700 research outputs found
Ti/Au TES as photon-number–resolving detector
One of the most promising detector, able to resolve single photons thanks to their intrinsic energy resolution, is the transition-edge sensor (TES). We present the state of the art on these superconducting single-photon detectors, developed and characterised at the National Institute of Metrological Research (INRIM). We show both the physical properties and the best results obtained on a Ti/Au TES in the spectral range between visible and near infrared
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
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
Multispectral pansharpening with radiative transfer-based detail-injection modeling for preserving changes in vegetation cover
Whenever vegetated areas are monitored over time, phenological changes in land cover should be decoupled from changes in acquisition conditions, like atmospheric components, Sun and satellite heights and imaging instrument. This especially holds when the multispectral (MS) bands are sharpened for spatial resolution enhancement by means of a panchromatic (Pan) image of higher resolution, a process referred to as pansharpening. In this paper, we provide evidence that pansharpening of visible/near-infrared (VNIR) bands takes advantage of a correction of the path radiance term introduced by the atmosphere, during the fusion process. This holds whenever the fusion mechanism emulates the radiative transfer model ruling the acquisition of the Earth's surface from space, that is for methods exploiting a multiplicative, or contrast-based, injection model of spatial details extracted from the panchromatic (Pan) image into the interpolated multispectral (MS) bands. The path radiance should be estimated and subtracted from each band before the product by Pan is accomplished. Both empirical and model-based estimation techniques of MS path radiances are compared within the framework of optimized algorithms. Simulations carried out on two GeoEye-1 observations of the same agricultural landscape on different dates highlight that the de-hazing of MS before fusion is beneficial to an accurate detection of seasonal changes in the scene, as measured by the normalized differential vegetation index (NDVI)
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
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