摘要
场矢量探测是量子精密测量的重要分支,在基础物理、生物医学、材料科学等领域,都有着广泛的应用。金刚石氮-空穴(Nitrogen-Vacancy Center)色心作为量子传感器,在室温下具有较长相干时间,可以实现纳米尺度的磁场探测。为了实现纳米分辨率的磁场重构,需要选取金刚石中三个不同轴向的NV色心作为磁场传感器。实验上能否快速和精确地获得NV色心的轴向信息直接决定着矢量磁场测量的精度和效率。本文利用角向偏振光束代替高斯光束激发NV色心获得其扫描荧光图像,结合卷积神经网络对NV色心的荧光图像进行识别,提出了一种基于图像匹配的NV色心拟合优化算法,在梯度下降算法上结合图像识别处理和匹配算法,优化了NV色心轴向信息的提取过程,提高了拟合的速度和准确率,进而增加了磁场矢量重构的效率。
Vector magnetometer is an important branch of quantum precision measurement,which has been widely used in basic physics,biomedicine,material science and other fields.As a quantum sensor,the Nitrogen-Vacancy Center has a longer coherency time at room temperature,allowing for nanoscale magnetic field detection.Three different coaxial NV centers of diamond should be selected as magnetic field sensors to realize the reconstruction of vector magnetic field with nanometer resolution.Whether the axial information of NV center can be obtained quickly and accurately directly affects the accuracy and efficiency of vector magnetic field measurement.Therefore,how to obtain the axial information of the NV center is influential.This paper proposes a confocal microscopy imaging system based on machine learning fitting method,combined with an angularly polarized beam instead of a Gaussian beam to excite the NV center to obtain a scanning fluorescence image.Then the identification of the diamond NV center axis and the problem of calculating the azimuth and polar angle of the NV axis in space are solved through the method.This article demonstrates a model based on convolutional neural network to automatically identify and locate NV centers in diamond,and on the basis of object detection,the method of gradient descent fitting is combined with image recognition processing and matching algorithms.The model accelerates extraction of the axial information of the four NV axes,optimizes the extraction process of the NV center axial information,improves the speed and accuracy of fitting,and thereby increases the efficiency of magnetic field vector reconstruction.The research results of this design can be applied to the measurement of the magnetic field vector,and not only can it improve the calculation efficiency of the NV center angle direction in the diamond,but also has a degree of robustness to the noise in the experimental environment.
作者
张小涵
刘玉山
李桢旻
ZHANG Xiao-han;LIU Yu-shan;LI Zhen-mint(School of Electronic Science and Applied Physics,Hefei University of Technology,Hefei 230009 China)
出处
《量子光学学报》
北大核心
2021年第2期148-156,共9页
Journal of Quantum Optics
关键词
金刚石氮-空穴色心
回程差消除
图像匹配
目标检测
色心轴向识别
nitrogen-vacancy center
elimination of backhaul difference
image matching
object detection
axial recognition
