Author Affiliations
Abstract
1 Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
2 School of Mathematics and Physics, The University of Queensland, St Lucia, QLD 4072, Australia
Magnetostrictive optomechanical cavities provide a new optical 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 () optical microcavity on a silicon chip. By engineering their physical structure, we achieve a peak sensitivity of 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 crystalline and polycrystalline 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.
Photonics Research
2020, 8(7): 07001064
Author Affiliations
Abstract
School of Mathematics and Physics, University of Queensland, St Lucia, Queensland 4072, Australia
This article describes in detail a technique for modeling cavity optomechanical field sensors. A magnetic or electric field induces a spatially varying stress across the sensor, which then induces a force on mechanical eigenmodes of the system. The force on each oscillator can then be determined from an overlap integral between magnetostrictive stress and the corresponding eigenmode, with the optomechanical coupling strength determining the ultimate resolution with which this force can be detected. Furthermore, an optomechanical magnetic field sensor is compared to other magnetic field sensors in terms of sensitivity and potential for miniaturization. It is shown that an optomechanical sensor can potentially outperform state-of-the-art magnetometers of similar size, in particular other sensors based on a magnetostrictive mechanism.
Cavity optomechanics magnetic field sensors magnetostriction integrated microcavity Photonic Sensors
2012, 2(3): 259
