arXiv subjects

Edoardo Charbon

Publications and source records attributed to Edoardo Charbon.

At least 19 recordsLinked to original sources

arXiv2026

Event-by-event track imaging of charged particles with an ultrafast plenoptic camera

Modern elementary particle detectors often require high-resolution three-dimensional particle tracking in large dense active volumes, which is difficult to achieve in standard devices without an extremely fine segmentation. In recent work, a plenoptic camera instrumented with a single-photon avalanche-diode array, called PLATON, demonstrated to image individual visible photons generated in monolithic scintillating material and reconstruct their three-dimensional origin from a single-event exposure, opening a route to high-spatial-resolution detection of elementary particles in unsegmented scintillator. However, those tests aimed to address photon sources of essentially zero geometric extent. In this work we close the gap to the tracking regime. First, we calibrated the PLATON prototype using light tracks in an organic plastic scintillator induced by a femtosecond infrared laser via two-photon absorption and characterised its capability to reconstruct photon-starved 3D lines with a novel algorithm, achieving good agreement with custom Monte Carlo simulation. Finally, the PLATON prototype was exposed to a test beam of pions at the CERN Proton Synchrotron. For the first time, a plenoptic detector system was successfully used to detect and reconstruct the 3D tracks of elementary particles from 2D photon-starved images on an event-by-event basis marking a transformative approach to high-resolution measurements.

physics.ins-det↗

arXiv2026

Magnetic Lifting of BIC Symmetry Protection Enables Nonreciprocal Beam Steering and Angular Information Encoding

Symmetry-protected bound states in the continuum (SP-BICs) offer exceptional optical confinement but remain nonradiative. Here, we demonstrate that magnetically lifting their protecting symmetry enables nonreciprocal beam steering with intrinsic angular information encoding. In a magneto-optical photonic crystal slab, an in-plane magnetic field converts an SP-BIC into a radiative quasi-BIC and, together with vertical dielectric asymmetry, continuously displaces the associated band extremum away from the Gamma point. The steered beam exhibits two independent locking relations: its wavelength is locked to the elevation angle, while its polarization orientation is locked to the azimuthal angle. These relations embed complementary spectral and polarization information into the scanning beam, providing additional sensing channels for multidimensional LiDAR. Moreover, the nonreciprocal dispersion gives different resonance frequencies at opposite wave vectors, supporting resonant emission at +k while back-reflected light at the same frequency is off resonance at -k, opening a route to intrinsic self-isolation and reduced optical feedback. These findings establish a unified framework connecting magnetic beam steering, angular information encoding, and nonreciprocal feedback suppression, with prospects for compact reconfigurable light sources and integrated optical engines.

physics.optics↗

arXiv2026

High Frame-Rate Mid-Infrared SPAD Camera

Single-photon avalanche diode (SPAD) arrays have transformed optical imaging by enabling photon-counting sensitivity, picosecond resolution, and high frame-rate operation. These capabilities, however, have remained confined to the visible and near-infrared, leaving the mid-infrared, the spectral region hosting the fundamental vibrational signatures of most molecules, largely inaccessible. Here, we demonstrate the first mid-IR SPAD camera by integrating broadband adiabatic frequency upconversion with a 512x512 Silicon SPAD array. This architecture transfers full SPAD functionality to the mid-IR, enabling room-temperature, low-noise, broadband photon-counting imaging. We achieve spectrally resolved mid-IR imaging at frame rates of up to 60,000 frames per second and capture nanosecond-scale laser-induced thermal dynamics via weak mid-IR blackbody emission, revealing spatial-temporal behavior inaccessible to existing technologies. These results establish a scalable platform for photon-resolved, ultrafast thermal and chemical imaging in a spectral range previously inaccessible to high-speed low-light detection.

physics.optics↗

arXiv2026

Hanbury Brown-Twiss interference with massively parallel spectral multiplexing for broadband light

