arXiv subjects

P. Huillery

Publications and source records attributed to P. Huillery.

15 recordsLinked to original sources

arXiv2026

Scalable Fabrication of Diamond-on-Silica Heterostructures via High-Selectivity Deep ICP-RIE and Room-Temperature Bonding

Single-crystal diamond is a leading material platform for high-power electronics and solid-state quantum technologies, yet many device architectures require micrometer-scale membranes with deeply etched features, patterned from commercially available substrates. In this work, we demonstrate a complete through-etch of a 16 {\mu}m -thick NV-doped single-crystal diamond membrane using a single-layer SiO2 hard mask combined with a multi-step oxygen-based ICPRIE process. With a diamond-to-SiO2 selectivity of 15:1, this non-metallic mask strategy can achieve etch depths of few tens of {\mu}m with well-defined sidewalls, conserved surface roughness and negligible micromasking. Furthermore, we use the oxide layer that remains after etching to serve as the bonding surface in a subsequent integration step. The etched microstructures are transferred onto SiO2 substrates and bonded at room temperature using O2 plasma surface activation and a sodium silicate interlayer. The resulting siloxane film is optically transparent across the visible spectrum and introduces no detectable parasitic photoluminescence, preserving the optical readout of the embedded NV centers. Together, this deep-etch and room-temperature bonding process provides a scalable and contaminationfree route from bulk diamond membranes to diamond-on-silica heterostructures for integrated quantum photonics and sensing applications.

cond-mat.mtrl-sci↗

arXiv2022

Spin-Relaxation of Dipolar-Coupled Nitrogen-Vacancy Centers : The role of Double-flip Processes

We study relaxation processes of the spins of dipolar-coupled negatively charged nitrogen vacancy (NV$^-$) centers under transverse electric and magnetic fields. Specifically, we uncover regimes where flip-flop, double-flip processes as well as mixing induced by local electric fields play a significant role in NV-NV cross-relaxation. Our results are relevant for understanding decoherence in many-body spin systems as well as for high sensitivity magneto- and electro-metry with long-lived interacting solid-state spins. As a proof of principle, we present an orientation and microwave-free magnetometer based on cross-relaxation.

quant-ph↗

arXiv2021

Angle Locking of a Levitating Diamond using Spin-Diamagnetism

The negatively charged nitrogen-vacancy (NV) center in nano- or micro- diamonds has emerged as a promising magnetic field sensor, as a candidate for hyper-polarizing paramagnetic species, as well as a tool for spin-mechanics at the nanoscale. However, NV-doped diamonds are presently not straightforwardly employable for these applications in a liquid or when levitating under atmospheric pressures due to the random angular Brownian motion which tends to rotate the NV quantization axis over the course of the measurments. Here, we report on angle locking of the crystalline axis of a trapped micro-diamond along an external magnetic field. Specifically, we use spin population inversion after a ground state level crossing of the NV center to turn the diamond into a diamagnet. The diamond crystalline axis naturally aligns to the magnetic field with high precision and in the absence of micro-wave, offering bright prospects for applications in biology and spin-mechanical platforms.

quant-ph↗

arXiv2021

Magnetic-Torque Enhanced by Tunable Dipolar interactions

We use tunable dipolar-interactions between the spins of nitrogen-vacancy (NV) centers in diamond to rotate a diamond crystal. Specifically, we employ cross-relaxation between the electronic spin of pairs of NV centers in a trapped diamond to enhance the anisotropic NV paramagnetism and thus to increase the associated spin torque. Our observations open a path towards the use of mechanical oscillators to detect paramagnetic defects that lack optical transitions, to investigation of angular momentum conservation in spin relaxation processes and to novel means of cooling the motion of mechanical oscillators.

cond-mat.mes-hall↗

arXiv2020

Optical Detection of Paramagnetic Defects in a CVD-grown Diamond

The electronic spins of the nitrogen-vacancy centers (NV centers) in Chemical-Vapor-Deposition (CVD) grown diamonds form ideal probes of magnetic fields and temperature, as well as promising qu-bits for quantum information processing. Studying and controlling the magnetic environment of NV centers in such high purity crystals is thus essential for these applications. We demonstrate optical detection of paramagnetic species, such as hydrogen-related complexes, in a CVD-grown diamond. The resonant transfer of the NV centers' polarized electronic spins to the electronic spins of these species generates conspicuous features in the NV photoluminescence by employing magnetic field scans along the [100] crystal direction. Our results offer prospects for more detailed studies of CVD-grown processes as well as for coherent control of the spin of novel classes of hyper-polarized paramagnetic species.

