Picotesla-sensitivity microcavity optomechanical magnetometry

Fuente: arXiv
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Main Authors: Hu, Zhi-Gang, Gao, Yi-Meng, Liu, Jian-Fei, Yang, Hao, Wang, Min, Lei, Yuechen, Zhou, Xin, Li, Jincheng, Cao, Xuening, Liang, Jinjing, Hu, Chao-Qun, Li, Zhilin, Lau, Yong-Chang, Cai, Jian-Wang, Li, Bei-Bei
Format: Preprint
Published: 2024
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author Hu, Zhi-Gang
Gao, Yi-Meng
Liu, Jian-Fei
Yang, Hao
Wang, Min
Lei, Yuechen
Zhou, Xin
Li, Jincheng
Cao, Xuening
Liang, Jinjing
Hu, Chao-Qun
Li, Zhilin
Lau, Yong-Chang
Cai, Jian-Wang
Li, Bei-Bei
author_facet Hu, Zhi-Gang
Gao, Yi-Meng
Liu, Jian-Fei
Yang, Hao
Wang, Min
Lei, Yuechen
Zhou, Xin
Li, Jincheng
Cao, Xuening
Liang, Jinjing
Hu, Chao-Qun
Li, Zhilin
Lau, Yong-Chang
Cai, Jian-Wang
Li, Bei-Bei
contents Cavity optomechanical systems have enabled precision sensing of magnetic fields, by leveraging the optical resonance-enhanced readout and mechanical resonance-enhanced response. Previous studies have successfully achieved scalable and reproducible microcavity optomechanical magnetometry (MCOM) by incorporating Terfenol-D thin films into high-quality ($Q$) factor whispering gallery mode (WGM) microcavities. However, the sensitivity was limited to 585 pT/Hz$^{1/2}$, over 20 times inferior to those using Terfenol-D particles. In this work, we propose and demonstrate a high-sensitivity and scalable MCOM approach by sputtering a FeGaB thin film onto a high-$Q$ SiO$_2$ WGM microdisk. Theoretical studies are conducted to explore the magnetic actuation constant and noise-limited sensitivity by varying the parameters of the FeGaB film and SiO$_2$ microdisk. Multiple magnetometers with different radii are fabricated and characterized. By utilizing a microdisk with a radius of 355 $μ$m and a thickness of 1 $μ$m, along with a FeGaB film with a radius of 330 $μ$m and a thickness of 1.3 $μ$m, we have achieved a remarkable peak sensitivity of 1.68 pT/Hz$^{1/2}$ at 9.52 MHz. This represents a significant improvement of over two orders of magnitude compared with previous studies employing sputtered Terfenol-D film. Notably, the magnetometer operates without a bias magnetic field, thanks to the remarkable soft magnetic properties of the FeGaB film. Furthermore, as a proof-of-concept, we have demonstrated the real-time measurement of a pulsed magnetic field simulating the corona current in a high-voltage transmission line using our developed magnetometer. These high-sensitivity magnetometers hold great potential for various applications, such as magnetic induction tomography and corona current monitoring.
format Preprint
id arxiv_https___arxiv_org_abs_2403_14301
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Picotesla-sensitivity microcavity optomechanical magnetometry
Hu, Zhi-Gang
Gao, Yi-Meng
Liu, Jian-Fei
Yang, Hao
Wang, Min
Lei, Yuechen
Zhou, Xin
Li, Jincheng
Cao, Xuening
Liang, Jinjing
Hu, Chao-Qun
Li, Zhilin
Lau, Yong-Chang
Cai, Jian-Wang
Li, Bei-Bei
Optics
Applied Physics
Cavity optomechanical systems have enabled precision sensing of magnetic fields, by leveraging the optical resonance-enhanced readout and mechanical resonance-enhanced response. Previous studies have successfully achieved scalable and reproducible microcavity optomechanical magnetometry (MCOM) by incorporating Terfenol-D thin films into high-quality ($Q$) factor whispering gallery mode (WGM) microcavities. However, the sensitivity was limited to 585 pT/Hz$^{1/2}$, over 20 times inferior to those using Terfenol-D particles. In this work, we propose and demonstrate a high-sensitivity and scalable MCOM approach by sputtering a FeGaB thin film onto a high-$Q$ SiO$_2$ WGM microdisk. Theoretical studies are conducted to explore the magnetic actuation constant and noise-limited sensitivity by varying the parameters of the FeGaB film and SiO$_2$ microdisk. Multiple magnetometers with different radii are fabricated and characterized. By utilizing a microdisk with a radius of 355 $μ$m and a thickness of 1 $μ$m, along with a FeGaB film with a radius of 330 $μ$m and a thickness of 1.3 $μ$m, we have achieved a remarkable peak sensitivity of 1.68 pT/Hz$^{1/2}$ at 9.52 MHz. This represents a significant improvement of over two orders of magnitude compared with previous studies employing sputtered Terfenol-D film. Notably, the magnetometer operates without a bias magnetic field, thanks to the remarkable soft magnetic properties of the FeGaB film. Furthermore, as a proof-of-concept, we have demonstrated the real-time measurement of a pulsed magnetic field simulating the corona current in a high-voltage transmission line using our developed magnetometer. These high-sensitivity magnetometers hold great potential for various applications, such as magnetic induction tomography and corona current monitoring.
title Picotesla-sensitivity microcavity optomechanical magnetometry
topic Optics
Applied Physics
url https://arxiv.org/abs/2403.14301