arXiv subjects

Anne Louchet-Chauvet

Publications and source records attributed to Anne Louchet-Chauvet.

16 recordsLinked to original sources

arXiv2026

Correlated inhomogeneous absorption profiles across distinct optical transitions in a rare-earth doped crystal

In rare-earth ion-doped crystals, inhomogeneous absorption profiles reflect the distribution of local environments experienced by individual ions. While each optical transition probes this distribution differently, their fine spectral structures may retain correlations arising from shared local perturbations. In this paper, we present a low-temperature, high-resolution spectroscopic study in Er$^{3+}$:YSO of the transition $^{4}I_{15/2}$ - $^{4}I_{11/2}$ at 980 nm and compare it to the well-known transition $^{4}I_{15/2}$ - $^{4}I_{13/2}$ at 1.5 $μ$m. Using spectral hole burning on one transition while monitoring the other, we uncover for the first time spectral correlations between two optical transitions, providing new insight into the microscopic origin of inhomogeneous distributions in rare-earth-doped crystals.

physics.optics↗

arXiv2025

Analog phase-sensitive time-reversal of optically-carried radiofrequency signals

Achieving low-latency time-reversal of broadband radiofrequency signals is crucial for reliable communications in dynamic, uncontrolled environments. However, existing approaches are either digitally assisted -- making broadband extension challenging -- or limited to amplitude modulation. In this work, we report the very first experimental realization of a fully analog, phase-preserving time-reversal architecture for optically-carried radiofrequency signals. The method exploits the exceptional coherence properties of rare-earth ion-doped materials, and leverages the well-established photon echo mechanism, widely used in quantum technologies. While our demonstration is conducted with a modest bandwidth, we identify the fundamental cause of this limitation and propose solutions for future scalability.

physics.optics↗

arXiv2024

Versatile, fast and accurate frequency excursions with a semiconductor laser

Achieving accurate arbitrary frequency excursions with a laser can be quite a technical challenge, especially when steep slopes (GHz/$μ$s) are required, due to both deterministic and stochastic frequency fluctuations. In this work we present a multi-stage correction combining four techniques: pre-distorsion of the laser modulation, iterative correction, opto-electronic feedback loop and feed-forward correction. This combination allows not only to compensate for the non-instantaneous response of the laser to an input modulation, but also to correct in real time the stochastic frequency fluctuations. We implement this multi-stage architecture on a commercial DBR laser and verify its efficiency, first with monochromatic operation and second with highly demanding frequency excursions. We demonstrate that our multi-stage correction not only enables a strong reduction of the laser linewidth, but also allows steep frequency excursions with a relative RMS frequency error well below $1$%, and a laser spectral purity consistently better than $100$~kHz even in the midst of GHz-scale frequency excursions.

physics.optics↗

arXiv2023

Piezo-orbital backaction force in a rare-earth doped crystal

We investigate a system composed of an ensemble of room temperature rare-earth ions embedded in a bulk crystal, intrinsically coupled to internal strain via their sensitivity to the surrounding crystal field. We evidence the generation of a mechanical response under resonant atomic excitation. We find this motion to be the sum of two fundamental, resonant optomechanical backaction processes: a conservative, piezo-orbital mechanism, resulting from the modification of the crystal field associated with the promotion of the ions to their excited state, and a dissipative, non-radiative photothermal process related to the phonons generated throughout the atomic population relaxation. Our work opens new research avenues in hybrid optomechanics, and highlights new interactions that may be key for understanding the dephasing dynamics of ultra-coherent rare-earth ions.

physics.atom-ph↗

arXiv2023

Strain-mediated ion-ion interaction in rare-earth-doped solids

It was recently shown that the optical excitation of rare-earth ions produces a local change of the host matrix shape, attributed to a change of the rare-earth ion's electronic orbital geometry. In this work we investigate the consequences of this piezo-orbital backaction and show from a macroscopic model how it yields a disregarded ion-ion interaction mediated by mechanical strain. This interaction scales as $1/r^3$, similarly to the other archetypal ion-ion interactions, namely electric and magnetic dipole-dipole interactions. We quantitatively assess and compare the magnitude of these three interactions from the angle of the instantaneous spectral diffusion mechanism, and reexamine the scientific literature in a range of rare-earth doped systems in the light of this generally underestimated contribution.

