Abstract:

Quantum Ghost Imaging (QGI) is a powerful imaging technique that enables probing of an object using illumination levels beyond classical limits and does not rely on a single-photon-sensitive camera in the spectrum of interest. Current “heralded” QGI setups provide high-resolution images with intensified charge-coupled device (ICCD) cameras, but their acquisition time and applicability are limited by setup complexity and detector dead time. Recently, new setups using single photon detection and time-tagging have been shown to allow more efficient acquisition while also enabling new applications, such as remote 3D imaging using “asynchronous” QGI. Here, we demonstrate novel results of two asynchronous QGI setups, using a dedicated high duty-cycle single photon avalanche diode array to drastically reduce acquisition time to sub-second regime, demonstrating video acquisition at 10 fps. As this scheme allows interoperability with arbitrary single photon timing detectors, it can be adapted to a variety of applications and is not bound by the detection window of silicon-based detectors. We further study the impact of the choice of bucket detector and pump laser, using readily available off-the-shelf detectors and lasers. Summarizing the findings, we discuss the remaining limitations for real-time imaging and give an outlook on upcoming developments and an outline of further applications of both detectors and detection scheme.

Authors: Carsten Pitsch, Alessia Suprano, Benjamin Guery, Francesco Poggiali, Chiara Michelini, Henri Haka, Davide Moschella, Dominik Walter, Ugo Zanforlin, Massimiliano Proietti, Massimiliano Dispenza, Alberto Tosi, Federica Villa

Publication location: APL Photonics

Date of publication: 1 October 2025

D.O.I: https://doi.org/10.1063/5.0284755

How to cite this article: Carsten Pitsch, Alessia Suprano, Benjamin Guery, Francesco Poggiali, Chiara Michelini, Henri Haka, Davide Moschella, Dominik Walter, Ugo Zanforlin, Massimiliano Proietti, Massimiliano Dispenza, Alberto Tosi, Federica Villa; Toward video-rate quantum ghost imaging. APL Photonics 1 October 2025; 10 (10): 100801. https://doi.org/10.1063/5.0284755

Abstract:

The intensity noise of a laser source represents one of the key factors limiting the ultimate sensitivity in laser-based systems for sensing and telecommunication. For advanced applications based on interferometry, the availability of a shot-noise-limited local oscillator is even more important for the effective feasibility of high-precision measurements. This is particularly crucial in quantum optics applications based on homodyne detection schemes to measure non-classical light states, such as squeezed states. This work deeply investigates and analyzes the intensity noise features of the most widely used mid-infrared semiconductor heterostructured lasers: quantum cascade and interband cascade lasers. For this purpose, a comprehensive comparison of three different continuous-wave lasers operating at room temperature around 4.5 µm wavelength is presented. First, a thorough electro-optical characterization is given, highlighting the differences and the shared common characteristics of the tested devices. Then, a detailed intensity noise analysis is reported, identifying their different noise operations with a particular reference to shot-noise-limited operations. Finally, some perspectives towards advanced applications are discussed.

Authors: B. Kaczmarczuk, J. Gomes Baptista, S. Merlet, L. A. Sidorenkov, Q. Beaufils and F. Pereira Dos Santos

Publication location: Optics Express

Date of publication: 25 August 2025

D.O.I: https://doi.org/10.1364/OE.549282

How to cite this article: Tecla Gabbrielli, Jacopo Pelini, Georg Marschick, Luigi Consolino, Irene La Penna, Jérôme Faist, Mathieu Bertrand, Filippos Kapsalidis, Robert Weih, Sven Höfling, Naota Akikusa, Borislav Hinkov, Paolo De Natale, Francesco Cappelli, and Simone Borri, “Shot-noise-limited emission from interband and quantum cascade lasers,” Opt. Express 33, 35620-35634 (2025)

Abstract:

We present a statistical analysis of the measurement noise of a atom interferometer (AI) under large phase and contrast noise caused by rotation fluctuations. The extraction of the standard deviation of the contrast fluctuations out of transition probability measurements allows us to determine the level of rotation noise applied to the onboard instrument. We include an experimental validation of the method.

Authors: B. Kaczmarczuk, J. Gomes Baptista, S. Merlet, L. A. Sidorenkov, Q. Beaufils and F. Pereira Dos Santos

Publication location: IEEE Sensors Journal

Date of publication: 15 August 2025

D.O.I: https://doi.org/10.1109/JSEN.2025.3586409

How to cite this article: B. Kaczmarczuk, J. Gomes Baptista, S. Merlet, L. A. Sidorenkov, Q. Beaufils and F. Pereira Dos Santos, “Statistical Analysis of the Rotation Induced Decay of the Contrast in an Onboard Atom Interferometer,” in IEEE Sensors Journal, vol. 25, no. 16, pp. 30889-30896, 15 Aug.15, 2025, doi: 10.1109/JSEN.2025.3586409. 

