Microwave Detection With NV Color Centers Within 5 GHz Band

Microwave detection technology has important scientific and engineering application significance in wireless communication,remote sensing and precision measurement.The traditional microwave detection system is mainly composed of metal antenna and microwave circuit.The metal sensor is limited by high thermal noise,slow scanning and measurement speed,serious coupling and other problems,which seriously affect the microwave detection effect.At the same time,the limited space microwave detection system integration,precision,noise and other indicators put forward higher requirements.Therefore,it is urgent to develop new principles of microwave detection technology to achieve higher precision and more integrated microwave detection system design and measurement.Diamond Nitrogen Vacancy color center（NV）is a negatively charged point defect structure with advantages such as excellent optical characteristics,long spin life,initialization and readout of optical spin states,high temperature and high pressure resistance,easy integration of optical path structure and no electromagnetic interference to precision instruments.NV color center diamond sensor is very suitable for electromagnetic field high precision detection;Instead of conducting conventional metal microwave probes or SQUID superconducting quantum interference devices conducting serial point-by-point scanning methods,large area diamond imaging can quickly obtain microwave resonance field information in large areas.Improved system effectiveness.Therefore,this paper proposes the technique of microwave spectrum detection within 5GHz by using NV color center ensemble.The main innovations and work contents are as follows:（1）An optimization algorithm for real-time synchronous acquisition of multiple frames of differential images is designed to achieve a higher precision resonance frequency detection,reduce imaging frame errors,and achieve a high degree of synchronization between step and acquisition;At the same time,the multi-image synthesis weighted average algorithm is used to reduce the system noise and improve the detection sensitivity of the system.（2）A magnetic gradient amplification structure with T-shaped magnetic aggregation is proposed,which is used for magnetic field detection and the magnetic noise measurement of90 p T·Hz^-1/2 is realized.At the same time,the aggregation structure is applied to the gradient magnetic field structure,which realizes the optimal design of linear variation of magnetic field gradient in microwave field detection.（3）Using a diamond NV color center-based spectral microwave detection technology,a microwave detection platform based on magnetic aggregation amplification was built,and the spin-light detection of magnetic resonance effects using NV color center system synthesis was achieved with a microwave field spatial resolution of 1.5μm,an instantaneous bandwidth of70 MHz,a single wide-field imaging time of less than 1 s,and a detection frequency band of 5GHz.