both energy resolution and counting photons. For the detection of single photons at telecom wavelength, optical Ti/Au bilayer TESs are fabricated and characterized. The superconducting transition temperature (T-c) of the Ti/Au films is effectively tuned from 162 to 72 mK by increasing the relative thickness ratio between the Au and Ti layer. The sensitive area is 20 mu m x 20 mu m, on which an SiO2/SiNx antireflection structure is coated by an ICP-PECVD process. The TES device shows an energy resolution of 0.19 eV and can discriminate up to 36 incident photons, with an effective time constant around 107 mu s at 95 mK
Coherent Quantum Network of Superconducting Qubits as a Highly Sensitive Detector of Microwave Photons for Searching of Galactic Axions
We propose a novel approach to detect a low power microwave signal with a frequency of the order of several GHz based on a coherent collective response of quantum states occurring in a superconducting qubits network (SQN). An SQN composes of a large number of superconducting qubits embedded in a low-dissipative superconducting resonator. Our theory predicts that an SQN interacting with the off-resonance microwave radiation, demonstrates the collective alternating current Stark effect that can be measured even in the limit of single photon counting. A design of the layout of three terminals SQN detectors containing 10 flux qubits weakly coupled to a low-dissipative R-resonator and T-transmission line was developed. The samples were fabricated by Al-based technology with Nb resonator. The SQN detector was tested in terms of microwave measurements of scattering parameters and two-tone spectroscopy. A substantial shift of the frequency position of the transmission coefficient drop induced by a second tone pump signal was observed, and this effect clearly manifests a nonlinear multiphoton interaction between the second-tone microwave pump signal and an array of qubits
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