Effects of Microwave and Laser Power on Optical Detection Magnetic Resonance of Diamond Nitrogen Vacancy Center

Using continuous wave optical detection magnetic resonance (ODMR), diamond nitrogen-vacancy (NV) center has been widely used in magnetic field measurement at the experimental stage. Microwave and laser power have significant influence on the sensitivity of magnetic field measurement. A set of confocal magnetic field detection system based on the ensemble of NV center is established. By adjusting the microwave and laser power, it is observed that the contrast and the full width at half maximum (FWHM) of the ODMR spectra change obviously. The experiment indicates that the contrast has a maximum value under the change of microwave and laser power, while the FWHM is mainly dominated by microwave power at low light intensity. Adjusting the microwave power to obtain an applicable FWHM, then reducing the laser power appropriately, the light narrowing phenomenon could be observed, and the operation above could improve the sensitivity of magnetic field measurement effectively.