Research Of EIT And Fingerprint Sensing Based On Spoof Surface Plasmon Polaritions With Terahertz Antenna Structure

Due to its low energy level,high spectral resolution,penetrating and other properties,terahertz waves(THz)have important applications in safety inspection,biochemical preparation,quality control,medical diagnosis and pharmaceutical synthesis in recent years.The theory of supporting spoof surface waves by etching a one-dimensional array of grooves on a metal surface has been proposed for ages.Still,the applications in the terahertz band are few,especially for the design and manufacturing of various terahertz devices.Recently,a novel comb-shaped planar antenna structure has been proposed,which not only supports the spoof surface plasma mode but also has strong field constraint and field enhancement effects.In this paper,we designed and studied different antenna structures to achieve the EIT effect in the terahertz band based on the scattering field interference cancellation and realize high-sensitivity fingerprint characteristic detection in the terahertz band.The research on the antenna structure expands the application research of the terahertz functional devices based on spoof surface plasma.The main work of this paper is:(1)The dispersion characteristics are analyzed and introduced,indicating this antenna structure can nicely support spoof surface plasma.Based on previous studies,the optical characteristics of the planar antenna structure are also present,indicating the application prospects for EIT and THz fingerprint sensing,and the fabrication and performance testing of spoof surface plasmon antenna structure are also given.(2)The planar antenna structure supporting the spoof surface plasma mode is designed to produce the EIT effect similar to the interference cancellation in the atomic system,which has not been studied in detail.The finite element method(FEM)is used to simulate the optical characteristics.The structure is fabricated by laser direct writing,thermal evaporation,metal stripping,etc.,and the results of the THz-TDs transmittance test well verify the EIT effect of this novel structure,promoting the development of application research on THz functional devices.(3)A novel terahertz fingerprint sensor based on spoof surface plasmon antenna structure is proposed.The sensor consists of a three-slot planar antenna array structure and a silicon substrate,and lactose is used as a substance to be tested to demonstrate the fingerprint sensing performance of this sensor.By simulating the structure by FEM,we know that the fingerprint sensing signals for lactose in the transmission and reflection modes are improved by 7.6 times and 13 times respectively,indicating this sensor can achieve high sensitivity detection.In addition,the quantitative detection performance of this sensor was analyzed,the results indicate that the sensor can not only achieve qualitative detection but also quantitative detection.