金刚石NV色心磁力仪测磁性能优化

Optimization of magnetic properties measured by diamond nitrogen-vacancy color-centered magnetometer

金刚石NV色心以其高磁场灵敏度、常温工作等优势成为一种非常有前景的磁场传感器。本文介绍了NV色心测磁原理,设计并搭建了基于NV色心的磁测量系统,通过激光-荧光差分光路将噪声降低至约1/8,使用微波混频调制方法将ODMR谱线斜率提升2.5倍左右,最终基于NV色心浓度<300 ppb的金刚石样品实现了0.934 nT/Hz^(1/2)的磁场测量灵敏度。同时设计了基于双微波调制解调的NV测磁系统,并在10 kHz采样率下实现了1.76×10^(-4)的测量不确定度,基于阿伦方差分析方法,在0.2 s统计时间条件下测量不确定度达到10 ppm。

The diamond nitrogen-vacancy center has become a very promising magnetic field sensor with its advantages of high sensitivity,sensitivity to external magnetic field,and detectability at room temperature.In this paper,we introduce the principle of magnetic measurement by nitrogen-vacancy center,and a magnetic measurement system based on nitrogen-vacancy center is designed and constructed,in which the noise is reduced to about 1/8 by the laser-fluorescence differential optical path,and the microwave mixing modulation method can enhance the slope of the ODMR spectral line by about 2.5 times,and the sensitivity of magnetic field measurement of 0.934 nT/Hz^(1/2)is finally realized based on the diamond samples with the concentration of nitrogen-vacancy center<300 ppb.Meanwhile,the NV magnetometry system based on dual microwave modulation and demodulation was designed,and a measurement uncertainty of 1.76×10^(-4)was achieved at a sampling rate of 10 kHz,and a measurement uncertainty of 10 ppm was achieved at a statistical time of 0.2 s based on the Allen variance method.