Ultra-broadband and sensitive cavity optomechanical magnetometry
Abstract
Magnetostrictive optomechanical cavities provide a new optically-readout approach to room temperature magnetometry. Here we report ultrasensitive and ultrahigh bandwidth cavity optomechanical magnetometers constructed by embedding a grain of the magnetostrictive material Terfenol-D within a high quality (Q) optical microcavity on a silicon chip. By engineering their physical structure, we achieve a peak sensitivity of 26 pT/Hz^1/2 comparable to the best cryogenic microscale magnetometers, along with a 3~dB bandwidth as high as 11.3 MHz. Two classes of magnetic response are observed, which we postulate arise from the crystallinity of the Terfenol-D. This allows single- and poly-crystalline grains to be distinguished at the level of a single particle. Our results may enable applications such as lab-on-chip nuclear magnetic spectroscopy and magnetic navigation.
Cite
@article{arxiv.2002.00728,
title = {Ultra-broadband and sensitive cavity optomechanical magnetometry},
author = {Bei-Bei Li and George Brawley and Hamish Greenall and Stefan Forstner and Eoin Sheridan and Halina Rubinsztein-Dunlop and Warwick P. Bowen},
journal= {arXiv preprint arXiv:2002.00728},
year = {2020}
}