Anne LOUCHET-CHAUVET

Anne LOUCHET-CHAUVET Chargée de recherche au CNRS Tél. : 01 80 96 30 42 Pièce : R24 Courriel :

Thèmes de recherche

• Retournement temporel analogique de signaux RF
• Filtrage pour l’imagerie acousto-optique en milieu diffusant
• Conception et développement d’architectures de traitement du signal
• Optomécanique dans les cristaux dopés terre rare

Propositions de stage ou de thèse

Effets thermiques et décohérence dans les cristaux dopés : Proposition à télécharger ici

• N’hésitez pas à nous contacter

Actualités

• janvier 2023 : Notre théorie sur l’interaction ion-ion véhiculée par la contrainte dans les solides dopés est publiée dans Journal of Physics : Condensed Matter !
• décembre 2022 : publication de nos travaux sur les premières images acousto-optiques in-vivo dans Biomedical Optics Express !
• décembre 2022 : Lothaire Ulrich a soutenu sa thèse de doctorat à Thales TRT, intitulée "Spectro-spatial architectures in rare-earth ion-doped crystals for wideband radiofrequency signal processing". Bravo Lothaire !
• juillet 2022 : publication de nos travaux sur la réalisation d’un filtre agile haute performance pour les signaux RF dans un cristal dopé dans IEEE Journal of Lightwave Photonics.
• avril 2022 : publication de nos mesures de vibrations ultra-sensibles en milieu cryogénique dans le numéro spécial "Quantum Acoustics" de AVS Quantum Science.
• octobre 2021 : arrivée de Thomas Llauze pour une thèse de 3 ans sur le retournement temporel analogique de signaux RF.
• septembre 2021 : pré-publication sur notre observation de l’action en retour optomécanique dans un cristal dopé aux ions de terre rare
• juillet 2021 : arrivée de Quang-Minh Thai pour un post-doc sur l’imagerie acousto-optique in-vivo.
• mai 2021 : arrivée de Félix Montjovet pour un stage sur le contrôle des chirps d’un laser DBR.
• mai 2020 : publication de notre démonstration d’analyse spectrale large bande de signaux radio-fréquence sur porteuse optique à longueur d’onde télécom
• février 2020 : publication de nos travaux sur la mise au point d’un matériau amélioré pour le traitement de signaux optiques, une collaboration avec l’IRCP et Thales Research&Technology.
• juillet 2019 : notre projet sur le retournement temporel de signaux RF est financé par l’ANR ! Voir le site dédié ici
• décembre 2019 : arrivée de Lothaire Ulrich pour une thèse CIFRE de 3 ans sur le filtrage et l’analyse spectrale de signaux RF, à Thales R&T.
• mai 2019 : dépôt du brevet "Matériau amélioré pour le traitement spectro-spatial de signaux optiques", en collaboration avec l’IRCP et Thales RT.

Collaborations

• François Ramaz et Maïmouna Bocoum (Institut Langevin) : imagerie acousto-optique en milieu diffusant
• Thierry Chanelière, Jean-Philippe Poizat (Institut Néel) : architectures de traitement de signal classiques et quantiques et spectroscopie dans les cristaux dopés
• Alban Ferrier, Philippe Goldner (Chimie ParisTech) : croissance et spectroscopie de matériaux dopés
• Loïc Morvan, Perrine Berger, Sacha Welinski (Thales Research & Technology) : architectures de traitement de signaux radar
• Johanne Seguin, Nathalie Mignet (UTCBS) : imagerie médicale