Abstract:

Authors: P. Knittel, P. Haas, N. Lang, N. Mathes, V. Cimalla, M. Kunzer

Publication location: Proc. SPIE 13202, Quantum Technologies for Defence and Security

Date of publication: 15 November 2024

D.O.I: https://doi.org/10.1117/12.3038043

How to cite this article: P. Knittel, P. Haas, N. Lang, N. Mathes, V. Cimalla, M. Kunzer, “Diamond-based quantum sensors in defence and security applications,” Proc. SPIE 13202, Quantum Technologies for Defence and Security, 132020B (15 November 2024); https://doi.org/10.1117/12.3038043

Abstract:

We present an advanced quantum ghost imaging (QGI) setup that enables low-noise, three-dimensional imaging and ranging of distant objects. A key technical innovation is asynchronous detection by independent single photon detectors, which significantly simplifies existing setups and allows imaging at arbitrary distances. Recent experimental results demonstrate low-noise imaging and efficient object ranging. An important quantum advantage with regard to secure active sensing is indistinguishability from background noise for external parties.

Authors: Dominik Walter and Carsten Pitsch

Publication location: Quantum Technologies for Defence and Security (Proc. SPIE 13202)

Date of publication: 15 November 2024

D.O.I: https://doi.org/10.1117/12.3031683

How to cite this article: P. Dominik Walter and Carsten Pitsch “Quantum remote sensing”, Proc. SPIE 13202, Quantum Technologies for Defence and Security, 1320205 (15 November 2024); https://doi.org/10.1117/12.3031683 

Abstract:

We investigate the activation yield and optical properties of the negatively charged nitrogen-vacancy (NV ⁻) and silicon-vacancy (SiV ⁻) centers in single-crystal diamonds, focusing on the effect of proton (p) and carbon-ion (C) irradiation on their formation. The samples, either nitrogen-rich or silicon-implanted, are grown by chemical vapor deposition or high pressure–high temperature synthesis. They are irradiated over three orders of magnitude in fluence, up to ∼10¹⁴C/cm² or ∼ 10¹⁶ p/cm², generating up to ∼10⁴ ppm of extra vacancies at the end-of-range. Following thermal annealing at 1150 °C for 1 h, we characterize the samples using time-resolved spectroscopy, optical spectroscopy, and optically detected magnetic resonance. The optical properties of the NV ⁻ and SiV⁻ centers remain stable even at vacancy concentrations of ∼10³–10⁴ ppm. At the same time, the activation yield of substitutional nitrogen and (primarily) interstitial silicon increases significantly with vacancy density, from below 2 % to approximately 15–20 % for both centers. A statistical model of defect dynamics during annealing accounts for these results, showing that the activation yield follows a logarithmic dependence on local vacancy concentration—extending over three decades for NV ⁻ and two for SiV ⁻.

Authors: Stefano Lagomarsino, Nemanja Markešević, Zeeshan Rashid, Assegid Mengistu Flatae, Sven Mägdefessel, Santiago Hernández-Gómez, Giovanni Bianchini, Florian Sledz, Nicla Gelli, Lorenzo Giuntini, Mirko Massi, Silvio Sciortino, Chiara Corsi, Volker Cimalla, Peter Knittel, Michael Kunzer, Marco Bellini, Nicole Fabbri, Mario Agio

Publication location: Diamond and Related Materials

Date of publication: October 2025

D.O.I: https://doi.org/10.1016/j.diamond.2025.112632

How to cite this article: Stefano Lagomarsino, Nemanja Markešević, Zeeshan Rashid, Assegid Mengistu Flatae, Sven Mägdefessel, Santiago Hernández-Gómez, Giovanni Bianchini, Florian Sledz, Nicla Gelli, Lorenzo Giuntini, Mirko Massi, Silvio Sciortino, Chiara Corsi, Volker Cimalla, Peter Knittel, Michael Kunzer, Marco Bellini, Nicole Fabbri, Mario Agio, Enhanced activation yield of nitrogen-vacancy and silicon-vacancy diamond color centers by proton and carbon irradiation, Diamond and Related Materials, Volume 158, 2025, 112632, ISSN 0925-9635, https://doi.org/10.1016/j.diamond.2025.112632

Abstract:

Our work investigates the generation of non-classical light by cascade lasers in the mid-infrared (MIR, 3–5μm) spectral region. Using a MIR-balanced detector sensitive to the intensity noise below the classical level, we demonstrated shot-noise-limited operations of MIR cascade lasers. The same setup was exploited to measure four-wave-mixing-induced correlations between modes in harmonic combs emitted by these devices. Moreover, we recently tested the electron-to-photon noise transfer function in cascade lasers, paving the way to control their emissions down to the quantum level. These novel insights should make laser sensing possible at unprecedented sensitivity levels.

