Research On High Performance Terahertz Polarizer With Au Wire-grid Structure

Terahertz(THz)wave refers to the electromagnetic waves that frequency in the 0.1-10 THz range.The THz polarizer is one of the key components of THz system,which direct influences the application of THz technology in detection,communication,astronomy and biomedical detection technologies.This paper focus on the optimization of Au wire-grid structure THz polarizer.The theoretical simulation and experimental processing has been performed to process the new type THz polarizer with double bilayer Au wire-grid structure.The main contents are as follows.1.The CST STUDIO is used to simulate the model of Au wire-grid structure THz polarizer.The detail analysis of performance for monolayer,single-bilayer and double-bilayer structure with different parameters has been done.The results confirmed that double-bilayer structure can get high extinction ratio and the extinction ratio was close to 4 times than monolayer structure.2.The micro-nanofabrication process about Au wire-grid structure THz polarizer has been optimized.The silicon nitride layer has been deposited on the silicon substrate to avoid the Au adhere on the etched sidewalls of silicon.This method can improve the extinction ratio of THz polarizer with double bilayer Au wire-grid structure.The good quality double-bilayer Au wire-grid structure THz polarizer has been realization with the period as 4 um,line width as 2 um and etching depth as 1um.3.The polarizer's performances has been characterized by terahertz time-domain spectroscopy(THz-TDS).The results shown that the double-bilayer Au wire-grid structure THz polarizer was average 60 dB extinction ratio(maximum 87 dB)with low insertion loss in the range of 0.5-2.0 THz.In this paper,we research the double-bilayer Au wire-grid structure THz polarizer with theoretical simulation and experimental processing,it will provides an important reference for the optimization of THz system.