arXiv subjects

Gustavo de Oliveira Luiz

Publications and source records attributed to Gustavo de Oliveira Luiz.

3 recordsLinked to original sources

arXiv2026

Exceptional points in diamond optomechanics

Multimode cavity optomechanical systems allow light to couple otherwise non-interacting mechanical resonators, enabling non-Hermitian phenomena such as exceptional points, where eigenfrequencies and eigenvectors of coupled modes coalesce. Accessing an exceptional point and its nearby parameter space is a first step towards chiral mode dynamics and topological state transfer. Diamond optomechanical devices support strong coherent optomechanical coupling required to tune resonances to an exceptional point, as well as strain-coupling to spin-defects for hybrid quantum technologies, but have not yet been used for multimode non-Hermitian physics. Here we tune to an exceptional point in a diamond optomechanical crystal, which uses structural symmetry breaking to produce two high-frequency mechanical resonances coupled to an optical cavity. The exceptional point is reached within a stable operating window below the phonon-lasing threshold, and we observe asymmetric redistribution of optomechanical damping and anti-damping between hybridized modes. These results establish diamond optomechanical crystals as a platform for non-Hermitian optomechanics, opening routes to topological mechanical dynamics in hybrid spin-phonon interfaces.

physics.optics↗

arXiv2022

High frequency torsional motion transduction using optomechanical coupled oscillators

Using light to measure an object's motion is central to operating mechanical sensors that probe forces and fields. Cavity optomechanical systems embed mechanical resonators inside optical resonators. This enhances the sensitivity of optomechanical measurements, but only if the mechanical resonator does not spoil the properties of the optical cavity. For example, cavity optomechanical detection of resonators made from optically absorbing materials, or whose geometry does not possess suitable spatial symmetry, is challenging. Here we demonstrate a system that overcomes challenges in measuring high-frequency twisting motion of a nanodisk by converting them to vibrations of a photonic crystal cavity. Optomechanical readout of the cavity then enables measurement of the nanodisk's torsional resonances with sensitivity $5.1\times 10^{-21}-1.2\times 10^{-19}\,\text{Nm}/\sqrt{\text{Hz}}$ for a mechanical frequency range of 5--800 MHz. The nanodisk can be outfitted with magnetic nanostructures or metasurfaces without affecting the optical properties of the cavity, making the system suitable for torque magnetometry and structured light sensing.

physics.optics↗

arXiv2019

Two-axis cavity optomechanical torque characterization of magnetic microstructures

Significant new functionality is reported for torsion mechanical tools aimed at full magnetic characterizations of both spin statics and dynamics in micro- and nanostructures. Specifically, two orthogonal torque directions are monitored and the results co-analyzed to separate magnetic moment and magnetic susceptibility contributions to torque, as is desired for characterization of anisotropic three-dimensional structures. The approach is demonstrated through application to shape and microstructural disorder-induced magnetic anisotropies in lithographically patterned permalloy, and will have utility for the determination of important magnetic thin-film and multilayer properties including interface anisotropy and exchange bias. The results reflect remarkable sensitivity of the out-of-plane magnetic torque to the nature of small edge domains perpendicular to the applied field direction, and also contain tantalizing indications of direct coupling to spin dynamics at the frequency of the mechanics.

cond-mat.mes-hall↗