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Enhanced cooperativity of J-exciton-polaritons in dielectric BIC metasurfaces
Authors:
Marco Marangi,
Alexander M. Dubrovkin,
Anton N. Vetlugin,
Giorgio Adamo,
Cesare Soci
Abstract:
Sources of highly correlated photons are critical for non-linear optics, emerging quantum information, communication and sensing technologies, as well as for fundamental studies of light-matter interaction. A strategy to realize such sources relies on the cooperative coupling of quantum emitters, enabling collective light emission known as superradiance. Here, we demonstrate that organic molecular…
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Sources of highly correlated photons are critical for non-linear optics, emerging quantum information, communication and sensing technologies, as well as for fundamental studies of light-matter interaction. A strategy to realize such sources relies on the cooperative coupling of quantum emitters, enabling collective light emission known as superradiance. Here, we demonstrate that organic molecular J-aggregates exhibit room temperature superradiant emission that transitions to a highly collective regime of ~250 synchronized J-excitons when strongly coupled to delocalized photonic modes of a silicon bound-state-in-the-continuum metasurface. This enhanced cooperativity manifests as a Rabi splitting dependent scaling of both emission rate and intensity, driving the system into a superbunching regime of photon statistics. At the highest excitation density, we observe massively superbunched photon emission with g2(0)>13, unlocking new possibilities for engineering ultrafast, temporally correlated light sources that can operate at room temperature.
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Submitted 11 November, 2025;
originally announced November 2025.
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Fourier State Tomography of Polarization-Encoded Qubits
Authors:
Mohammed K. Alqedra,
Pierre Brosseau,
Ali W. Elshaari,
Jun Gao,
Anton N. Vetlugin,
Cesare Soci,
Val Zwiller
Abstract:
Quantum state tomography is a central technique for the characterization and verification of quantum systems. Standard tomography is widely used for low-dimensional systems, but for larger systems, it becomes impractical due to the exponential scaling of experimental complexity with the number of qubits. Here, we present an experimental realization of Fourier-transform quantum state tomography for…
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Quantum state tomography is a central technique for the characterization and verification of quantum systems. Standard tomography is widely used for low-dimensional systems, but for larger systems, it becomes impractical due to the exponential scaling of experimental complexity with the number of qubits. Here, we present an experimental realization of Fourier-transform quantum state tomography for polarization-encoded photonic states. We validate the technique using weak coherent states and entangled photon pairs generated by a quantum dot and spontaneous parametric down-conversion source in the telecom wavelength. The reconstructed density matrices show excellent agreement with those obtained through conventional projective tomography, with calculated metrics such as fidelity and concurrence matching within error bars, confirming the reliability and accuracy of the technique. Fourier state tomography employs only a single rotating waveplate per qubit, thereby avoiding repeated adjustments across multiple waveplates and ensuring that the number of physical measurement settings scales linearly with the number of qubits, despite the exponential growth of the underlying state space. This reduction in optical configurations simplifies experimental overhead, making Fourier state tomography a practical alternative for multi-qubit characterization.
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Submitted 23 March, 2025;
originally announced March 2025.
