Study On The THz Radiation-characteristics Of Photoconductive Antenna

It is Terahertz (THz) science and technology that was an issue widespreadconcerned worldwide. High-power, broadband THz radiation source was one ofthe determinants to limit the THz applications on various fields.Photoconductive antenna as THz source was the most simple and the mostwidely used method to produce high-power, broadband THz waves. Finitedifference time domain (FDTD) method combined with Drude-Lorentz model,Diffusion-Drift model were used based on Matlab software to numericalsimulate photoconductive antenna. The results provide a reference for designand manufacture of the high-power, broadband THz photoconductor antenna.Firstly, the physical nature of photoconductive antenna radiation THzwave and FDTD methodthe were analysised. The photoconductive antennaterahertz radiation simulation flow was studied. What’s more, the FDTD methodprogram was written. The program was agreed with the simulation result ofHFSS, which provided a right foundation for simulation THz radiationcharacteristics of the photoconductive antenna.Secondly, the simulation and experimental of photoconductive antennaradiation characteristics were studied. The material GaAs, photoconductiveantenna structure and the femtosecond laser excitation pulse were discussed. Inorder to further optimize the photoconductive antenna simulation method,Drude-Lorentz model and Diffusion-Drift model were comparative analysised.What’s more, two-valley effects and hot-carrier effects on photoconductiveantenna carrier transport were updated. The results show that the optimizedsimulation method was correct and feasible. The results also prove that thetwo-valley effects caused by the change of the carrier transport played a key roleon THz radiation; the hot-carrier effects was the main reason tend THz radiationelectric field to saturation. Optimization method and updated models simulationresults were more agree with terahertz time-domain spectroscopy (THz-TDS)system’s measurement results.Finally, numerical simulation software was written based on Matlab, which was used to provide a reference for the further effective simulationsoftware, and provide a reference for design and manufacture of the high-power,broadband THz photoconductive antenna.