Preliminary Study On Key Technologies Of Chip-level Integration Of NV Magnetometer

In the quantum age of the 21st century,diamond nitrogen vacancy（NV）center has a broad application prospect in the field of micro and nano weak magnetic field detection due to its highly sensitive characteristics to magnetic field and excellent spatial resolution.These characteristics make NV sensor become a research hotspot in quantum sensor field in recent years.Based on the analysis of the design method and manufacturing process of the current mainstream integrated atomic magnetometer,aiming at the main problems facing the development of high integration and high sensitivity NV magnetometer,this paper develops a practical scheme for the fabrication of chip-level NV magnetometer by studying the key technologies of silicon based near-field magnetic dipole antenna and convex polyhedral diamond with efficient fluorescence collection.Specific research contents are as follows:（1）With the goal of integrated design,we design a silicon-based near-field magnetic dipole antenna.We established an antenna model in HFSS,and achieved a relatively uniform magnetic field strength in the near field range of the antenna by optimizing the ring antenna spacing,moreover,diamond can be embedded in the substrate of this antenna,which reduces the distance between the diamond NV center and the metal radiation layer of the antenna.When the output power of the microwave source is 0d Bm,the maximum radiation intensity of the antenna near field is-35dbm measured by the spectrum analyzer.On the established optical platform,we completed the detection of spin resonance signals at the output power of the microwave source at-5d Bm.（2）Aiming at the problem of low laser-collection fluorescence conversion efficiency in the current highly integrated NV magnetometer,we design a convex polyhedral diamond structure with optimized sidewall dip Angle.With this structure,the maximum collection efficiency is estimated to be approximately 40%without the introduction of any optical lens to assist fluorescence collection,and the laser-collection fluorescence conversion efficiency of the diamond after laser cutting and polishing can reach 3.7%.（3）Finally,we embed the diamond inside the silicon-based antenna to realize the three-dimensional stacking assembly of the integrated silicon-based antenna,convex polyhedral diamond,filter,and Photo-Diode（PD）.The overall size of the assembled device is limited to8.5×7×3 mm³,and it achieves a laser-collection fluorescence conversion efficiency of 2.4%,and achieves a system sensitivity of 9 n T/Hz^1/2 and a shot noise of 0.4 n T/Hz^1/2 under 80m W laser irradiation.Through the preliminary research of key technologies such as miniaturized silicon-based antennas and diamond structure with efficient fluorescence collection,and three-dimensional stacking assembly,this paper provides a theoretical analysis and experimental processing basis for the future development of high-performance NV magnetometer chip-based integration.