Study On Asymmetric Transmission And Tunable Absorber Devices Based On Dirac Semimetal Films

In recent years,with the rapid development of terahertz technology,terahertz waves have shown great application potential in the field of imaging,communication,sensing,and security monitoring.However,the lack of effective materials greatly limits the depth development of terahertz technology to various functional optical devices and hinders the practical application progress of terahertz technology.Due to the unique electromagnetic characteristics of metamaterials in the terahertz band,it has become an ideal material for the development of terahertz devices,which brings new opportunities for the development of new terahertz devices.In this paper,asymmetric transmission and absorber functional devices are studied based on Dirac semimetal films metamaterial.The main research contents of the paper are summarized as follows:1.The asymmetric transmission device based on Dirac semimetal films metamaterial is studied.This device can realize the function of polarization conversion and asymmetric transmission of linearly polarized wave in THz frequency domain.In the range of 5.5-6.0THz,the asymmetric transmission parameter of linearly polarized wave?0.6,and the asymmetric transmission parameter of circularly polarized wave is close to 0 in the frequency range of 4.0-7.5THz,which shows that the structure can achieve asymmetric transmission of linearly polarization,but cannot achieve asymmetric transmission of circularly polarized waves.The influences of structural parameters on asymmetric transmission parameters were studied and the influences of Fermi energy level of Dirac semimetal films metamaterial on polarization conversion rate,total transmission and asymmetric transmission parameters were studied,Thus the dynamic tuning of polarization conversion band was realized.2.The absorber device based on Dirac semimetal films metamaterials is studied,and established three different unit cell structures of absorber.The research results show that the multi-frequency absorber can reach 100%absorption under normal incidence.The independent tunable of the absorption peak can be achieved by changing the structural parameters.The dynamically tunable can be realized by changing the Fermi energy level of Dirac semimetal films.The proposed absorber provides guidance for the design of tunable absorbers and is of great significance for the design of frequency-selective detectors in future sensing applications.