双螺线圈射频共振结构增强硅空位自旋传感灵敏度方法

Methodology of improving sensitivity of silicon vacancyspin-based sensors based on double spiral coil RFresonance structure

针对硅空位自旋磁共振信号射频场非均匀展宽问题,提出并设计了一种双螺线圈射频共振结构,利用双螺线圈平行对称特性,构建射频场均匀区,非均匀性小于0.9%,相比单根直线性结构,均匀性提高了56.889倍.同时,利用射频信号近距离互感耦合共振特性,实现了射频场的增强,相比单线圈结构增强了1.587倍,等效的自旋传感灵敏度提高了4.833倍.实验中搭建基于SiC硅色心自旋磁共振效应的光探测磁共振传感测量系统,通过对比不同类型的射频天线,测试得到基于双螺线圈射频共振天线结构的硅空位色心自旋磁共振信号对比度提高了6倍,通过调制解调信息解算方法得到传感器的灵敏度提高了4.833倍,传感器噪声降低了8倍,提高了硅空位自旋传感测量灵敏度,结合SiC晶圆芯片制造技术,为高精度、芯片级自旋量子传感器件的制造提供了技术支撑.

Due to the power instability and field non-uniformity of radio frequency(RF),microwave(MW)and laser signals,inhomogeneous broadening of spin magnetic resonance line causes the absorption to decrease in a nuclear resonance system,which can reduce the sensitivity of spin-based sensing and testing technology.In this paper,we propose and design a double solenoid coil RF resonance antenna structure.The nearly uniform RF field density is produced by the two solenoid coil antenna structures that are parallel to the symmetry axis.The size of the uniformity in the center region of double solenoid coil RF resonance antenna structure is aboutπ×375 mm2×10 mm.And the non-uniformity is less than 0.9%.Comparing with a single straight wire antenna and the single solenoid coil RF resonance antenna structure,the uniformity is improved by about 56.889 times and 42.889 times,respectively.At the same time,based on the near-field mutual inductance coupled resonance effect,the intensities of RF field in the center region of the two-solenoid coil antenna structure is enhanced.Comparing with the single solenoid coil antenna structures,it is enhanced by about 1.587 times.And the equivalent sensitivity of the silicon vacancy color center spin based sensor is enhanced by about 4.833 times.In the experiment,an optical detection magnetic resonance measurement system based on the spin magnetic resonance effect of silicon vacancy color center in single crystal SiC is built.Comparing with the single straight wire antenna and the single solenoid coil RF resonance antenna structure,the contrast of the silicon vacancy color center spin magnetic resonance signals of the double solenoid coil RF resonance antenna structure increases about 6 times and 2.4 times,respectively.The sensitivity of the spin-based sensor is increased by 4.833 times and 2.071 times through using the modulation and demodulation method,and the noise decreases by 8 times and twice.Hence,based on this double solenoid coil RF resonance antenna structure,the sensitivity of the silicon vacancy spin sensor can be improved.Combined with chip manufacturing technology of SiC wafer,it proves to be a potential approach to developing the high precision,chip scale spin sensor devices and measurement technology.