quant-ph↗

arXiv2020

Coherent Microwave Control of a Nuclear Spin Ensemble at Room Temperature

We use nominally forbidden electron-nuclear spin transitions in nitrogen-vacancy (NV) centers in diamond to demonstrate coherent manipulation of a nuclear spin ensemble using microwave fields at room temperature. We show that employing an off-axis magnetic field with a modest amplitude($\approx$ 0.01 T) at an angle with respect to the NV natural quantization axes is enough to tilt the direction of the electronic spins, and enable efficient spin exchange with the nitrogen nuclei of the NV center. We could then demonstrate fast Rabi oscillations on electron-nuclear spin exchanging transitions, coherent population trapping and polarization of nuclear spin ensembles in the microwave regime. Coupling many electronic spins of NV centers to their intrinsic nuclei offers full scalability with respect to the number of controllable spins and provides prospects for transduction. In particular, the technique could be applied to long-lived storage of microwave photons and to the coupling of nuclear spins to mechanical oscillators in the resolved sideband regime.

quant-ph↗

arXiv2020

Spin-mechanics with levitating ferromagnetic particles

We propose and demonstrate first steps towards schemes where the librational mode of levitating ferromagnets is strongly coupled to the electronic spin of Nitrogen-Vacancy (NV) centers in diamond. Experimentally, we levitate ferromagnets in a Paul trap and employ magnetic fields to attain oscillation frequencies in the hundreds of kHz range with Q factors close to $10^4$. These librational frequencies largely exceed the decoherence rate of NV centers in typical CVD grown diamonds offering prospects for sideband resolved operation. We also prepare and levitate composite diamond-ferromagnet particles and demonstrate both coherent spin control of the NV centers and read-out of the particle libration using the NV spin. Our results will find applications in ultra-sensitive gyroscopy and bring levitating objects a step closer to spin-mechanical experiments at the quantum level.

quant-ph↗

arXiv2019

Spin-Cooling of the Motion of a Trapped Diamond

Observing and controlling macroscopic quantum systems has long been a driving force in research on quantum physics. In this endeavor, strong coupling between individual quantum systems and mechanical oscillators is being actively pursued. While both read-out of mechanical motion using coherent control of spin systems and single spin read-out using pristine oscillators have been demonstrated, temperature control of the motion of a macroscopic object using long-lived electronic spins has not been reported. Here, we observe both a spin-dependent torque and spin-cooling of the motion of a trapped microdiamond. Using a combination of microwave and laser excitation enables the spin of nitrogen-vacancy centers to act on the diamond orientation and to cool the diamond libration via a dynamical back-action. Further, driving the system in the non-linear regime, we demonstrate bistability and self-sustained coherent oscillations stimulated by the spin-mechanical coupling, which offers prospects for spin-driven generation of non-classical states of motion. Such a levitating diamond operated as a compass with controlled dissipation has implications in high-precision torque sensing, emulation of the spin-boson problem and probing of quantum phase transitions. In the single spin limit and employing ultra-pure nano-diamonds, it will allow quantum non-demolition read-out of the spin of nitrogen-vacancy centers under ambient conditions, deterministic entanglement between distant individual spins and matter-wave interferometry.

quant-ph↗

arXiv2019

Sub-GHz linewidths ensembles of SiV centers in a diamond nano-pyramid revealed by charge state conversion

Producing nano-structures with embedded bright ensembles of lifetime-limited emitters is a challenge with potential high impact in a broad range of physical sciences. In this work, we demonstrate controlled charge transfer to and from dark states exhibiting very long lifetimes in high density ensembles of SiV centers hosted in a CVD-grown diamond nano-pyramid. Further, using a combination of resonant photoluminescence excitation and a frequency-selective persistent hole burning technique that exploits such charge state transfer, we could demonstrate close to lifetime-limited linewidths from the SiV centers. Such a nanostructure with thousands of bright narrow linewidth emitters in a volume much below $λ^3$ will be useful for coherent light-matter coupling, for biological sensing, and nanoscale thermometry.

