Multifunction tunable broadband terahertz device for polarization rotation and linear asymmetric transmission based on Dirac semimetals

摘要

A three-layer complementary strip Dirac semimetal polarizer is proposed to achieve polarization rotation, perfect polarization conversion, and asymmetric transmission. This device can realize broadband polarization operation of linear polarized waves in the terahertz frequency domain. By changing the Fermi level of the Dirac semimetal, the polarization angle of linearly polarized light in the frequency range of 1.3 to 1.63 THz can be rotated from 0 degrees to 90 degrees, and the device has good robustness for linearly polarized light with different incident angles. When used as an asymmetric transmission device, its polarization conversion efficiency reaches more than 98% and the asymmetric transmission parameter reaches more than 50% in the range of 1.3-1.63 THz. The asymmetric transmission parameters, polarization conversion ratio, polarization rotation angle, and ellipticity are used to describe the performance of the converter.