Two-photon interference is a fundamental resource for quantum technologies and optical quantum computing, underpinning precision measurements, scalable entanglement distribution, and the operation of photonic circuits and quantum network protocols. Here, we report the first demonstration of massively parallel, wavelength-resolved photon bunching, revealing Hanbury Brown-Twiss correlations across 100 independent spectral channels. These observations are enabled by a fast, data-driven single-photon spectrometer that achieves 40 pm spectral and 40 ps temporal resolution over a 10 nm bandwidth, providing simultaneous access to spectro-temporal photon correlations without the need for narrowband filtering. This approach preserves photon flux while enabling high-dimensional quantum interference measurements across a broad spectrum. Our results establish frequency-multiplexed two-photon interference as a scalable and throughput-efficient platform for quantum-enhanced photonic technologies, offering a practical route toward room-temperature architectures that overcome loss limitations and advance the scalability for a variety of applications.

quant-ph↗

arXiv2026

A 320x240 SPAD dToF Flash LiDAR sensor combining TDC and multi-time-gating, achieving 108m range for LiDAR and AR/VR applications

We propose a joint TDC and multi-time-gated imaging single-photon avalanche diode LiDAR sensor featuring a maximum detection range of 108m with a minimum depth resolution (least significant bit) of 2.93mm, fabricated in 110nm CMOS technology. The sensor is implemented 320x240 pixels with a pitch of 23μm, achieving a maximum fill factor of 10% and a total size of 8.2mmx6.3mm. The power consumption of the pixel array is 167.4mW. Under a repetition rate of 3.125MHz, a laser power of 11.3mW, and a wavelength of 780nm, the sensor is designed to operate at up to 100klx background illumination with a centimetric depth precision. It can be further improved to 130klx by reducing image resolution to 160x120 pixels. In addition, the sensor can reconfigure the idle TSPCs integrated in the cluster into counters for histogramming, thereby reducing the size of the data processing module.

physics.optics↗

arXiv2026

An ultrafast plenoptic-camera system for high-resolution 3D particle tracking in unsegmented scintillators

Neutrino detectors, particle calorimeters and some dark matter detectors require dense and massive active materials. An extremely fine segmentation is desirable to achieve precise three-dimensional particle tracking. However, such systems introduce significant challenges in construction and demand a large number of readout electronics channels, leading to extremely high costs. In this article, we propose an alternative approach to elementary particle detection that enables ultrafast three-dimensional high-resolution imaging in large volumes of unsegmented scintillator. Enabling technologies are plenoptic systems and time-resolving single-photon avalanche diode array imaging sensors. Together, they enabled us, using a plenoptic camera, to reconstruct the origin of single photons in the scintillator. A case study focused on neutrino detection demonstrates full event reconstruction with a spatial resolution of two hundred micrometres. This work paves the way for a class of particle detectors whose capabilities should be further enhanced through future developments and expanded to Cherenkov light detection, medical imaging and neutron detection.

physics.ins-det↗

arXiv2026

Probing Stellar Kinematics with the Time-Asymmetric Hanbury Brown and Twiss Effect

Intensity interferometry (II) offers a powerful means to observe stellar objects with a high resolution. In this work, we demonstrate that II can also probe internal stellar kinematics by revealing a time-asymmetric Hanbury Brown and Twiss (HBT) effect, causing a measurable shift in the temporal correlation peak away from zero delay. We develop numerical models to simulate this effect for two distinct astrophysical scenarios: an emission-line circumstellar disk and an absorption-line binary system. Our simulations reveal a clear sensitivity of this temporal asymmetry to the system's inclination angle, velocity symmetry, and internal dynamics. This suggests that, with sufficiently high time resolution, II can be used to extract quantitative information about internal kinematics, offering a new observational window on stellar dynamics.

astro-ph.IM↗

arXiv2026

28 GHz Wireless Channel Characterization for a Quantum Computer Cryostat at 4 Kelvin

The scalability of quantum computing systems is constrained by the wiring complexity and thermal load introduced by dense wiring for control, readout and synchronization at cryogenic temperatures. To address this challenge, we explore the feasibility of wireless communication within a cryostat for a multi-core quantum computer, focusing on wireless channel characterization at cryogenic temperatures. We propose to place on-chip differential dipole antennas within the cryostat, designed to operate at 28 GHz in temperatures as low as 4 K. We model the antennas inside a realistic cryostat and, using full-wave electromagnetic simulations, we analyze impedance matching, spatial field distribution, and energy reverberation due to metallic structures. The wireless channel is characterized through measured channel impulse response (CIR) across multiple receiver antenna positions. The results demonstrate potential for reliable shortrange communication with high Signal-to-Noise Ratio (SNR) and limited sensitivity to positional variation, at the cost of nonnegligible delay spread, due to significant multipath effects.