Publications à l’Institut Langevin

Strain-mediated ion-ion interaction in rare-earth-doped solids Louchet-Chauvet, A., and T. Chanelière Journal of Physics Condensed Matter 35, no. 30, 305501 (2023) Résumé: 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/r3, 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 re-examine the scientific literature in a range of rare-earth doped systems in the light of this generally underestimated contribution.
In vivo ultrasound modulated optical tomography with a persistent spectral hole burning filter Thai, Q. M., G. Kalot, C. Venet, J. Seguin, M. Bocoum, N. Mignet, F. Ramaz, and A. Louchet-Chauvet Biomedical Optics Express 13, no. 12, 6484-6496 (2022) Résumé: We present in vivo ultrasound modulated optical tomography (UOT) results on mice, using the persistent spectral hole burning (PSHB) effect in a Tm3+:YAG crystal. Indocyanine green (ICG) solution was injected as an optical absorber and was clearly identified on the PSHB-UOT images, both in the muscle (following an intramuscular injection) and in the liver (following an intravenous injection). This demonstration also validates an experimental setup with an improved level of performance combined with an increased technological maturity compared to previous demonstrations.
High rejection and frequency agile optical filtering of RF signals using a rare earth ion-doped crystal Ulrich, L., S. Welinski, A. Louchet-Chauvet, J. D. Rosny, D. Dolfi, C. Vaneph, P. Berger, and L. Morvan Journal of Lightwave Technology 40, no. 20, 6901-6910 (2022) Résumé: While photonics is broadly considered as a leading solution for analog RF processing, photonic RF filters often show a limited out-of-band rejection. In this work we demonstrate a high rejection and high steepness photonic RF bandpass filter based on spectral hole burning in a rare earth ion-doped crystal. The filter is obtained by programming a frequency-selective absorption grating in the crystal. With an experimental and theoretical study we identify the optimal parameters for this filter. We achieve a remarkable rejection of 60 dB and a rejection of 45 dB at 50 MHz from the edge of the filter, compliant with most demanding applications.
Limits to the sensitivity of a rare-earth-enabled cryogenic vibration sensor Louchet-Chauvet, A., and T. Chanelière AVS Quantum Science 4, no. 2, 024401 (2022) Résumé: 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, i.e., 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 4 K, 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 the cold stage of a pulse-tube cryocooler and a custom-designed exchange gas chamber for acoustic isolation.
Telecom wavelength optical processor for wideband spectral analysis of radiofrequency signals Louchet-Chauvet, A., P. Berger, P. Nouchi, D. Dolfi, A. Ferrier, P. Goldner, and L. Morvan Laser Physics 30, no. 6 (2020) Résumé: © 2020 Astro Ltd. In this paper we present a spectral analyzer for wideband RF signals with a spectral hole-burning-based architecture operating at telecom wavelength. This device is based on a codoped Er3 +:Sc3 +:Y2SiO5 crystal whose inhomogeneous linewidth allows for wideband operation. With time-resolved holeburning spectroscopy experiments we study the homogeneous linewidth and spectral diffusion in an unusual magnetic field configuration. We finally demonstrate the spectral analysis of RF signals with 28 GHz instantaneous bandwidth and MHz resolution. This work opens the way towards more complex architectures such as direction finding with wideband capacity. Mots-clés: rare-earth doped crystals; spectral analysis; spectral holeburning
