Research On Sensing Of Non-hermitian Spoof Surface Plasmon Polariton

In recent years,research has shown that exceptional points in non-Hermitian system can provide higher sensitivity and show great application prospect in sensor field.However,due to the limitation of processing technology,it is still difficult to realize singularity in sub-wavelength structure.On the other hand,localized surface plasmon resonance of nanoparticles can produce a great electromagnetic enhancement effect near the nanoparticles.It has a wide range of applications in the field of sensing.In this thesis the advantages of the two sensors in size and sensitivity are combined to design a new type of microwave sensor with high sensitivity and miniaturization.On this basis,the ability of sensing metal particles,micro-liquids and chiral units is further investigated.Through theoretical model,numerical simulation and experimental verification,it is proved that the new sensor can effectively improve the sensitivity of the sensor and break through the detection limit of micro-samples.This opens up new possibilities for subwavelength sensors in the microwave,terahertz radiation and even the far infrared.The main work contents are as follows:1.A novel sensor structure based on non-Hermitian spoof surface plasmon polariton is proposed.The non-Hermitian resonant element is constructed by constructing two extended teeth on the edge of the periodically slotted metal disk,and the system is optimized to singular point by the position and size of the extended teeth.2.The sensing effect of the new sensor on metal particles and liquids was investigated.For metallic particles,the EP sensor can reduce the detection limit to 1/100 wavelength.Compared with the traditional method,the new sensor has higher sensitivity to small metal particles.In the aspect of liquid sensing,the new sensor can detect the refractive index of 0.72 μL micro-liquid.3.Based on the sensitivity of the new sensor to chiral disturbances,the detection ability of circular dichroism of the sensor is proved.The small chiral helices can be detected,and the asymmetry factor is much larger than that of traditional sensors.