The Tunable Terahertz Detector Based On A Composite Resonator

Terahertz technology is widely used in deep space exploration,security imaging and quality monitoring,and it plays an important role not only in national defense military but also industrial production.The terahertz detector consists of an antenna substrate and a device for sensing terahertz radiation.Electromagnetic metamaterial is a periodically arranged sub-wavelength structure,and its electromagnetic characteristics are related to structure distribution and period size.Combining with the characteristics of the flexible control of electromagnetic waves by metamaterial arrays,this paper systematically studies a tunable terahertz detector based on a composite resonant cavity through electromagnetic simulation and experimental measuring.The main achievements in scientific research of this paper are as follows:First,based on the electromagnetic simulation software,the composite resonant cavity structure composed of the metamaterial structure,the detector substrate and the back mirror is simulated and calculated,and a set of optimized structural parameters of the metamaterials were obtained.The calculation results show that by changing the interval length of the air cavity,the resonant frequency of the composite resonator is continuously adjustable from 0.6372 THz to 0.6759 THz.The composite structure is further applied to the terahertz detector.The simulation results show that due to the multi-resonant cavity effect,the interaction of metamaterials and the terahertz planar antenna,the composite structure has multi-resonance phenomenon.We used the interference theory to carry out detailed Explanation.Second,according to the designed composite resonant cavity structure,a hexanitrogen pentaniobium terahertz detector based on the structure was developed,and a test and characterization system for a movable composite resonant cavity was built,and the response voltage of the terahertz detector was measured.The experimental conclusion show that the resonant frequency of the terahertz detector can be adjusted by adjusting the interval length of the air cavity in the composite resonant cavity structure.When the interval length of the air cavity increases,the resonant frequency moves in the lower frequency direction,which is consistent with the design simulation results.