cond-mat.mtrl-sci↗

arXiv2022

Limits to the sensitivity of a rare-earth-enabled cryogenic vibration sensor

Cryogenics is a pivotal aspect in the development of quantum technologies. Closed-cycle devices have recently emerged as an environmentally friendly and low-maintenance alternative to liquid helium cryostats. Yet the larger level of vibrations in dry cryocoolers forbids their use in most sensitive applications. In a recent work, we have proposed an inertial, broadband, contactless sensor based on the piezospectroscopic effect, ie the natural sensitivity of optical lines to strain exhibited by impurities in solids. This sensor builds on the exceptional spectroscopic properties of rare earth ions and operates below 4K, where spectral hole burning considerably enhances the sensitivity. In this paper, we investigate the fundamental and technical limitations of this vibration sensor by comparing a rigid sample attachment to cold stage of a pulse-tube cryocooler and a custom-designed exchange gas chamber for acoustic isolation.

physics.ins-det↗

arXiv2019

Piezospectroscopic measurement of high-frequency vibrations in a pulse-tube cryostat

Vibrations in cryocoolers are a recurrent concern to the end user. They appear in different parts of the acoustic spectrum depending on the refrigerator type, Gifford McMahon or pulse-tube, and with a variable coupling strength to the physical system under interest. Here, we use the piezospectroscopic effect in rare-earth doped crystals at low temperature as a high resolution, contact-less probe for the vibrations. With this optical spectroscopic technique, we obtain and analyze the vibration spectrum up to 700kHz of a 2kW pulse-tube cooler. We attempt an absolute calibration based on known experimental parameters to make our method partially quantitative and to provide a possible comparison with other well-established techniques.

physics.ins-det↗

arXiv2019

Deep and persistent spectral holes in Tm-doped yttrium orthosilicate for imaging applications

With their optical wavelength in the near infrared (790-800nm) and their unique spectroscopic properties at cryogenic temperatures, thulium-doped crystals are at the center of many architectures linked to classical signal processing and quantum information. In this work, we focus on Tm-doped YSO, a compound that was left aside in the mid-1990s due to its rather short optical coherence lifetime. By means of time-resolved hole-burning spectroscopy, we investigate the anisotropic enhanced nuclear Zeeman effect and demonstrate deep, sub-MHz, persistent spectral hole burning under specific magnetic field orientation and magnitude. By estimating the experimental parameters corresponding to a real-scale ultrasound optical tomography setup using Tm:YSO as a spectral filter, we validate Tm:YSO as a promising compound for medical imaging in the human body.

physics.optics↗

arXiv2018

Ultrasound modulated optical tomography in scattering media: flux filtering based on persistent spectral hole burning in the optical diagnosis window

Ultrasound modulated optical tomography (UOT) is a powerful imaging technique to discriminate healthy from unhealthy biological tissues based on their optical signature. Among the numerous detection techniques developed for acousto-optic imaging, only those based on spectral filtering are intrinsically immune to speckle decorrelation. This paper reports on UOT imaging based on spectral hole burning in Tm:YAG crystal under a moderate magnetic field (200G) with a well-defined orientation. The deep and long-lasting holes translate into a more efficient UOT imaging with a higher contrast and faster imaging frame rate. We demonstrate the potential of this method by imaging calibrated phantom scattering gels.

physics.optics↗

arXiv2018

Selective optical addressing of nuclear spins through superhyperfine interaction in rare-earth doped solids

In Er$^{3+}$:Y$_2$SiO$_5$, we demonstrate the selective optical addressing of the $^{89}$Y$^{3+}$ nuclear spins through their superhyperfine coupling with the Er$^{3+}$ electronic spins possessing large Landé $g$-factors. We experimentally probe the electron-nuclear spin mixing with photon echo techniques and validate our model. The site-selective optical addressing of the Y$^{3+}$ nuclear spins is designed by adjusting the magnetic field strength and orientation. This constitutes an important step towards the realization of long-lived solid-state qubits optically addressed by telecom photons.

