arXiv subjects

Luca Maggio

Publications and source records attributed to Luca Maggio.

7 recordsLinked to original sources

arXiv2026

Multi-parameter two-photon polarimetry at the quantum limit

Photonic quantum metrology has demonstrated advantages in precision and resource efficiency for a wide range of applications, with several schemes approaching the fundamental quantum Cram\'er-Rao precision bound (QCRB). However, the intrinsic incompatibility of quantum measurements represents a hurdle in extending these advantages to the simultaneous estimation of multiple parameters. In this paper, we present an experimental protocol approaching the QCRB simultaneously in two polarisation parameters, across a wide range of the parameter space, with as few as $\sim 200$ photon pairs, offering advantages for polarimetric sensing for dim sources such as in X-ray astronomy or photosensitive samples.

quant-ph↗

arXiv2026

Quantum-limited estimation of the difference between photonic momenta via spatially resolved two-photon interference

We present a quantum sensing protocol for three-dimensional estimation of the difference between the momenta of two photons based on spatially resolved interferometric sampling measurements. The protocol attains ultimate quantum precision in the simultaneous estimation of the components of the relative momentum for any values of the parameters already with $\sim 2000$ sampling measurements and a bias below $1\%$. These results identify 3D spatially resolved two-photon interference as an efficient tool for multi-parameter quantum sensing, with potential applications in high-precision 3D localization, refractometry, and near-field calibration in free-space quantum technologies.

quant-ph↗

arXiv2025

Quantum-limited optical delay sensing across an enhanced dynamic range by frequency-resolving two-photon interference

Optical sensing schemes that rely on two-photon interference provide a powerful platform for precision metrology, although they are inherently constrained by a trade-off between dynamic range and measurement precision. To overcome this limitation, we sample the frequencies of two interfering photons, which extends the sensitivity in the time domain. This enhances the dynamic range of optical delay estimation by up to twenty times compared to the non-resolved estimates. We demonstrate this approach with independent photon sources and show the behaviour of finite frequency resolving detectors. This technique enables scan-free nanometre resolution depth sensing over a millimetre-scale range, with applications in biological and nanomaterial imaging.

quant-ph↗

arXiv2025

Quantum Interference of Distinguishable Photons Based on Spatially-Resolved Measurements

We present experimental results demonstrating the quantum interference of two photons distinguishable in their transverse momenta, each entering the input ports of a balanced beam splitter. This counterintuitive interference effect is made possible through spatially resolved measurements in the near field, i.e., by resolving the conjugate variable in which the photons are distinguishable. Our experimental findings agree with theoretical predictions. We contrast our results with a non-spatially resolved measurement where averaging over the photons' positions washes out the quantum interference observed in spatially resolved measurements.

quant-ph↗

arXiv2025

Ultimate quantum sensitivity in the 3D relative localisation of two single-photon emitters via two-photon interference

We present a quantum sensing protocol for the simultaneous estimation of the difference in the localization parameters of two single-photon sources, paving the way to single-photon 3D imaging and 3D nanoscopy beyond the diffraction limit. This is achieved by exploiting two-photon interference of the two emitted photons at a beam splitter via sampling measurements in the frequency and transverse momenta at the output. We prove theoretically that this technique reaches the ultimate sensitivity in the 3D relative localization of two emitters, already with a number of sampling measurements of 1000 and a bias in the three localization parameters below 1%. These results are independent of the values of the localization parameters to estimate.

quant-ph↗

arXiv2024

Quantum-limited estimation of the frequency shift between two interfering photons by time sampling of their quantum beats

We present a sensing scheme for estimating the frequency difference of two non-entangled photons. The technique consists of time-resolving sampling measurements at the output of a beam splitter. With this protocol, the frequency shift between two photons can be estimated with the ultimate precision achievable in nature, overcoming the limits in precision and the range of detection of frequency-resolving detectors employed in standard direct measurements of the frequencies. The sensitivity can be increased by increasing the coherence time of the photons. We show that, already with $\sim 1000$ sampling measurements, the Cram\'{e}r-Rao bound is saturated independently of the value of the difference in frequency.

quant-ph↗

arXiv2022

Goos-Haenchen lateral displacements and angular deviations: When these optical effects offset each other

For optical beams, transmitted by a right angle prism, the Goos-Haenchen shift can never be seen as a pure effect. Indeed, the lateral displacement, caused by the total internal reflection, will always be accompanied by angular deviations generated by the transmission through the incoming and outgoing interfaces. This combined effect can be analysed by using the Taylor expansion of the Fresnel coefficients. The analytic expression found for the transmitted beam allows to determine the beam parameters, the incidence angles, and the axial distance for which lateral displacements are compensated by angular deviations. Proposals to optimize experimental implementations are also briefly discussed.

physics.optics↗