arXiv subjects

Rémy Vicarini

Publications and source records attributed to Rémy Vicarini.

4 recordsLinked to original sources

arXiv2024

Short-term stability of a microcell optical reference based on Rb atom two-photon transition at 778 nm

We report on the development and short-term stability characterization of an optical frequency reference based on the spectroscopy of the rubidium two-photon transition at 778 nm in a microfabricated vapor cell. When compared against a 778 nm reference signal extracted from a frequency-doubled cavity-stabilized telecom laser, the short-term stability of the microcell frequency standard is 3.5 $\times$ 10$^{-13}$ $τ^{-1/2}$ until 200~s, in good agreement with a phase noise level of $+$ 43 dBrad$^2$/Hz at 1~Hz offset frequency. The two main contributions to the short-term stability of the microcell reference are currently the photon shot noise and the intermodulation effect induced by the laser frequency noise. With still a relevant margin of progress, these results show the interest of this spectroscopic approach for the demonstration of high-stability miniaturized optical vapor cell clocks. Such clocks are poised to be highly beneficial for applications in navigation, communications, and metrology.

physics.atom-ph↗

arXiv2023

Sub-Doppler spectroscopy of the near-UV Cs atom 6S$_{1/2}$-7P$_{1/2}$ transition in a microfabricated vapor cell

We report on the characterization of sub-Doppler resonances detected by probing the 6S$_{1/2}$-7P$_{1/2}$ transition of Cs atom at 459 nm in a microfabricated vapor cell. The dependence of the sub-Doppler resonance (linewidth, amplitude) on some key experimental parameters, including the laser intensity and the cell temperature, is investigated. These narrow atomic resonances are of interest for high-resolution spectroscopy, instrumentation, and may constitute the basis of a near-UV microcell optical standard.

physics.atom-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↗

arXiv2022

Laser-actuated hermetic seals for integrated atomic devices

Atomic devices such as atomic clocks and optically-pumped magnetometers rely on the interrogation of atoms contained in a cell whose inner content has to meet high standards of purity and accuracy. Glass-blowing techniques and craftsmanship have evolved over many decades to achieve such standards in macroscopic vapor cells. With the emergence of chip-scale atomic devices, the need for miniaturization and mass fabrication has led to the adoption of microfabrication techniques to make millimeter-scale vapor cells. However, many shortcomings remain and no process has been able to match the quality and versatility of glass-blown cells. Here, we introduce a novel approach to structure, fill and seal microfabricated vapor cells inspired from the century-old approach of glass-blowing. In particular we demonstrate opening and closing single-use zero-leak microfabricated valves, actuated exclusively by laser, and operating in the same way as the "make-seals" and "break-seals" found in the filling apparatus of traditional cells. Such structures are employed to fill cesium vapor cells at the wafer-level. The make-seal structure consists of a glass membrane that can be locally heated and deflected to seal a microchannel. The break-seal is obtained by breaching a silicon wall between cavities. This new approach allows adapting processes previously restricted to glass-blown cells. It can also be extended to vacuum microelectronics and vacuum-packaging of micro-electro-mechanical systems (MEMS) devices.

physics.atom-ph↗