Authors: Tecla Gabbrielli, Jacopo Pelini, Irene La Penna, Luigi Consolino, Davide Mazzotti, Francesco Cappelli, Paolo De Natale, Simone Borri

Publication location: Proc. SPIE 13376, Quantum Sensing and Nano Electronics and Photonics XXI

Date of publication: 21 March 2025

D.O.I: https://doi.org/10.1117/12.3050152

How to cite this article: Tecla Gabbrielli, Jacopo Pelini, Irene La Penna, Luigi Consolino, Davide Mazzotti, Francesco Cappelli, Paolo De Natale, Simone Borri, “Quantum and interband cascade lasers between classical and quantum operation regime,” Proc. SPIE 13376, Quantum Sensing and Nano Electronics and Photonics XXI, 133760I (21 March 2025); https://doi.org/10.1117/12.3050152

Abstract:

The implementation of free-space optical communication and sensing systems at mid-IR wavelengths represents a critical advancement for next-generation high-speed communication networks, offering a robust solution for environments where traditional radio frequency (RF) and near-IR systems face significant limitations. Here we report on our recent advancements in free-space optical communication and sensing using mid-IR quantum cascade lasers (QCLs). Two setups are discussed, one using a QCL comb for optical communication in the 4-μm atmospheric transparency window and one LIDAR based on single-mode cw QCL for range finding and air quality analysis. Experimental results demonstrating few-photon coherent detection will be shown.

Authors: Simone Borri, Tecla Gabbrielli, Jacopo Pelini, Luigi Consolino, Davide Mazzotti, Lorenzo Mischi, Nicola Corrias, Giovanni Bianchini, Paolo De Natale, Francesco Cappelli

Publication location: Proc. SPIE 13376, Quantum Sensing and Nano Electronics and Photonics XXI

Date of publication: 21 March 2025

D.O.I: https://doi.org/10.1117/12.3050483

How to cite this article: Simone Borri, Tecla Gabbrielli, Jacopo Pelini, Luigi Consolino, Davide Mazzotti, Lorenzo Mischi, Nicola Corrias, Giovanni Bianchini, Paolo De Natale, Francesco Cappelli, “Free-space communication and remote sensing using mid-infrared quantum cascade lasers down to few-photon light level,” Proc. SPIE 13376, Quantum Sensing and Nano Electronics and Photonics XXI, 1337603 (21 March 2025); https://doi.org/10.1117/12.3050483

Abstract:

We report on the development and short-term stability characterization of an optical frequency reference based on the spectroscopy of the rubidium two-photon transition at 778 nm in a microfabricated vapor cell. When compared against a 778 nm reference signal extracted from a frequency-doubled cavity-stabilized telecom laser, the short-term stability of the microcell frequency standard is  until 200 s, in good agreement with a phase noise level of  at 1 Hz offset frequency. The two main contributions to the short-term stability of the microcell reference are currently the photon shot noise and the intermodulation effect induced by the laser frequency noise. Retaining a relevant margin of progress, these results show the interest of this spectroscopic approach for the demonstration of high-stability miniaturized optical vapor cell clocks. Such clocks are poised to be highly beneficial for applications in navigation, communications, and metrology.

Authors: Martin Callejo, Andrei Mursa, Rémy Vicarini, Emmanuel Klinger, Quentin Tanguy, Jacques Millo, Nicolas Passilly, and Rodolphe Boudot

Publication location: Journal of the Optical Society of America B

Date of publication: 19 December 2024

D.O.I: https://doi.org/10.1364/JOSAB.533904

How to cite this article: Martin Callejo, Andrei Mursa, Rémy Vicarini, Emmanuel Klinger, Quentin Tanguy, Jacques Millo, Nicolas Passilly, and Rodolphe Boudot, “Short-term stability of a microcell optical reference based on the Rb atom two-photon transition at 778 nm,” J. Opt. Soc. Am. B 42, 151-159 (2025)

Abstract:

In this paper, we present a realization of an on chip atomic clock using a cold cloud of 87Rb atoms. This clock is based on a Ramsey interferometer with a Ramsey time around 600 ms. This is realized with large laboratory temperature drift during the measurement (few degrees per day) and without magnetic-field shielding. We review the experimental implementation of this clock and give a full study of the known noises present in this atomic clock.

Authors: M. Dupont-Nivet, B. Wirtschafter, S. Hello, C. I. Westbrook

Publication location: Phys. Rev. A

Date of publication: 12 June 2025

D.O.I: 

https://doi.org/10.1103/PhysRevA.111.063106

How to cite this article: 

Dupont-Nivet, M., Wirtschafter, B., Hello, S., Westbrook, C. I. Noise budget of a trapped on-chip cold-atom.  American Physical Society. https://link.aps.org/doi/10.1103/PhysRevA.111.063106