Picotesla-sensitivity microcavity optomechanical magnetometry  

作　　者：Zhi-Gang Hu Yi-Meng Gao Jian-Fei Liu Hao Yang Min Wang Yuechen Lei Xin Zhou Jincheng Li Xuening Cao Jinjing Liang Chao-Qun Hu Zhilin Li Yong-Chang Lau Jian-Wang Cai Bei-Bei Li 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]School of Physics,Beihang University,Beijing 100191,China [4]Songshan Lake Materials Laboratory,Dongguan 523808 Guangdong,China

出　　处：《Light(Science & Applications)》2024年第11期2835-2846,共12页光（科学与应用)（英文版）

基　　金：funding from the National Key Research and Development Program of China(2021YFA1400700,2021YFB3501400);National Natural Science Foundation of China(NSFC)(62222515,12174438,11934019,12274438);Innovation Program for Quantum Science and Technology(2023ZD0301100);Basic frontier science research program of Chinese Academy of Sciences(ZDBS-LY-JSC003);CAS Project for Young Scientists in Basic Research(YSBR-100);Z.L.is grateful for the support from the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2021008);supported by the Micro/nano Fabrication Laboratory of Synergetic Extreme Condition User Facility(SECUF).

摘　　要：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 mass-produced 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 mass-produced MCOM approach by sputtering a FeGaB thin film onto a high-Q SiO2 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 SiO2 microdisk.Multiple magnetometers with different radii are fabricated and characterized.By utilizing a microdisk with a radius of 355μm and a thickness of 1μm,along with a FeGaB film with a radius of 330μm and a thickness of 1.3μm,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.

关 键 词：PARTICLES MAGNETOMETER FILM 

分 类 号：TN2[电子电信—物理电子学] O4[理学—物理]