Quantum Optics INRIM
Quantum Photonics Metrology
There is now a critical mass of companies developing quantum photonics technologies ranging from quantum communications (e.g. single-photon sources and sources of entangled photons for quantum key distribution) via quantum sensors (e.g. single-photon detectors, but also magnetic, temperature and pressure sensors based on NV centres) to quantum imaging (e.g. single photon confocal microscope and quantum cameras). It is fundamental that dedicated metrological techniques should be developed to support the standardisation and the market success of these novel technologies.
The Quantum Optics Group contributes by developing cutting edge research activities in the context of optically based quantum enhance measurements and quantum sensors, as well as, developing the necessary metrological infrastructure for the characterisation of the quantum photonics devices and for their certification.
Specifically, it has developed novel measurement approach and systems for the characterisation of several aspects of single-photon sources and single-photon detectors.
Furthermore, there is an extremely active research field aiming at developing quantum sensors exploiting fluorescence of the colour centres in (nano-)diamond, and a strong interest in developing quantum enhanced measurement systems exploiting quantum light in a variety of field ranging from quantum interferometry to quantum reading.
Detection of ultra-weak laser pulses by free-running single-photon detectors: Modeling dead time and dark counts effects
In quantum communication systems, the precise estimation of the detector´s response to the incoming light is necessary to avoid security breaches. The typical working regime uses a free-running single-photon avalanche diode in combination with attenuated laser pulses at telecom wavelength for encoding information. We demonstrate the validity of an analytical model for this regime that considers the effects of dark counts and dead time on the measured count rate. For the purpose of gaining a better understanding of these effects, the photon detections were separated from the dark counts via a software-induced gating mechanism. The model was verified by experimental data for mean photon numbers covering three orders of magnitude as well as for laser repetition frequencies below and above the inverse dead time. Consequently, our model would be of interest for predicting the detector response not only in the field of quantum communications, but also in any other quantum physics experiment where high detection rates are needed.
Towards a standard procedure for the measurement of the multi-photon component in a CW telecom heralded single-photon source
Single-photon sources are set to be a fundamental tool for metrological applications as well as for quantum information related technologies. Because of their upcoming widespread dissemination, the need for their characterization and standardization is becoming of the utmost importance. Here, we illustrate a strategy to provide a quantitative estimate of the multi-photon component of a single-photon source, showing the results achieved in a pilot study for the measurement of the second-order autocorrelation function g(2)(0) of a low-noise CW heralded single photon source prototype (operating at telecom wavelength nm) realized in INRiM. The results of this pilot study, involving INRiM, NPL and PTB, will help to build a robust and unambiguous procedure for the characterization of the emission of a single-photon source.
Most relevant pubblications
Hristina Georgieva et al. "Detection of ultra-weak laser pulses by free-running single-photon detectors: Modeling dead time and dark counts effects" Applied Physics Letters 118, 174002 (2021).
A biocompatible technique for magnetic field sensing at (sub)cellular scale using Nitrogen-Vacancy centers. E. Bernardi, E. Moreva, P. Traina, G. Petrini, S. Ditalia Tchernij, J. Forneris, Ž. Pastuović, I. P. Degiovanni, P. Olivero and M. Genovese. EPJ Quantum Technol. 7, 13 (2020).
A study to develop a robust method for measuring the detection efficiency of free-running InGaAs/InP single-photon detectors. M. López, A. Meda, G. Porrovecchio, R. A. Starkwood, M. Genovese, G. Brida, M. Šmid, C. J. Chunnilall, I. P. Degiovanni and S. Kück. EPJ Quantum Technol. 7, 14 (2020).
Is a Quantum Biosensing Revolution Approaching? Perspectives in NV‐Assisted Current and Thermal Biosensing in Living Cells. Petrini, G., Moreva, E., Bernardi, E., Traina, P., Tomagra, G., Carabelli, V., Degiovanni, I.P. and Genovese, M. Adv. Quantum Technol., 3: 2000066. (2020).
Towards a standard procedure for the measurement of the multi-photon component in a CW telecom heralded single-photon source. E. Rebufello, F. Piacentini, M. Lopez, R. A. Kirkwood, I. Ruo-Berchera, M. Gramegna, G. Brida, S. Kuck, C. J. Chunnilall, M. Genovese and I. P. Degiovanni. Metrologia 56 (2019) 025004