Tailoring the 3F4 level lifetime in Tm3+: Y3Al5O12 by Eu3+ co-doping for signal processing application Zhang, Z., A. Louchet-Chauvet, L. Morvan, P. Berger, P. Goldner, and A. Ferrier Journal of Luminescence 222 (2020) Résumé: © 2020 Elsevier B.V. Tm3+: Y3Al5O12 (Tm:YAG) crystal is a promising material for high-resolution spectral analysis of broadband radio-frequency (RF) signals, where the absorption spectrum is modified via spectral hole burning. In Tm:YAG, the efficiency of the spectral tailoring is limited by the long-lived metastable level 3F4, acting as a bottleneck for the optical pumping mechanism. We demonstrate that co-doping Tm:YAG with Eu3+ ions can significantly shorten the optical lifetime of 3F4 state, while that of 3H4 is essentially conserved. We show with a model that these modified lifetimes allow faster tailoring of the absorption profile. Because of their low cost and easiness of processing, we use Tm3+ and Eu3+ co-doped Y3Al5O12 ceramics to probe the energy transfer efficiency and find the optimal cation co-doping concentration. Furthermore, we show that Eu3+ co-doping increases the inhomogeneous broadening on the Tm3+ optical transition, hence the spectral analysis bandwidth. Finally, we confirm these results on a single crystal grown by the Czochralski method. Mots-clés: Crystal growth; Rare earth spectroscopy; RF signal processing; Tm,Eu:YAG crystal
Structured ultrasound-modulated optical tomography Bocoum, M., J. L. Gennisson, J. B. Laudereau, A. Louchet-Chauvet, J. M. Tualle, and F. Ramaz Applied Optics 58, no. 8, 1933-1940 (2019) Résumé: © 2019 Optical Society of America Ultrasound-modulated optical tomography (UOT) is an imaging technique that couples light and ultrasound in order to perform in-depth imaging of highly scattering media. In previous work, we introduced plane wave UOT, an imaging method analogous to x-ray tomography based on the filtered backprojection for image reconstruction. Angle-limited measurements, however, led to drastic loss of lateral spatial resolution. Here, we present a new structured ultrasonic plane wave UOT method that allows partial recovery of the resolution. For image reconstruction, we present a generalization of the Fourier slice theorem along with a generalized filtered backprojection formalism. The method is successfully tested on simulated and experimental data.
Deep and persistent spectral holes in thulium-doped yttrium orthosilicate for imaging applications Venet, C., B. Car, L. Veissier, F. Ramaz, and A. Louchet-Chauvet Physical Review B 99, no. 11 (2019) Résumé: © 2019 American Physical Society. With their optical wavelength in the near infrared (790-800 nm) 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.
Ultrasound-modulated optical tomography in scattering media: Flux filtering based on persistent spectral hole burning in the optical diagnosis window Venet, C., M. Bocoum, J. B. Laudereau, T. Chaneliere, F. Ramaz, and A. Louchet-Chauvet Optics Letters 43, no. 16, 3993-3996 (2018) Résumé: © 2018 Optical Society of America. 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 Letter 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.
High resolution, large dynamic range spectral filtering at 800 nm using Tm:YAG crystals Louchet-Chauvet, A., R. Lauro, P. Goldner, F. Ramaz, T. Chanelière, and J.-L. Le Gouët Proceedings of SPIE - The International Society for Optical Engineering 7948 (2011) Résumé: Thulium-doped crystals are considered for programmable filtering. Such a filter can be acllieved by Spectral Hole Burning (SHB). One optically pumps the active ions into a long-lived shelving state, opening a narrow transparency window in the crystal absorption band. We investigate a new shelving scheme in Tm:YAG where the thulium ions are pumped into a ground state nuclear Zeeman sublevel, instead of their natural 10ms-lifetime metastable state. The shelving time is increased to several seconds, reducing the residual population in the transparency window by orders of magnitude. This should enhance the filter's dynamic range, which is essential in demanding filtering applications like ultrasound optical tomography. © 2011 SPIE. Mots-clés: High-resolution spectral filtering; Rare-earth ion-doped crystals; Spectral hole-burning; Ultrasound-modulated optical tomography; Active ions; Crystal absorption; Doped crystals; Dynamic range; Filtering applications; High resolution; Meta-stable state; Orders of magnitude; Rare earth ions; Spectral filtering; Spectral hole-burning; Thulium ions; Ultrasound-modulated optical tomography; YAG; YAG crystal; Crystals; Erbium doped fiber amplifiers; Ions; Optical tomography; Quantum computers; Quant

