arXiv subjects

Michał Parniak

Publications and source records attributed to Michał Parniak.

At least 19 recordsLinked to original sources

arXiv2026

Measuring Interaction-Induced Energy Shifts of Rydberg Atoms in Hot Vapor

We demonstrate a method to measure energy shifts of the top level in a four-level ladder setup induced by atom interactions in thermal vapors. It utilizes the observation of two transmission minima corresponding to a split electromagnetically induced absorption (EIA) effect. We apply this method to measure mean Rydberg atom interactions in a hot vapor. We believe this approach could provide a valuable tool for accurately modeling mean-field Rydberg atom interactions, as well as sensing the occurrence of strong interactions.

physics.atom-ph↗

arXiv2026

Multiplexed storage and interaction of Rydberg spinwaves via the gradient echo memory protocol

Collective Rydberg excitations offer strong and controllable interactions for quantum information processing, sensing, and nonlinear quantum optics, but their integration with temporally or spectrally multiplexed schemes, such as the Gradient Echo Memory (GEM) protocol, is hindered by rapid motional dephasing caused by the large spinwave wavevector. We demonstrate a new type of multi-photon addressing and interfacing scheme (with levels following the shape of the letter Ń) that allows us to generate collective Rydberg excitations with near-zero momentum transfer, extending the Rydberg spinwave lifetime almost tenfold. The scheme relies on two additional off-resonant driving fields arranged at a magic angle, forming a closed wavevector loop while remaining compatible with GEM-induced inhomogeneous broadening. This enables storage and manipulation of long-lived Rydberg spinwaves in a multimode quantum memory. Using microwave coupling between neighboring Rydberg states, we can control the attenuation between stored excitation modes by interaction-induced decay and demonstrate interaction-controlled diffraction of a retrieved optical signal. Our results reestablish compatibility between Rydberg excitations and GEM, providing a route toward multimode quantum memories with controllable long-range interactions and applications in quantum networking, sensing, and quantum information processing.

quant-ph↗

arXiv2026

Background-free calibrated electric-field imaging with Rydberg-state fluorescence and Autler-Townes splitting

We demonstrate a spatially resolved method for imaging millimeter-wave (mmWave) electric fields using Rydberg-state fluorescence in a warm atomic vapor. By utilizing a multi-photon ladder excitation scheme, we leverage a specific decay channel that remains dark in the absence of the mmWave field, resulting in high-contrast imaging with effectively zero background. Absolute calibration of the local electric field is achieved by reconstructing the Autler-Townes splitting of the Rydberg resonance across the imaging volume. To ensure robust field extraction across a wide dynamic range--including regimes where spectral features are not fully resolved--we employ a steady-state analysis based on the Gorini-Kossakowski-Sudarshan-Lindblad (GKSL) master equation. We apply this technique to visualize standing-wave interference patterns within a vapor cell and demonstrate the ability to engineer local field distributions using structured dielectric reflectors. This approach provides a versatile and self-calibrating platform for the diagnostic imaging of high-frequency electromagnetic fields and the characterization of mmWave-optical interfaces.

physics.atom-ph↗

arXiv2026

Hybrid quantum memory leveraging slow-light and gradient-echo duality

We demonstrate a hybrid quantum memory that combines Gradient Echo Memory (GEM) and Electromagnetically Induced Transparency (EIT) protocols for reversible mapping between light and atomic coherence. By leveraging GEM and EIT complementarity, we realize time-to-frequency and frequency-to-time conversion mechanisms for spectro-temporal modes. This capability provides a versatile tool for quantum communication, where coherent frequency-time conversion enhances network interoperability. In addition, the protocol may enable fundamental studies of atomic coherence, including investigations of Rydberg polaritons and mapping of single Rydberg excitations and ionic impurities.

quant-ph↗

arXiv2026

Coherent terahertz field tomographic imaging in warm Rydberg vapors

Rydberg atom-based sensors have emerged as highly sensitive tools for terahertz (THz) metrology, yet most current imaging techniques discard crucial phase information. In this Letter, we present a coherent THz-to-optical conversion scheme in warm Rb vapor that enables complex-amplitude field imaging. By manipulating the phase-matching conditions via an adjustable interference pattern of optical probe beams, we demonstrate the ability to perform tomographic reconstruction of the THz field distribution. We experimentally validate the spatial resolution and phase-sensitivity of the system by resolving sub-centimeter features and identifying incident angles of arrival. Our results establish a robust framework for phase-resolved THz imaging and holography using atomic vapors at room temperature.

