Microwave power self-coherent reference measurement based on ensembles of nitrogen-vacancy centers in diamond

Microwave detection based on optical detection magnetic resonance technology (ODMR) of nitrogen-vacancy (NV) centers is simple and non-invasive. However, in high microwave power ranges, saturation appears and cannot be used for accurate power measurement. The self-coherent reference measurement for high-power microwave based on ODMR of NV centers has been demonstrated. Firstly, by introducing the principle of microwave self-coherent reference, that is, by adjusting the phase difference to achieve power regulation of microwave, a conversion model by phase modulation between enhancement and attenuation of microwave power is introduced. Then, the microwave self-coherent reference measurement is established under combinations of microwave power with different phase settings. Combined with the frequency modulation technology, the sensitivity of measurement is significantly improved from 4.59 nT/Hz