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Enhanced quantum magnetometry with a laser-written integrated photonic diamond chip
Authors:
Yanzhao Guo,
Giulio Coccia,
Vinaya Kumar Kavatamane,
Argyro N. Giakoumaki,
Anton N. Vetlugin,
Roberta Ramponi,
Cesare Soci,
Paul E. Barclay,
John P. Hadden,
Anthony J. Bennett,
Shane M. Eaton
Abstract:
An ensemble of negatively charged nitrogen-vacancy centers in diamond can act as a precise quantum sensor even under ambient conditions. In particular, to optimize thier sensitivity, it is crucial to increase the number of spins sampled and maximize their coupling to the detection system, without degrading their spin properties. In this paper, we demonstrate enhanced quantum magnetometry via a hig…
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An ensemble of negatively charged nitrogen-vacancy centers in diamond can act as a precise quantum sensor even under ambient conditions. In particular, to optimize thier sensitivity, it is crucial to increase the number of spins sampled and maximize their coupling to the detection system, without degrading their spin properties. In this paper, we demonstrate enhanced quantum magnetometry via a high-quality buried laser-written waveguide in diamond with a 4.5 ppm density of nitrogen-vacancy centers. We show that the waveguide-coupled nitrogen-vacancy centers exhibit comparable spin coherence properties as that of nitrogen-vacancy centers in pristine diamond using time-domain optically detected magnetic resonance spectroscopy. Waveguide-enhanced magnetic field sensing is demonstrated in a fiber-coupled integrated photonic chip, where probing an increased volume of high-density spins results in 63 pT$.$Hz $^{-1/2}$ of DC-magnetic field sensitivity and 20 pT$.$Hz $^{-1/2}$ of AC magnetic field sensitivity. This on-chip sensor realizes at least an order of magnitude improvement in sensitivity compared to the conventional confocal detection setup, paving the way for microscale sensing with nitrogen-vacancy ensembles.
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Submitted 5 February, 2025; v1 submitted 4 February, 2025;
originally announced February 2025.
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Localization of nanoscale objects with light singularities
Authors:
Thomas A. Grant,
Anton N. Vetlugin,
Eric Plum,
Kevin F. MacDonald,
Nikolay I. Zheludev
Abstract:
Unprecedented atomic-scale measurement resolution has recently been demonstrated in single-shot optical localization metrology based on deep-learning analyses of diffraction patterns of topologically structured light scattered from objects. Here we show that variations in the diffraction patterns caused by positional changes of an object depend upon the spatial derivatives of the magnitude and pha…
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Unprecedented atomic-scale measurement resolution has recently been demonstrated in single-shot optical localization metrology based on deep-learning analyses of diffraction patterns of topologically structured light scattered from objects. Here we show that variations in the diffraction patterns caused by positional changes of an object depend upon the spatial derivatives of the magnitude and phase of the incident field, with the latter strongly enhanced at phase singularities. Despite lower intensity near the singularity, an orders-of-magnitude increase in Fisher information contained in the diffraction patterns can be achieved when a nano-object is illuminated by light containing phase singularities, rather than a plane wave. Our work provides a fundamental explanation and motivation for singularity-based metrology with deeply subwavelength precision.
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Submitted 14 November, 2024;
originally announced November 2024.
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Structured light analogy of squeezed state
Authors:
Zhaoyang Wang,
Ziyu Zhan,
Anton N. Vetlugin,
Qiang Liu,
Yijie Shen,
Xing Fu
Abstract:
Control of structured light is of great importance to explore fundamental physical effects and extend practical scientific applications, which has been advanced by accepting methods of quantum optics - many classical analogies of exotic quantum states were designed using structured modes. However, the prevailing quantum-like structured modes are limited by discrete states where the mode index is a…
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Control of structured light is of great importance to explore fundamental physical effects and extend practical scientific applications, which has been advanced by accepting methods of quantum optics - many classical analogies of exotic quantum states were designed using structured modes. However, the prevailing quantum-like structured modes are limited by discrete states where the mode index is analog to the photon number state. Yet, beyond discrete states, there is a broad range of quantum states to be explored in the field of structured light -- continuous-variable (CV) states. As a typical example of CV states, squeezed state plays a prominent role in high-sensitivity interferometry and gravitational wave detection. In this work, we bring together two seemingly disparate branches of physics, namely, classical structured light and quantum squeezed state. We propose the structured light analogy of squeezed state (SLASS), which can break the spatial limit following the process of surpassing the standard quantum limit (SQL) with quantum squeezed states. This work paves the way for adopting methods from CV quantum states into structured light, opening new research directions of CV entanglement, teleportation, classical and quantum informatics of structured light in the future.
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Submitted 5 October, 2022;
originally announced October 2022.