physics.atom-ph↗

arXiv2026

Rydberg Receivers for Space Applications

Rydberg-atom sensors convert radiofrequency, microwave and terahertz fields into optical signals with SI-traceable calibration, high sensitivity, and broad tunability. This review assesses their potential for space applications by comparing five general architectures (Autler-Townes, AC-Stark, superheterodyne, radiofrequency-to-optical conversion, and fluorescence) against space application needs. We identify promising roles in radiometry, radar, terahertz sensing, and in-orbit calibration, and outline key limitations, including shot noise, sparse terahertz transitions, and currently large Size, Weight, Power and Cost. A staged roadmap highlights which uncertainties should be resolved first and how research organisations, industry and space agencies could take the lead for the different aspects.

quant-ph↗

arXiv2025

Microwave-field quantum metrology with inherent robustness against detection losses enabled by Rydberg interactions

Quantum sensing and metrology present one of the most promising near-term applications in the field of quantum technologies, with quantum sensors enabling unprecedented precision in measurements of electric, magnetic or gravitational fields and displacements. Experimental loss at the detection stage remains one of the key obstacles to achieving a truly quantum advantage in many practical scenarios. Here, we combine the capabilities of Rydberg atoms to both sense external fields and be used for quantum information processing, thereby largely overcoming the issue of detection losses. While utilising the large dipole moments of Rydberg atoms in an ensemble to achieve a $\SI{39}{\nV\per\cm \hertz\tothe{-1/2}}$ sensitivity, we employ inter-atomic dipolar interactions to take advantage of an error-prevention protocol that protects information against conventional losses at the detection stage. Counterintuitively, the protocol's idea is based on introducing an additional non-linear, lossy quantum channel, which results in a 3.3-fold enhancement of Fisher information. The presented results pave the way for broader adoption of quantum-information-inspired enhancements enabled by intrinsic interactions present in a sensor system, and more broadly in practical quantum metrology and communication, without the need for a general-purpose quantum computer.

quant-ph↗

arXiv2025

Electric-field metrology of a terahertz frequency comb using Rydberg atoms

Terahertz radiation finds an increasing number of applications, yet efficient generation and detection remain a challenge and an active area of research. In particular, the precise detection of weak and narrowband terahertz signals is notoriously difficult. Here, we employ a novel type of single-photon detector based on Rydberg atoms to both detect and calibrate a terahertz frequency comb over an octave-spanning range, yet with a MHz-level selectivity. We calibrate the intensity of the electric field of the comb against the fundamental atomic properties, while achieving the intensity (power) sensitivity down to 45.2 $\mathrm{fW\ cm^{-2}\ Hz^{-0.5}}$ (1.84 $\mathrm{fW\ Hz^{-0.5}}$) within a single mode of the frequency comb, all in a room-temperature operated setup. Our results elucidate the transition of terahertz frequency combs into the quantum regime, enabling high-precision and high-sensitivity spectroscopy. This breakthrough allows terahertz science to better leverage revolutionary techniques developed for optical frequency combs.

physics.optics↗

arXiv2025

Superheterodyne Rydberg S-band receiver with a multi-tone local oscillator based on an atomic transition loop

Atomic-vapor sensors based on Rydberg atoms now face a transition towards practical applications, with several outstanding challenges. To achieve the best sensitivities, a superheterodyne mode of operation is desired, which requires the presence of a local oscillator in the vapor cell. This local oscillator hinders several advantages of the sensor, such as stealthy and all-optical operation. We propose and realize a detection scheme, which avoids some of those problems by using multi-tone mixing, where direct usage of the local oscillator at the same frequency is not required. Our scheme is further elaborated on using efficient theoretical methods to predict the performance of the sensor. Our sensor operates at the S-band frequency, known for its usage in IEEE 802.11 (Wi-Fi) networks, without interfering with the signal itself.

physics.optics↗

arXiv2025

Optically-biased Rydberg microwave receiver enabled by hybrid nonlinear interferometry

