Tunable Asymmetric Transmission in Bulk Dirac Semimetal Based Terahertz Metamaterial

Chiral metamaterial (CMTM) with non-superimposable patterns have made it possible to realize asymmetric transmission (AT) phenomenon, where the polarization conversion (transverse electric (TE) to transverse magnetic (TM) or vice versa) is not same for the forward and the backward excitations of linearly polarized electromagnetic waves. In this work, we demonstrate the possibility of tunable asymmetric transmission using bulk Dirac semimetal (BDS) based metamaterial at terahertz (THz) frequencies. The designed BDS CMTM is numerically solved for the frequency range 0.9THz to 1.7THz and a broadband AT of 24.8% is achieved. While varying the E
f
from 0.09eV to 0.15eV, 30.23% tunability is observed in the AT response of BDS CMTM. Even though the experimental realization of BDS-based THz metamaterials is cumbersome at this time, the tunable AT response suggests the possibility ofTHz wave modulation accompanied by polarization conversion and switching functionalities.