Publications antérieures

Optical study of the anisotropic erbium spin flip-flop dynamics B. Car, L. Veissier, A. Louchet-Chauvet, J.-L. Le Gouët, T. Chanelière Phys. Rev. B 100, 165107 (2019) Résumé: We investigate the erbium flip-flop dynamics as a limiting factor of the electron-spin lifetime and more generally as an indirect source of decoherence in rare-earth-doped insulators. Despite the random isotropic arrangement of dopants in the host crystal, the dipolar interaction strongly depends on the magnetic field orientation following the strong anisotropy of the g factor. In Er3+Y2SiO5, we observe in a 10-ppm doped sample a 3 orders-of-magnitude variation of the erbium flip-flop rate, as expected from the dipolar coupling term between identical spins with an anisotropic g tensor. We can estimate the correct order of magnitude for a 50-ppm concentration, but we can only reproduce qualitatively the orientational variation of the flip-flop rate.
Piezospectroscopic measurement of high-frequency vibrations in a pulse-tube cryostat A. Louchet-Chauvet, R. Ahlefeldt, T. Chanelière Review of Scientific Instruments 90, 034901 (2019) Résumé: 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 a 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 700 kHz of a 2 kW 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.
Two-pulse photon echo area theorem in an optically dense medium R. Urmancheev, K. Gerasimov, M. Minnegaliev, T. Chanelière, A. Louchet-Chauvet, S. Moiseev Optics Express 27, 28983 (2019) Résumé: We perform a theoretical and experimental study of the two-pulse photon echo area conservation law in an optically dense medium. The experimental properties of the echo signal are studied at 4K on the optical transition 3H 6(1)→3H 4(1) (793 nm) of Tm3+ in a YAG crystal for a wide range of pulse areas of the two incoming light pulses, up to 𝜃1=4𝜋 and 𝜃2≈7𝜋 respectively, with optical depth 1.5. We analyze the experimental data by using the analytic solution of the photon echo area theorem for plane waves. We find that the transverse Gaussian spatial profile of the beam leads to an attenuation of the echo area nutation as function of θ1 and θ2. Additional spatial filtering of the photon echo beam allows to recover this nutation. The experimental data are in good agreement with the solution of photon echo pulse area theorem for weak incoming pulse areas 𝜃1,2≲𝜋. However at higher pulse areas, the observations diverge from the analytic solution requiring further theoretical and experimental studies.
Analog time-reversal of optically-carried RF signals with a rare earth ion-doped processor with broadband potential A. Louchet-Chauvet 2018 International Topical Meeting on Microwave Photonics (2018) Résumé: We propose a novel analog architecture for time-reversing optically carried RF signals, based on a rare-earth atomic processor. Our scheme combines long processed signals duration (over 10 μs), potentially GHz bandwidth, direct access to the signal field amplitude, and compatibility with phase-modulated signals. The combination of these features makes this architecture ideal for refocusing RF signals distorted by their propagation in a reverberating environment.
Rate equation reformulation including coherent excitation: application to periodic protocols based on spectral holeburning Y. Attal, P. Berger, L. Morvan, P. Nouchi, D. Dolfi, T. Chanelière, A. Louchet-Chauvet J. Opt. Soc. Am. B 35, 1260 (2018) Résumé: A large number of signal-processing protocols are based on recording a spectral pattern via spectral hole-burning in an inhomogeneously broadened absorption profile. We present a simulation method specifically designed for periodic excitation sequences leading to the creation of a spectral pattern. This method is applicable to any multilevel atomic structure. The atomic variables’ coherent dynamics are solved for a single temporal excitation step. The result is expressed as an equivalent population transfer rate. This way, the whole sequence is described as a matrix product and the steady state of the system under periodic excitation is easily derived. The propagation through the atomic medium is fully decoupled from the temporal evolution. We apply this method to the engraving of a spectral grating in a large-absorption Tm:YAG sample for wideband spectral analysis.
Selective optical addressing of nuclear spins through superhyperfine interaction in rare-earth doped solids B. Car, L. Veissier, A. Louchet-Chauvet, J.-L. Le Gouët, T. Chanelière Phys. Rev. Lett. 120, 197401 (2018) Résumé: In Er3+:Y2SiO5, we demonstrate the selective optical addressing of the 89Y3+ nuclear spins through their superhyperfine coupling with the Er3+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 Y3+ 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.
