arXiv subjects

Jerzy Szuniewicz

Publications and source records attributed to Jerzy Szuniewicz.

6 recordsLinked to original sources

arXiv2026

An Atomic Interface for High-Dimensional Temporal Mode Quantum Networks

Temporal modes of photons are a promising encoding scheme for high-dimensional quantum networks due to their high channel capacity and fiber compatibility. However, realizing their full potential requires devices capable of synchronizing, processing and interfacing these modes across photonic and atomic bandwidths. In this work, we demonstrate a programmable high-dimensional temporal mode processor using a Raman quantum memory in warm cesium vapor. We exploit the single-mode nature of the Raman interaction kernel, dynamically shaping the control field to synthesize a tunable coherent filter that selectively addresses specific temporal waveforms. This mechanism enables on-demand storage, filtering, and conversion, providing a coherent interface between MHz- and GHz-bandwidth modes. We validate the platform's selectivity across a basis of 30 orthogonal Hermite-Gaussian modes and certify high-fidelity quantum operation via 5-dimensional process tomography. By combining deterministic mode conversion with bidirectional bandwidth interfacing, we establish the Raman memory as a critical active node for scalable quantum information processing.

quant-ph↗

arXiv2026

Quantum interference between spectral bandwidth mismatched photons

Two-photon interference is a cornerstone of photonic quantum technologies. However, its practical implementation in promising hybrid architectures is severely constrained by the requirement of photon wavepacket indistinguishability, in particular, in terms of the photon linewidth and associated time scale. While narrowband filtering can improve interference visibility, it introduces significant photon loss - a critical limitation for applications. Here, we experimentally demonstrate an efficient approach to enable non-classical two-photon interference between spectral-bandwidth mismatched photons using an electro-optic time lens. We increase the visibility of Hong-Ou-Mandel interference between photons of 10-fold spectral bandwidth mismatch by more than 12 times, achieving non-classical two-photon interference visibility without spectral filtering. This result opens the possibility to efficiently integrate quantum systems operating at different time scales for hybrid quantum communication, teleportation, entanglement swapping, distributed sensing, and hybrid quantum computing.

quant-ph↗

arXiv2025

Enhancing Quantum Memories with Light-Matter Interference

Future optical quantum technologies, such as quantum networks, distributed quantum computing and sensing, demand efficient, broadband quantum memories. However, achieving high efficiency without introducing noise, reducing bandwidth, or limiting scalability remains a challenge. Here, we present a new approach to enhance quantum memory protocols by leveraging constructive light-matter interference, leading to an increase in memory efficiency without increasing atomic density or laser intensity. We implement this method in a Raman quantum memory in warm Cesium vapor, and achieve more than a three-fold improvement in total efficiency reaching $(34.3\pm8.4)\%$, while retaining GHz-bandwidth operation and low noise levels. Numerical simulations predict that this approach can boost efficiencies in systems limited by atomic density, such as cold atomic ensembles, from $65\%$ to beyond $96\%$, while in warm atomic vapors it could reduce the laser intensity needed to reach a given efficiency by over an order-of-magnitude, exceeding $95\%$ total efficiency. Furthermore, our method preserves the single-mode nature of the memory at high efficiencies. This new protocol is applicable to various memory architectures, paving the way toward scalable, efficient, low-noise, and high-bandwidth quantum memories.

quant-ph↗

arXiv2023

High-dimensional quantum correlation measurements with an adaptively gated hybrid single-photon camera

Efficient measurement of high-dimensional quantum correlations, especially spatial ones, is essential for quantum technologies, given their inherent high dimensionality and easy manipulation with basic optical elements. We propose and demonstrate an adaptively-gated hybrid intensified camera (HIC) that combines the information from a high spatial resolution sensor and a high temporal resolution detector, offering precise control over the number of photons detected within each frame. The HIC facilitates spatially resolved single-photon counting measurements. We study the measurement of momentum correlations of photon pairs generated in type-I spontaneous parametric down-conversion with the HIC and demonstrate the possibility of time-tagging the registered photons. With a spatial resolution of nearly 9 megapixels and nanosecond temporal resolution, this system allows for the realization of previously infeasible quantum optics experiments.

quant-ph↗

arXiv2023

Noise Resistant Phase Imaging with Intensity Correlation

Interferometric methods, renowned for their reliability and precision, play a vital role in phase imaging. Interferometry typically requires high coherence and stability between the measured and the reference beam. The presence of rapid phase fluctuations averages out the interferogram, erasing the spatial phase information. This difficulty can be circumvented by shortening the measurement time. However, shortening the measurement time results in smaller photon counting rates precluding its applicability to low-intensity phase imaging. We introduce and experimentally demonstrate a phase imaging technique that is immune to position-independent, time-dependent phase fluctuation. We accomplish this by measuring intensity correlation instead of intensity. Our method enables using long measurement times and is therefore advantageous when the photon flux is very low. We use a Fisher information-based approach to show that the precision of phase reconstruction achieved using our method is in fact the best achievable precision in the scenario when two photons are detected per phase stability time.

physics.optics↗

arXiv2021

Self-referenced hologram of a single photon beam

Quantitative characterization of the spatial structure of single photons is essential for free-space quantum communication and quantum imaging. We introduce an interferometric technique that enables the complete characterization of a two-dimensional probability amplitude of a single photon. Importantly, in contrast to methods that use a reference photon for the phase measurement, our technique relies on a single photon interfering with itself. Our setup comprises of a heralded single-photon source with an unknown spatial phase and a modified Mach-Zehnder interferometer with a spatial filter in one of its arms. The spatial filter removes the unknown spatial phase and the filtered beam interferes with the unaltered beam passing through the other arm of the interferometer. We experimentally confirm the feasibility of our technique by reconstructing the spatial phase of heralded single photons using the lowest order interference fringes. This technique can be applied to the characterization of arbitrary pure spatial states of single photons.

quant-ph↗