Adaptive Sweep Excitation of Optical Detection Magnetic Resonance Method for Measuring Magnetic Field in Diamond NV Center

Precise magnetic field measurement by using diamond nitrogen-vacancy (NV) center is a hot research direction in quantum detection field. At present, a main measurement method is continuous wave optical detection magnetic resonance (CW-ODMR). To obtain the complete ODMR curve required by this method, all frequency microwaves are needed to be traversed in a wide frequency band. However, in the subsequent calculation of the actual magnetic field, only a few narrow ODMR curves carry effective magnetic field information, and most of the frequency band curves brought by noise are meaningless. Using the traditional CW-ODMR method, each sweep point in the frequency band needs to use the scientific grade complementary metal oxide semiconductor (s-CMOS) camera to collect data, and there are a large amount of data and high computational complexity. In this paper, an adaptive sampling method with sweep step length is proposed. The identification thresholds of noise interval and signal interval are set, and their step conversion algorithms are used in different intervals. The adaptive step length sampling is used to replace the drawing of complete ODMR curve. The final simulation experiment shows that the method in this paper greatly reduces the number of frequency sweep points under the premise of ensuring the accuracy of magnetic field measurement.