arXiv subjects

Jérémy Bon

Publications and source records attributed to Jérémy Bon.

4 recordsLinked to original sources

arXiv2025

Optomechanical disk resonator in the quantum ground state of motion

Although they have enabled several advances in the field of optomechanics, optomechanical disk resonators have not yet been operated in the quantum regime. We present the first experimental demonstration of an optomechanical disk resonator prepared in the quantum ground state. With a gigahertz frequency, the mechanical breathing mode of the investigated semiconductor disk reaches a level of excitation below a single phonon when cooled in a dilution refrigerator. We quantify the phonon occupancy of the mechanical mode by performing Brillouin sideband spectroscopy: a conical optical fiber is evanescently coupled to the disk optical whispering-gallery mode, and Stokes and anti-Stokes photons scattered by phonon emission and absorption are counted on a single-photon detector. We measure a suppression of the absorption process corresponding to a phonon occupancy of $0.66\pm0.20$. We experimentally investigate the mechanisms ruling laser-induced heating, which limits the lowest measurable phonon occupancy, and notably witness an extra-cavity heating effect.

quant-ph↗

arXiv2022

Probing the acoustic losses of graphene with a low-loss quartz bulk-acoustic-wave resonator at cryogenic temperatures

We observe mechanical effects of an exfoliated graphene monolayer deposited on a quartz crystal substrate designed to operate as an extremely low-loss bulk-acoustic-wave cavity at liquid-helium temperature.This is achieved by sensing overtones of the three thickness eigen-modes of the so-called SC-cut, since all three modes, two shear mode and one extensional mode, can be electrically probed with such a crystal cut. From quality-factor measurements, the mechanical losses of the adhesive graphene monolayer are assessed to be about 8 x 10-4 at 4 K in the best case. They are therefore significantly greater than those already reported for suspended membranes but also for adherent layers on SiO2/Si substrates operating in torsional modes. In fact, results reveal that surface scattering occurs due to a roughness degradation of a factor 7. In addition, the mechanical losses presented here are also placed in the context of a device submitted to thermomechanical stresses, but which are not the only ones existing. Some of them could be intrinsic ones related to the deposition process of the graphene layer. Based on a force-frequency theory applied to the three thickness modes which react differently to stresses, it is demonstrated that this stress effect actually entangled with that of mass loading reconciles the experimental results.

physics.app-ph↗

arXiv2020

An optomechanical discrete variable quantum teleportation scheme

We propose an experimental protocol to realize discrete variable quantum teleportation using optomechanical devices. The photonic polarization superposition state of a single photon is teleported to a phononic superposition of two micromechanical oscillators by means of photon/phonon entanglement generation and optical Bell state measurement using two-photon interference. Verification of the protocol is performed by coherent state transfer between the mechanical devices and light. Simulations show the feasibility of the proposed scheme at millikelvin temperatures using state-of-the-art gigahertz optomechanical devices.

quant-ph↗

arXiv2016

Temperature coefficients of crystalline-quartz elastic constants over the cryogenic range [4 K, 15 K]

This paper brings out results of a measurement campaign aiming to determine the temperature coefficients of synthetic quartz elastic constants at liquid helium temperature. The method is based on the relationship between the resonance frequencies of a quartz acoustic cavity and the elastic constants of the material. The temperature coefficients of the elastic constants are extracted from experimental frequency-temperature data collected from a set of resonators of various cut angles, because of the anisotropy of quartz, measured on the very useful cryogenic range [4 K - 15 K]. The knowledge of these temperature coefficients would allow to further design either quartz temperature sensors or conversely frequency-temperature compensated quartz cuts. With extremely low losses, lower than $10^{-9}$ for the best ones, key applications of such devices are ultra-low loss mechanical systems used in many research areas including frequency control and fundamental measurements. The Eulerian formalism is used in this study to identify the temperature coefficients.

cond-mat.other↗