quant-ph↗

arXiv2025

Enabling Technologies for Scalable Superconducting Quantum Computing

Experiments with superconducting quantum processors have successfully demonstrated the basic functions needed for quantum computation and evidence of utility, albeit without a sizable array of error-corrected qubits. The realization of the full potential of quantum computing centers on achieving large scale fault-tolerant quantum computers. Science, engineering and industry advances are needed to robustly generate, sustain, and efficiently manipulate an exponentially large computational (Hilbert) space as well as supply the number and quality components needed for such a scaled system. In this article, we suggest critical areas of quantum system and ecosystem development, with respect to the handling and transmission of quantum information within and out of a cryogenic environment, that would accelerate the development of quantum computers based on superconducting circuits.

quant-ph↗

arXiv2025

Lattice Surgery Aware Resource Analysis for the Mapping and Scheduling of Quantum Circuits for Scalable Modular Architectures

Quantum computing platforms are evolving to a point where placing high numbers of qubits into a single core comes with certain difficulties such as fidelity, crosstalk, and high power consumption of dense classical electronics. Utilizing distributed cores, each hosting logical data qubits and logical ancillas connected via classical and quantum communication channels, offers a promising alternative. However, building such a system for logical qubits requires additional optimizations, such as minimizing the amount of state transfer between cores for inter-core two-qubit gates and optimizing the routing of magic states distilled in a magic state factory. In this work, we investigate such a system and its statistics in terms of classical and quantum resources. First, we restrict our quantum gate set to a universal gate set consisting of CNOT, H, T, S, and Pauli gates. We then developed a framework that can take any quantum circuit, transpile it to our gate set using Qiskit, and then partition the qubits using the KaHIP graph partitioner to balanced partitions. Afterwards, we built an algorithm to map these graphs onto the 2D mesh of quantum cores by converting the problem into a Quadratic Assignment Problem with Fixed Assignment (QAPFA) to minimize the routing of leftover two-qubit gates between cores and the total travel of magic states from the magic state factory. Following this stage, the gates are scheduled using an algorithm that takes care of the timing of the gate set. As a final stage, our framework reports detailed statistics such as the number of classical communications, the number of EPR pairs and magic states consumed, and timing overheads for pre- and post- processing for inter-core state transfers. These results help to quantify both classical and quantum resources that are used in distributed logical quantum computing architectures.

quant-ph↗

arXiv2025

Reconfigurable, large-format D-ToF/photon-counting SPAD image sensors with embedded FPGA for scene adaptability

CMOS-compatible single-photon avalanche diodes (SPADs) have emerged in many systems as the solution of choice for cameras with photon-number resolution and photon counting capabilities. Being natively digital optical interfaces, SPADs are naturally drawn to in situ logic processing and event-driven computation; they are usually coupled to discrete FPGAs to enable reconfigurability. In this work, we propose to bring the FPGA on-chip, in direct contact with the SPADs at pixel or cluster level. To demonstrate the suitability of this approach, we created an architecture for processing timestamps and photon counts using programmable weighted sums based on an efficient use of look-up tables. The outputs are processed hierarchically, similarly to what is done in FPGAs, reducing power consumption and simplifying I/Os. Finally, we show how artificial neural networks can be designed and reprogrammed by using look-up tables in an efficient way.

eess.IV↗

arXiv2025

Systematic validation of time-resolved diffuse optical simulators via non-contact SPAD-based measurements