Effects of disorder on optical and electron spin linewidths in Er3+,Sc3+:Y2SiO5 S. Welinski, C. W. Thiel, J. Dajczgewand, A. Ferrier, R. L. Cone, R. M. Macfarlane, T. Chanelière, A. Louchet-Chauvet, Ph. Goldner Optical Materials 63, 69 (2017) Résumé: The material Er3+:Y2SiO5 co-doped with Sc3+ is investigated for applications in optical quantum storage and signal processing. Replacing 1% of the Y3+ in the crystal with Sc3+ introduces static strain into the lattice that increases the inhomogeneous linewidth of the Er3+ optical transition at 1.536 μm to 25 GHz, a 50-fold increase compared to Er3+:Y2SiO5 samples without Sc3+ co-doping. Electron paramagnetic resonance spectroscopy shows that electron spin linewidths are also strongly increased, confirming the previously proposed mechanism for decoherence suppression by using disorder to inhibit resonant spin-spin interactions. Analysis of the spin line broadening as a function of magnetic field orientation indicates the presence of contributions that cannot be modeled by a simple change in the electronic g tensor. Optical homogeneous linewidths of less than 2 kHz are observed for a weak magnetic field of 0.1 T and also for fields greater than 2 T with the field oriented near the D2 crystal axis and at a temperature of 1.7 K. These results suggest that this material can be useful for high-bandwidth classical and quantum information processing in the telecom C-band.
Quantum memory in an orthogonal geometry of silenced echo retrieval K.I. Gerasimov, M.M. Minnegaliev, S.A. Moiseev, R.V. Urmancheev, T. Chanelière, A. Louchet-Chauvet Optics and Spectroscopy 123, no. 2, 211 (2017) Résumé: We experimentally realize a quantum-memory protocol based on retrieval of silenced echo (ROSE) in Tm3+:Y3Al5O12 crystal in an orthogonal geometry of the signal and control light fields. The silenced echo signal revival efficiency of ~13% with 36 μs storage time is demonstrated. To achieve that we implemented a high-precision atomic coherence control via amplitude- and phase-modulated laser pulses. We also discuss capabilities of this configuration, ways to increase quantum efficiency and to combine it with a single-mode optical cavity.
Scandium doped Tm:YAG ceramics and single crystals : coherent and high resolution spectroscopy A. Ferrier, S. Ilas, P. Goldner, A. Louchet-Chauvet Journal of Luminescence 194, 116 (2017) Résumé: We report a detailed study about the effect of Scandium (Sc3+) doping on the 3H6-3H4 transition in Tm3+:Y3Al5O12 ceramics at cryogenic temperature. Inhomogeneous, homogeneous linewidths and Zeeman lifetime as a function of the Sc3+ codoping are presented and compared to values obtained in single crystals. We demonstrate that Sc3+ can be used to increase the inhomogeneous broadening without being detrimental to coherence properties and spectral hole persistence. This controlled disorder therefore provides larger bandwidth for signal processing applications such as spectral analyzers and quantum information processing. Moreover, we show that opaque ceramics prepared by simple solid-state reaction exhibit a long coherence lifetime and even narrower inhomogeneous linewidths than single crystals. Opaque ceramics are very attractive for material development because they offer ease and low cost of fabrication and enable the study of a larger range of composition compared to single crystals. However we show that the manufacturing and the initial stoichiometry of the ceramics have a significant impact on the inhomogeneous broadening.
RF spectrum analyzer for pulsed signals: ultra-wide instantaneous bandwidth, high sensitivity and high time-resolution P Berger, Y Attal, M Schwarz, S Molin, A Louchet-Chauvet, T Chanelière, J-L Le Gouët, D Dolfi, L Morvan Journal of Lightwave Technology 34, 4658 (2016) Résumé: We report on the experimental demonstration of a multi-gigahertz bandwidth RF spectrum analyzer based on spectral hole burning in a 3 K-cooled rare-earth ion-doped crystal. We implemented the so-called “rainbow” architecture in which the optically carried spectral components of the incoming signal are angularly separated by the crystal, and are then acquired with a pixelated photo-detector. With this setup, we have been able to monitor and record the spectrum of complex microwave signals over an instantaneous bandwidth above 20 GHz, with a time resolution below 100 μs, 400 resolvable frequency components and a 100% probability of intercept. RF pulsed signals in the μs range are perfectly analyzed with this high time-resolved set-up. The best achievable sensitivity for pulsed signals is computed and compared with another spectral hole burning technique.
Interlaced spin grating for optical wave filtering H. Linget, T. Chanelière, J.-L. Le Gouët, P. Berger, L. Morvan, A. Louchet-Chauvet Physical Review A 91, 023804 (2015) Résumé: Interlaced spin grating is a scheme for the preparation of spectrospatial periodic absorption gratings in an 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.
Optical measurement of heteronuclear cross-relaxation interactions in Tm:YAG R. L. Ahlefeldt, M. F. Pascual-Winter, A. Louchet-Chauvet, T. Chanelière, J.-L Le Gouët Physical Review B 92, 094305 (2015) Résumé: We investigate cross-relaxation interactions between Tm and Al in Tm3+:YAG using two optical methods: spectral hole burning and stimulated echoes. These interactions lead to a substantial reduction in the hyperfine lifetime at magnetic fields that bring the Tm hyperfine transition into resonance with an Al transition. We develop models for the measured echo decay curves and hole-burning spectra near a resonance, which are used to show that the Tm-Al interaction has a resonance width of 12±3 kHz and reduces the hyperfine lifetime at resonance to 0.5±0.3 ms.