The coupling of Rydberg vapour medium to both microwave and optical fields allows harnessing the merits of all-optical detection, e.g. weak disruption of the measured field and invulnerability to extremely strong fields, owing to the lack of a conventional antenna in the detector. However, the highest sensitivity in this approach is typically achieved by introducing an additional microwave field acting as a local oscillator, thereby compromising the all-optical nature of the measurement. Here we propose an alternative method, optical-bias detection, that allows truly all-optical operation, while retaining exceptional sensitivity. We tackle the issue of laser phase noise, emerging in this type of detection, via a simultaneous measurement of the laser phase noise in a nonlinear process and real-time data processing, which overall yields an improvement of $35\ \mathrm{dB}$ in terms of signal-to-noise ratio compared with the basic approach. We report the sensitivity of $176\ \mathrm{nV/cm/\sqrt{Hz}}$ and reliable operation up to $3.5\ \mathrm{mV/cm}$ of $13.9\ \mathrm{GHz}$ electric field. We also demonstrate a quadrature-amplitude modulated data transmission, underlining the capability of the system to detect quadratures of the microwave field. This approach is thus directly comparable to the state-of-the-art superheterodyne, while retaining the merits of all-optical detection.

physics.atom-ph↗

arXiv2025

A warm Rydberg atom-based quadrature amplitude-modulated receiver

Rydberg atoms exhibit remarkable sensitivity to electromagnetic fields, making them promising candidates for revolutionizing field sensors. Unlike conventional antennas, they neither disturb the measured field nor necessitate intricate calibration procedures. In this study, we propose a protocol for signal reception near the 2.4 GHz Wi-Fi frequency band, harnessing the capabilities of warm Rydberg atoms. Our focus lies on exploring various quadrature amplitude modulations and transmission frequencies through heterodyne detection. We offer a comprehensive characterization of our setup, encompassing the atomic response frequency range and attainable electric field amplitudes. Additionally, we delve into analyzing communication errors using Voronoi diagrams, along with evaluating the communication channel capacity across different modulation schemes. Our findings not only lay the groundwork for future wireless communication applications, but also present opportunities to refine protocols in classical communication and field sensing domains.

physics.atom-ph↗

arXiv2025

Coherent optical two-photon resonance tomographic imaging in three dimensions

Magnetic resonance imaging is a three-dimensional imaging technique, where a gradient of the magnetic field is used to interrogate spin resonances with spatial resolution. The application of this technique to probe the coherence of atoms with good three-dimensional resolution is a challenging application. We propose and demonstrate an optical method to probe spin resonances via a two-photon Raman transition, reconstructing the 3D-structure of an atomic ensemble's coherence, which is itself subject to external fields. Our method relies on a single time-and-space resolved heterodyne measurement, allowing the reconstruction of a complex 3D coherence profile. Owing to the optical interface, we reach a tomographic image resolution of $14\times14\times36$ $μ\mathrm{m}^3$. The technique allows to probe any transparent medium with a resonance structure and provides a robust diagnostic tool for atom-based quantum information protocols. As such, it is a viable technique for application to magnetometry, electrometry, and imaging of electromagnetic fields.

quant-ph↗

arXiv2024

Atomic-optical interferometry in fractured loops: a general solution for Rydberg radio frequency receivers

The development of novel radio frequency atomic receivers brings attention to the theoretical description of atom-light interactions in sophisticated, multilevel schemes. Of special interest, are the schemes where several interaction paths interfere with each other, bringing about the phase-sensitive measurement of detected radio fields. In the theoretical modeling of those cases, the common assumptions are often insufficient to determine the boundary detection parameters, such as receiving bandwidth or saturation point, critical for practical considerations of atomic sensing technology. This evokes the resurfacing of a long-standing problem on how to describe an atom-light interaction in a fractured loop. In such a case, the quantum steady state is not achieved even with constant, continuous interactions. Here we propose a method for modeling of such a system, basing our approach on the Fourier expansion of a non-equilibrium steady state. The proposed solution is both numerically effective and able to predict edge cases, such as saturation. Furthermore, as an example, we employ this method to provide a complete description of a Rydberg superheterodyne receiver, obtaining the boundary parameters describing the operation of this atomic detector.

