用于悬浮光力系统的低噪声四象限探测器研究  

A Low-Noise Quadrant Photodetector for Levitated Optomechanical Systems

作　　者：王颖颖 何沛彤 梁韬 高晓文 蒋静 陈杏藩[2] 胡慧珠 Wang Yingying;He Peitong;Liang Tao;Gao Xiaowen;Jiang Jing;Chen Xingfan;Hu Huizhu(Research Center for Quantum Sensing,Zhejiang Lab,Hangzhou 310023,Zhejiang,China;College of Optical Science and Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China)

机构地区：[1]之江实验室量子传感研究中心,浙江杭州310023 [2]浙江大学光电科学与工程学院,浙江杭州310027

出　　处：《光学学报》2023年第11期1-8,共8页Acta Optica Sinica

基　　金：国家自然科学基金面上项目(62075193);之江实验室科研攻关重大项目(2019MB0AD01);之江实验室自立创新项目(2021MB0AL02)。

摘　　要：悬浮光力系统由于其出色的探测性能,已成为精密测量领域的研究热点。目前悬浮光力系统的探测方案主要包括平衡探测器方案和四象限探测器方案。平衡探测器噪声性能优越,但单个探测器只能测量一个方向的悬浮微粒位移信息,探测系统复杂。四象限探测器方案仅使用单个探测器即可同时探测微粒的三轴位移信息,探测系统简单,但噪声性能较差。本文根据悬浮光力系统的需求,设计了一种四象限探测器,实现了105量级跨阻增益,电学噪声达到商用平衡探测器水平,共模抑制比优于45 d B(50~250 k Hz),且入射光功率大于1 m W时,噪声性能只受散粒噪声限制。实验表明,该四象限探测器方案可替代平衡探测器方案,使探测系统小型化,并能很好地满足高探测灵敏度的需求。Objective Due to the excellent detection performance,levitated optomechanical systems have become intriguing in the field of precision measurement.The detection schemes of such systems mainly contain the balanced photodetector(BPD)and quadrant photodetector(QPD).The BPD has a current differential structure that can eliminate commonmode DC signals,which results in extra low noise.However,the BPD scheme has the disadvantage of complicated detection systems because one BPD usually measures the particle displacement in one direction.In contrast,a QPD can simultaneously detect displacements in three directions,which effectively simplifies the detection system.Usually,QPDs amplify not only the AC photocurrent generated by the fluctuations of the incident optical power,which mainly arise from the displacements to be measured,but also the DC photocurrent corresponding to the average incident optical power.As a consequence,QPDs always show worse noise performance than BPDs.Therefore,this work proposes a QPD scheme,which reduces the electrical noise of a QPD through electrical filtering and achieves a commonmode rejection ratio(CMRR)as high as possible,and the response coefficients of the four quadrants are calibrated.The QPD is a promising alternative scheme to the BPD,which has high detection sensitivity and is beneficial to the miniaturization of levitated optomechanical systems.Methods This work proposes a QPD scheme by building the noise model in levitated optomechanical systems,according to which the proportions of electrical noise,optical shot noise,and relative intensity noise(RIN)can be obtained.A current filter circuit is built with an operational amplifier,and the DC and AC components of the photocurrent are separated without any influence on the junction capacitance of the QPD sensor.As a result,the AC transimpedance gain is free from the limitation of the DC component,and meanwhile,the electrical noise is reduced.The converted voltage signal from the AC component is used to demodulate the threeaxis displacemen

关 键 词：探测器 光电探测器 悬浮光力系统 噪声分解 共模抑制 

分 类 号：TN29[电子电信—物理电子学]