Optical memory bandwidth and multiplexing capacity in the erbium telecommunication window J. Dajczgewand, R. Ahlefeldt, T. Böttger, A. Louchet-Chauvet, J.-L.Le Gouet, T. Chanelière New Journal of Physics 17, 023031 (2015) Résumé: We study the bandwidth and multiplexing capacity of an erbium-doped optical memory for quantum storage purposes. We concentrate on the protocol 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 minimized to achieve optimal performance.
Cristaux et dispositifs optiques pour le traitement de l'information quantique T. Chanelière, A. Louchet-Chauvet, A. Ferrier, P. Goldner, Techniques de l'Ingénieur, e6367 (2014)
Détermination de l'accélération de la pesanteur pour la balance du watt du LNE S Merlet, P Gillot, T Farah, Q Bodart, J Le Gouët, P Cheinet, C Guerlin, A Louchet-Chauvet, N Malossi, A Kopaev, O Francis, G D'Agostino, M Diament, G Geneves, A Clairon, A Landragin, F Pereira Dos Santos Revue Française de Métrologie 36, 11-27 (2014) Résumé: Le projet « balance du watt » propose de relier la définition du kilogramme à la constante de Planck. La pesée de la masse impliquée nécessite une détermination de l’accélération de la pesanteur g avec une exactitude meilleure que 10-8. Les travaux résumés dans cet article visent à réaliser cette détermination à l’aide d’un gravimètre atomique et d’un site gravimétrique dédié.
Large efficiency at telecom wavelength for optical quantum memories J. Dajczgewand, J.-L. Le Gouët, A. Louchet-Chauvet, T. Chanelière Optics Letters 39, 2711 (2014) Résumé: We implement the ROSE protocol in an erbium-doped solid, compatible with the telecom range. The ROSE scheme is an adaptation of the standard two-pulse photon echo to make it suitable for a quantum memory. We observe a retrieval efficiency of 40% for a weak laser pulse in the forward direction by using specific orientations of the light polarizations, magnetic field, and crystal axes.
Photon echo with a few photons in two-level atoms M. Bonarota, J. Dajczgewand, A. Louchet-Chauvet, J.-L. Le Gouët, T. Chanelière Laser Physics 24, 094003 (2014) Résumé: To store and retrieve signals at the single photon level, various photon echo schemes have resorted to complex preparation steps involving ancillary shelving states in multi-level atoms. For the first time, we experimentally demonstrate photon echo operation at such a low signal intensity without any preparation step, which allows us to work with mere two-level atoms. This simplified approach relies on the so-coined 'revival of silenced echo' (ROSE) scheme. Low noise conditions are obtained by returning the atoms to the ground state before the echo emission. In the present paper we manage ROSE in photon counting conditions, showing that very strong control fields can be compatible with extremely weak signals, making ROSE consistent with quantum memory requirements.
Time reversal of light by linear dispersive filtering near atomic resonance H. Linget, T. Chanelière, J-L Le Gouët and A Louchet-Chauvet New J. Phys. 15, 063037 (2014) Résumé: 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 a three-pulse photon echo with chirped pulses, but the connection with temporal imaging and dispersive filtering emphasizes new features.
Time-reversal of optically-carried radiofrequency signals in the microsecond range H. Linget, L. Morvan, J.-L. Le Gouët and A. Louchet-Chauvet Optics Letters 38, 643 (2013) Résumé: The time-reversal (TR) protocol we implement in an erbium-doped YSO crystal is based on photon echoes but avoids the storage of the signal to be processed. Unlike other approaches implying digitizing or highly dispersive optical fibers, the proposed scheme reaches the μs range and potentially offers high bandwidth, both required for RADAR applications. In this Letter, we demonstrate faithful reversal of arbitrary pulse sequences with 6 μs duration and 10 MHz bandwidth. To the best of our knowledge, this is the first demonstration of TR via linear filtering in a programmable material.
Adiabatic passage with spin locking in Tm3+:YAG M. F. Pascual-Winter, R.-C. Tongning, R. Lauro, A. Louchet-Chauvet, T. Chanelière, J.-L. Le Gouët Phys. Rev. B 86, 064301 (2012) Résumé: In low-concentration Tm3+:YAG, we observe efficient adiabatic rapid passage (ARP) of thulium nuclear spin over flipping times much longer than T2. 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.
Revival of silenced echo and quantum memory for light V. Damon, M. Bonarota, A. Louchet-Chauvet, T. Chanelière, J.-L. Le Gouët New J. Phys. 13, 093031 (2011) Résumé: We propose an original quantum memory protocol. It belongs to the class of rephasing processes and is closely related to two-pulse photon echo. It is known that the strong population inversion produced by the rephasing pulse prevents the plain two-pulse photon echo from serving as a quantum memory scheme. Indeed, gain and spontaneous emission generate prohibitive noise. A second π-pulse can be used to simultaneously reverse the atomic phase and bring the atoms back into the ground state. Then a secondary echo is radiated from a non-inverted medium, avoiding contamination by gain and spontaneous emission noise. However, one must kill the primary echo, in order to preserve all the information for the secondary signal. In the present work, spatial phase mismatching is used to silence the standard two-pulse echo. An experimental demonstration is presented.