Objective: Time-domain diffuse optical imaging (DOI) requires accurate forward models for photon propagation in scattering media. However, existing simulators lack comprehensive experimental validation, especially for non-contact configurations with oblique illumination. This study rigorously evaluates three widely used open-source simulators, including MMC, NIRFASTer, and Toast++, using time-resolved experimental data. Approach: All simulations employed a unified mesh and point-source illumination. Virtual source correction was applied to FEM solvers for oblique incidence. A time-resolved DOI system with a 32 $\times$ 32 single-photon avalanche diode (SPAD) array acquired transmission-mode data from 16 standardized phantoms with varying absorption coefficient $μ_a$ and reduced scattering coefficient $μ_s'$. The simulation results were quantified across five metrics: spatial-domain (SD) precision, time-domain (TD) precision, oblique beam accuracy, computational speed, and mesh-density independence. Results: Among three simulators, MMC achieves superior accuracy in SD and TD metrics, and shows robustness across all optical properties. NIRFASTer and Toast++ demonstrate comparable overall performance. In general, MMC is optimal for accuracy-critical TD-DOI applications, while NIRFASTer and Toast++ suit scenarios prioritizing speed with sufficiently large $μ_s'$. Besides, virtual source correction is essential for non-contact FEM modeling, which reduced average errors by > 34% in large-angle scenarios. Significance: This work provides benchmarked guidelines for simulator selection during the development phase of next-generation TD-DOI systems. Our work represents the first study to systematically validate TD simulators against SPAD array-based data under clinically relevant non-contact conditions, bridging a critical gap in biomedical optical simulation standards.

physics.optics↗

arXiv2025

Power Delivery for Cryogenic Scalable Quantum Applications: Challenges and Opportunities

Quantum technologies offer unprecedented capabilities in computation and secure information transfer. Their implementation requires qubits to operate at cryogenic temperatures (CT) while control and readout electronics typically still remains at room temperature (RT). As systems scale to millions of qubits, the electronics should also operate at CT to avoid a wiring bottleneck. However, wired power transfer from RT for such electronics introduces severe challenges, including thermal load between cooling stages, Joule heating, noise coupling, and wiring scalability. This paper addresses those challenges by evaluating several candidate architectures for scalable power transfer in the dilution frige: high-voltage (HV) wired power transfer, radiative wireless transfer, non-radiative wireless transfer, and a hybrid HV and non-radiative transfer. These architectures are analyzed in terms of thermal load, power loss, heating, coupling noise, power density, scalability, reliability, and complexity. Comparative analysis demonstrates the trade-offs among these architectures, while highlighting HV non-radiative transfer as a promising candidate for scalable quantum systems.

eess.SY↗

arXiv2025

PlatonSPAD: A novel SPAD sensor for large-scale high-resolution particle detectors

High-resolution 3D tracking with sub-nanosecond timing is required for the detection of elementary particles, such as neutrinos. Conventional detectors, which utilize analog silicon photomultipliers, face challenges in balancing spatial resolution and scalability. To address this issue, a CMOS single-photon avalanche diode (SPAD)-based high-resolution particle detector is being developed. This work presents a study on SPAD layout optimization and a 4x4 SPAD macropixel module, fabricated in 110 nm CIS technology. Measurement results confirm that high-fill-factor designs improve photon detection efficiency without significant noise degradation. Furthermore, event-driven photon mapping and time stamping, enabled by time-to-digital converters and dedicated pixel circuits integrated into the 4x4 SPAD macropixel, were successfully demonstrated. This work is an essential step towards a sensor that detects probabilistic particle interactions and it lays the groundwork for the development of future large-scale SPAD-based particle detectors.

physics.ins-det↗

arXiv2025

Transporter: A 128$\times$4 SPAD Imager with On-chip Encoder for Spiking Neural Network-based Processing

Single-photon avalanche diodes (SPADs) are widely used today in time-resolved imaging applications. However, traditional architectures rely on time-to-digital converters (TDCs) and histogram-based processing, leading to significant data transfer and processing challenges. Previous work based on recurrent neural networks has realized histogram-free processing. To further address these limitations, we propose a novel paradigm that eliminates TDCs by integrating in-sensor spike encoders. This approach enables preprocessing of photon arrival events in the sensor while significantly compressing data, reducing complexity, and maintaining real-time edge processing capabilities. A dedicated spike encoder folds multiple laser repetition periods, transforming phase-based spike trains into density-based spike trains optimized for spiking neural network processing and training via backpropagation through time. As a proof of concept, we introduce Transporter, a 128$\times$4 SPAD sensor with a per-pixel D flip-flop ring-based spike encoder, designed for intelligent active time-resolved imaging. This work demonstrates a path toward more efficient, neuromorphic SPAD imaging systems with reduced data overhead and enhanced real-time processing.