quant-ph↗

arXiv2015

Optical memory bandwidth and multiplexing capacity in the erbium telecommunication window

We study the bandwidth and multiplexing capacity of an erbium-doped optical memory for quantum storage purposes. We concentrate on the protocol ROSE (Revival of a Silenced Echo) because it has the largest potential multiplexing capacity. Our analysis is applicable to other protocols that involve strong optical excitation. We show that the memory performance is limited by instantaneous spectral diffusion and we describe how this effect can be minimised to achieve optimal performance.

quant-ph↗

arXiv2015

Interlaced spin grating for optical wave filtering

Interlaced Spin Grating is a scheme for the preparation of spectro-spatial periodic absorption gratings in a inhomogeneously broadened absorption profile. It relies on the optical pumping of atoms in a nearby long-lived ground state sublevel. The scheme takes advantage of the sublevel proximity to build large contrast gratings with unlimited bandwidth and preserved average optical depth. It is particularly suited to Tm-doped crystals in the context of classical and quantum signal processing. In this paper, we study the optical pumping dynamics at play in an Interlaced Spin Grating and describe the corresponding absorption profile shape in an optically thick atomic ensemble. We show that, in Tm:YAG, the diffraction efficiency of such a grating can reach 18.3% in the small angle, and 11.6% in the large angle configuration when the excitation is made of simple pulse pairs, considerably outperforming conventional gratings.

quant-ph↗

arXiv2013

Quantum memory for light: large efficiency at telecom wavelength

We implement the ROSE protocol in an erbium doped solid, compatible with the telecom range. The ROSE scheme is an adaptation of the standard 2-pulse photon echo to make it suitable for a quantum memory. We observe an efficiency of 40% in a forward direction by using specific orientations of the light polarizations, magnetic field and crystal axes.

quant-ph↗

arXiv2013

Time reversal of light by linear dispersive filtering near atomic resonance

Based on the similarity of paraxial diffraction and dispersion mathematical descriptions, the temporal imaging of optical pulses combines linear dispersive filters and quadratic phase modulations operating as time lenses. We consider programming a dispersive filter near atomic resonance in rare earth ion doped crystals, which leads to unprecedented high values of dispersive power. This filter is used in an approximate imaging scheme, combining a single time lens and a single dispersive section and operating as a time reversing device, with potential applications in radio-frequency signal processing. This scheme is closely related to three-pulse photon echo with chirped pulses but the connection with temporal imaging and dispersive filtering emphasizes new features.

physics.optics↗

arXiv2012

Adiabatic Passage and Spin Locking in Tm$^{3+}$:YAG

In low concentration Tm$^{3+}$:YAG, we observe efficient adiabatic rapid passage (ARP) of thulium nuclear spin over flipping times much longer than $T_2$. Efficient ARP with long flipping time has been observed in monoatomic solids for decades and has been analyzed in terms of spin temperature and of the thermodynamic equilibrium of a coupled spin ensemble. In low-concentration impurity-doped crystals the spin temperature concept may be questioned. A single spin model should be preferred since the impurity ions are weakly coupled together but interact with the numerous off-resonant matrix ions that originate the spin-spin relaxation. The experiment takes place in the context of quantum information investigation, involving impurity-doped crystals, spin hyperpolarization by optical pumping, and optical detection of the spin evolution.

quant-ph↗

arXiv2010

Entanglement-assisted atomic clock beyond the projection noise limit

We use a quantum non-demolition measurement to generate a spin squeezed state and to create entanglement in a cloud of 10^5 cold cesium atoms, and for the first time operate an atomic clock improved by spin squeezing beyond the projection noise limit in a proof-of-principle experiment. For a clock-interrogation time of 10 μ\s the experiments show an improvement of 1.1 dB in the signal-to-noise ratio, compared to the atomic projection noise limit.

quant-ph↗