arXiv subjects

Ilse Maillette de Buy Wenniger

Publications and source records attributed to Ilse Maillette de Buy Wenniger.

8 recordsLinked to original sources

arXiv2026

Super-resolving frequency measurement with mode-selective quantum memory

High-precision optical frequency measurement underpins modern science and technology, yet conventional spectroscopic techniques struggle to resolve sub-linewidth spectral features. Here, we introduce a platform for super-resolved frequency estimation based on a mode-selective atomic Raman quantum memory implemented in warm caesium vapour. By precisely engineering the light-matter interaction, the memory coherently stores the optimal temporal mode with high fidelity and retrieves it on demand, achieving mode crosstalk as low as 0.34%. To estimate the separation between two spectral lines, we experimentally measure the mean squared error of the frequency estimate, reaching a sensitivity of 1/20 of the linewidth and a ($34\pm4$)-fold enhancement in precision over direct intensity measurements. This enhanced frequency resolution, combined with on-demand storage, retrieval, and mode-conversion capabilities, establishes a pathway toward multifunctional memory-based time-frequency sensors and their integration within quantum networks.

quant-ph↗

arXiv2026

Dynamic rephasing in a telecom warm vapor quantum memory

The Off-Resonant Cascaded Absorption (ORCA) protocol in warm atomic vapors offers a scalable platform for high-bandwidth, low noise quantum memories, but its coherence time is fundamentally limited by Doppler-induced dephasing. We introduce and experimentally demonstrate a dynamic rephasing protocol that counteracts Doppler dephasing in a telecom-band ORCA quantum memory. By transferring the stored excitation to an auxiliary shelving state, we effectively reverse the accumulated Doppler phase and extend the storage time by a factor of 50 while preserving the memory's GHz bandwidth and low noise. Using this protocol, we then demonstrate on-demand storage and retrieval of four independent time-bin modes within a single warm vapor memory -- showing that Doppler dephasing can alternatively be harnessed for high-dimensional temporal mode processing. Our results establish rephasing in warm atomic vapors as a viable route toward high-bandwidth, temporally multiplexed quantum memories operating at room temperature.

quant-ph↗

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↗

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↗

arXiv2025

Optimizing the quantum interference between single photons and local oscillator with photon correlations

The quantum interference between a coherent state and a single photon is an important tool in continuous variable optical quantum technologies to characterize and engineer non-Gaussian quantum states. Semiconductor quantum dots, which have recently emerged as a key platform for efficient single-photon generation, could become interesting assets in this context. An essential parameter for interfering single photons and classical fields is the mean wavepacket overlap between both fields. Here, we report on two homodyne photon-correlation techniques enabling the precise measurement of the overlap between a single photon generated by a quantum dot-cavity device and pulsed laser light. The different statistics of interfering fields lead to specific signatures of the quantum interference on the photon correlations at the output of the interfering beam splitter. We compare the behavior of maximized overlap, measuring either the Hong-Ou-Mandel visibility between both outputs or the photon bunching at a single output. Through careful tailoring of the laser light in various degrees of freedom, we maximize the overlap to $76\,\%$, with limitations primarily due to mismatched spectral and temporal profiles and low-frequency charge noise in the single-photon source.

quant-ph↗

arXiv2024

Indistinguishability of remote quantum dot-cavity single-photon sources

Generating identical photons from remote emitter-based bright single-photon sources is an important step for scaling up optical quantum technologies. Here, we study the Hong-Ou-Mandel interference of photons emitted from remote sources based on semiconductor quantum dots. We make use of a deterministic fabrication technique to position the quantum dots in a spectrally resonant micropillar cavity and fine tune their operation wavelength electrically. Doing so, we can match four pairs of sources between five distinct sources, study them under various excitation schemes and measure their degree of indistinguishability. We demonstrate remote indistinguishabiltiy between 44$\pm$1% and 69$\pm$1% depending on the pair of sources and excitation conditions, record values for quantum dots in cavities. The relative contribution of pure dephasing and spectral diffusion is then analysed, revealing that the remaining distinguishability is mostly due to low frequency noise

quant-ph↗

arXiv2021

Intermittency of CsPbBr$_3$ perovskite quantum dots analyzed by an unbiased statistical analysis

We analyze intermittency in intensity and fluorescence lifetime of CsPbBr$_3$ perovskite quantum dots by applying unbiased Bayesian inference analysis methods. We apply changepoint analysis (CPA) and a Bayesian state clustering algorithm to determine the timing of switching events and the number of states between which switching occurs in a statistically unbiased manner, which we have benchmarked particularly to apply to highly multistate emitters. We conclude that perovskite quantum dots display a plethora of gray states in which brightness broadly speaking correlates inversely with decay rate, confirming the multiple recombination centers model. We leverage the CPA partitioning analysis to examine aging and memory effects. We find that dots tend to return to the bright state before jumping to a dim state, and that when choosing a dim state they tend to explore the entire set of states available.

cond-mat.mes-hall↗

arXiv2019

Reproducibility of high-performance quantum dot single-photon sources

Single-photon sources based on semiconductor quantum dots have emerged as an excellent platform for high efficiency quantum light generation. However, scalability remains a challenge since quantum dots generally present inhomogeneous characteristics. Here we benchmark the performance of fifteen deterministically fabricated single-photon sources. They display an average indistinguishability of 90.6 +/- 2.8 % with a single-photon purity of 95.4 +/- 1.5 % and high homogeneity in operation wavelength and temporal profile. Each source also has state-of-the-art brightness with an average first lens brightness value of 13.6 +/- 4.4 %. Whilst the highest brightness is obtained with a charged quantum dot, the highest quantum purity is obtained with neutral ones. We also introduce various techniques to identify the nature of the emitting state. Our study sets the groundwork for large-scale fabrication of identical sources by identifying the remaining challenges and outlining solutions.

quant-ph↗