Simulation analysis of radiation terahertz wave characteristics of photoconductive antenna materials
The photoconductive antenna is a kind of widely used broadband terahertz(THz)radiation source in THz time-domain spectroscopy systems,and the substrate material of the antenna is crucial for the characteristics of generat-ed THz wave.The widely used photoconductive antenna material is the second-generation semiconductor of GaAs,while the third-generation semiconductor has a larger band gap,which is more advantageous for improving the power of THz wave from photoconductive antenna.In this work,the current surge model of large-aperture photoconductive an-tennas was used to simulate the characteristics of THz waves radiated by the photoconductive antenna made from com-monly used SI-GaAs and LT-GaAs,and the third-generation semiconductors(ZnSe,GaN,SiC)that are expected to be used in the future for photoconductive antennas.The results show that under the same bias electric field and their respec-tive highest pump laser flux,LT-GaAs antenna generates THz waves with the highest amplitude and widest frequency.The photoconductive antenna made by the third-generation semiconductor materials can withstand higher bias electric fields,and the intensity of radiated THz waves is much greater than that from GaAs antennas under their respective max-imum bias electrical fields.This work provides theoretical guidance for the development of new third-generation semi-conductor photoconductive antennas.
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