eess.IV↗

arXiv2025

Further Characterisation of Digital Pixel Test Structures Implemented in a 65 nm CMOS Process

The next generation of MAPS for future tracking detectors will have to meet stringent requirements placed on them. One such detector is the ALICE ITS3 that aims to be very light at 0.07% X/X$_{0}$ per layer and have a low power consumption in the active area of 40 mW/cm$^{2}$ by implementing wafer-scale MAPS bent into cylindrical half layers. To address these challenging requirements, the ALICE ITS3 project, in conjunction with the CERN EP R&D on monolithic pixel sensors, proposed the Tower Partners Semiconductor Co. 65 nm CMOS process as the starting point for the sensor. After the initial results confirmed the detection efficiency and radiation hardness, the choice of the technology was solidified by demonstrating the feasibility of operating MAPS in low-power consumption regimes, < 50 mW/cm$^{2}$, while maintaining high-quality performance. This was shown through a detailed characterisation of the Digital Pixel Test Structure (DPTS) prototype exposed to X-rays and ionising beams, and the results are presented in this article. Additionally, the sensor was further investigated through studies of the fake-hit rate, the linearity of the front-end in the range 1.7-28 keV, the performance after ionising irradiation, and the detection efficiency of inclined tracks in the range 0-45$^\circ$.

physics.ins-det↗

arXiv2025

On the Impact of Classical and Quantum Communication Networks Upon Modular Quantum Computing Architecture System Performance

Modular architectures are a promising approach to scaling quantum computers beyond the limits of monolithic designs. However, non-local communications between different quantum processors might significantly impact overall system performance. In this work, we investigate the role of the network infrastructure in modular quantum computing architectures, focusing on coherence loss due to communication constraints. We analyze the impact of classical network latency on quantum teleportation and identify conditions under which it becomes a bottleneck. Additionally, we study different network topologies and assess how communication resources affect the number and parallelization of inter-core communications. Finally, we conduct a full-stack evaluation of the architecture under varying communication parameters, demonstrating how these factors influence the overall system performance. The results show that classical communication does not become a bottleneck for systems exceeding one million qubits, given current technology assumptions, even with modest clock frequencies and parallel wired interconnects. Additionally, increasing quantum communication resources generally shortens execution time, although it may introduce additional communication overhead. The optimal number of quantum links between QCores depends on both the algorithm being executed and the chosen inter-core topology. Our findings offer valuable guidance for designing modular architectures, enabling scalable quantum computing.

quant-ph↗

arXiv2025

Event Cameras Meet SPADs for High-Speed, Low-Bandwidth Imaging

Traditional cameras face a trade-off between low-light performance and high-speed imaging: longer exposure times to capture sufficient light results in motion blur, whereas shorter exposures result in Poisson-corrupted noisy images. While burst photography techniques help mitigate this tradeoff, conventional cameras are fundamentally limited in their sensor noise characteristics. Event cameras and single-photon avalanche diode (SPAD) sensors have emerged as promising alternatives to conventional cameras due to their desirable properties. SPADs are capable of single-photon sensitivity with microsecond temporal resolution, and event cameras can measure brightness changes up to 1 MHz with low bandwidth requirements. We show that these properties are complementary, and can help achieve low-light, high-speed image reconstruction with low bandwidth requirements. We introduce a sensor fusion framework to combine SPADs with event cameras to improves the reconstruction of high-speed, low-light scenes while reducing the high bandwidth cost associated with using every SPAD frame. Our evaluation, on both synthetic and real sensor data, demonstrates significant enhancements ( > 5 dB PSNR) in reconstructing low-light scenes at high temporal resolution (100 kHz) compared to conventional cameras. Event-SPAD fusion shows great promise for real-world applications, such as robotics or medical imaging.

eess.IV↗