Terahertz Fingerprint Detection Based On Microstructure Design

Terahertz(THz)detection technology has attracted worldwide interests,because of its low photonic energy and non-destructive characteristics.Compared with traditional technology,it can directly pass through the sample with or without the pretreatment steps,which makes it highly advantageous in the field of rapid detection.In addition,THz has extremely wide spectral range,covering the rotation and resonance frequencies of various complicated molecules,so THz technology has broad prospects in the field of sensing.Due to the limitations of the terahertz source and terahertz detection technology,the low sensitivity of terahertz detection,and the lack of information about chemical and biological molecules in the terahertz band make terahertz molecular sensing a great challenge,especially in the detection of trace-amount molecular.In this paper,a terahertz all-dielectric metagrating structure is proposed,which is used to enhance the terahertz wideband signal in molecular fingerprint detection.It has achieved the nondestructive terahertz fingerprint detection of trace-amount molecules.The conventional detection methods usually use the direct absorption of terahertz through a bare analyte sample.Unlike traditional detection methods,the all-dielectric metagrating enhances the wave-matter interaction and greatly increases the absorption signal of analyte.In addition,angle scanning method is dynamic to detect the broadband fingerprint of the analyte without the need for other complicated terahertz devices,and the combined multiplexed signals by angle scanning reflect the significant enhancement on broadband molecular fingerprint detection for identifying the trace-amount sample of 1?m thick.The excellent detecting performance for three analytes(?-lactose monohydrate,2,4-DNT and RDX)are investigated by electromagnetic full wave simulations based on the finite element method.The results of terahertz fingerprint detection of trace-amount molecules confirm that our proposed method provides a powerful tool for terahertz ultra-sensitive trace-amount analyte detection,and enables more possibilities for trace detection in the fields of defense,military and customs.