quant-ph↗

arXiv2019

Coulomb anti-blockade in a Rydberg dressed gas

We perform a comprehensive investigation of the coupling between a Rydberg-dressed atomic gas and an ultra-cold plasma. Using simultaneous time-resolved measurements of both neutral atoms and ions, we show that plasma formation occurs via a Coulomb anti-blockade mechanism, in which background ions DC Stark shift nearby atoms into resonance at specific distances. The result is a highly correlated growth of the Rydberg population that shares some similarities with that previously observed for van der Waals interactions. We show that a rate equation model that couples the laser-driven Rydberg gas to the ultra-cold plasma via a Coulomb anti-blockade mechanism accurately reproduces both the plasma formation and its subsequent decay. Using long-lived high angular momentum states as a probe, we also find evidence of a crossover from Coulomb anti-blockade to Coulomb blockade at high density. As well as shedding light on loss mechanisms in Rydberg-dressed gases, our results open new ways to create low-entropy states in ultra-cold plasmas.

physics.atom-ph↗

arXiv2018

Ramsey interferences and spin echoes from electron spins inside a levitating macroscopic particle

We report observations of Ramsey interferences and spin echoes from electron spins inside a levitating macroscopic particle. The experiment is realized using nitrogen-vacancy (NV) centers hosted in a micron-sized diamond stored in a Paul trap both under atmospheric conditions and under vacuum. Spin echoes are used to show that the Paul trap preserves the coherence time of the embedded electron spins for more than microseconds. Conversely, the NV spin is employed to demonstrate high angular stability of the diamond even under vacuum. These results are significant steps towards strong coupling of NV spins to the rotational mode of levitating diamonds.

quant-ph↗

arXiv2018

Diamond nano-pyramids with narrow linewidth SiV centers for quantum technologies

Color centers in diamond are versatile solid state atomic-like systems suitable for quantum technological applications. In particular, the negatively charged silicon vacancy center (SiV) can exhibit a narrow photoluminescence (PL) line and lifetime-limited linewidth in bulk diamonds at cryogenic temperature. We present a low-temperature study of chemical vapour deposition (CVD)-grown diamond nano-pyramids containing SiV centers. The PL spectra feature a bulk-like zero-phonon line with ensembles of SiV centers, with a linewidth below 10 GHz which demonstrates very low crystal strain for such a nano-object.

quant-ph↗

arXiv2018

A Rydberg-dressed Magneto-Optical Trap

We propose and demonstrate the laser cooling and trapping of Rydberg-dressed Sr atoms. By off-resonantly coupling the excited state of a narrow (7 kHz) cooling transition to a high-lying Rydberg state, we transfer Rydberg properties such as enhanced electric polarizability to a stable magneto-optical trap operating at $< 1 μK$. By increasing the density to $1 \times 10^{12} \rm{cm^{-3}}$, we show that it is possible to reach a regime where the long-range interaction between Rydberg-dressed atoms becomes comparable to the kinetic energy, opening a route to combining laser cooling with tunable long-range interactions.

physics.atom-ph↗

arXiv2013

Full counting statistics and phase diagram of a dissipative Rydberg gas

Ultra-cold gases excited to strongly interacting Rydberg states are a promising system for quantum simulations of many-body systems. For off-resonant excitation of such systems in the dissipative regime, highly correlated many-body states exhibiting, among other characteristics, intermittency and multi-modal counting distributions are expected to be created. So far, experiments with Rydberg atoms have been carried out in the resonant, non-dissipative regime. Here we realize a dissipative gas of rubidium Rydberg atoms and measure its full counting statistics for both resonant and off-resonant excitation. We find strongly bimodal counting distributions in the off-resonant regime that are compatible with intermittency due to the coexistence of dynamical phases. Moreover, we measure the phase diagram of the system and find good agreement with recent theoretical predictions. Our results pave the way towards detailed studies of many-body effects in Rydberg gases.

cond-mat.quant-gas↗

arXiv2011

Observation of a resonant four-body interaction in cold cesium Rydberg atoms

Cold Rydberg atoms subject to long-range dipole-dipole interactions represent a particularly interesting system for exploring few-body interactions and probing the transition from 2-body physics to the many-body regime. In this work we report the direct observation of a resonant 4-body Rydberg interaction. We exploit the occurrence of an accidental quasi-coincidence of a 2-body and a 4-body resonant Stark-tuned Forster process in cesium to observe a resonant energy transfer requiring the simultaneous interaction of at least four neighboring atoms. These results are relevant for the implementation of quantum gates with Rydberg atoms and for further studies of many-body physics.

physics.atom-ph↗