physics.atom-ph↗

arXiv2024

A Rydberg atom based system for benchmarking mmWave automotive radar chips

Rydberg atomic sensors and receivers have enabled sensitive and traceable measurements of RF fields at a wide range of frequencies. Here we demonstrate the detection of electric field amplitude in the extremely high frequency (EHF) band, at $131\ \mathrm{GHz}$. In our approach we propagate the EHF field in a beam, with control over its direction and polarization at the detector using photonic waveplates. This way, we take advantage of the highest detection sensitivity, registered for collinear propagation and circular polarization. To exhibit the potential for applications in this kind of Rydberg-atom based detection, we perform test measurements on the EHF field emitted from an on-chip radar, planned to be used in automotive industry as a vital sign detector. Our work elucidates practical applications of Rydberg-atom media as well as photonic metamaterial elements.

physics.app-ph↗

arXiv2024

Super-resolution of ultrafast pulses via spectral inversion

The resolution limits of classical spectroscopy can be surpassed by quantum-inspired methods leveraging the information contained in the phase of the complex electromagnetic field. Their counterpart in spatial imaging has been widely discussed and demonstrated; however, the spectral-domain implementations are few and scarce. We experimentally demonstrate a spectroscopic super-resolution method aimed at broadband light (10s to 100s of GHz), and based on the spectral-domain analog of image inversion interferometry. In a proof-of-principle experiment, we study the paradigmatic problem of estimating a small separation between two incoherent spectral features of equal brightness, with a small number of photons per coherence time. On the grounds of asymptotic estimation theory, more than a $2$-fold improvement over the spectral direct imaging is demonstrated in terms of required resources (photons) for a given estimator variance. The setup is based on an actively stabilized Mach-Zehnder-type interferometer with electro-optic time lenses and passive spectral dispersers implementing the inversion. As such, the method promises on-chip integration, good scalability, and further applications e.g. for mode sorting.

physics.optics↗

arXiv2024

Non-classical correlations between photons and phonons of center-of-mass motion of a mechanical oscillator

We demonstrate non-classical correlations between phonons and photons created using opto-mechanical spontaneous parametric down-conversion in a system based on a soft-clamped ultracoherent membrane oscillator inside of a Fabry-Pérot optical resonator. Non-Gaussian quantum features are demonstrated for the center-of-mass motion of a sub-millimeter nanogram-scale mechanical oscillator. We show that phonons stored in the mechanical oscillator, when subsequently read out, display strong signs of quantum coherence, which we demonstrate by single-photon counting enabled by our state-of-the-art optical filtering system. We observe a violation of the classical two-time Cauchy-Schwarz inequality between a heralding write photon and a stored phonon with a confidence of $>92\%$.

quant-ph↗

arXiv2024

Long-lived collective Rydberg excitations in atomic gas achieved via ac-Stark lattice modulation

Collective Rydberg excitations provide promising applications ranging from quantum information processing, and quantum computing to ultra-sensitive electrometry. However, their short lifetime is an immense obstacle in real-life scenarios. The state-of-the-art methods of prolonging the lifetime were mainly implemented for ground-state quantum memories and would require a redesign to effectively work on different atomic transitions. We propose a protocol for extending the Rydberg excitation lifetime, which in principle can freeze the spin-wave and completely cancel the effects of thermal dephasing. The protocol employs off-resonant ac-Stark lattice modulation of spin waves by interfering two laser beams on the atomic medium. Our implementation showed that the excitation lifetime can be extended by an order of magnitude, paving the way towards more complex protocols for collective Rydberg excitations.

quant-ph↗

arXiv2024

Beating the spectroscopic Rayleigh limit via post-processed heterodyne detection

Quantum-inspired superresolution methods surpass the Rayleigh limit in imaging, or the analogous Fourier limit in spectroscopy. This is achieved by carefully extracting the information carried in the emitted optical field by engineered measurements. An alternative to complex experimental setups is to use simple homodyne detection and customized data analysis. We experimentally investigate this method in the time-frequency domain and demonstrate the spectroscopic superresolution for two distinct types of light sources: thermal and phase-averaged coherent states. The experimental results are backed by theoretical predictions based on estimation theory.

quant-ph↗