Tunable terahertz Bloch surface waves in one-dimensional photonic crystals with a Dirac semimetal cap layer

Abstract

The dispersion relation and localization of surface waves in semi-infinite one-dimensional photonic crystals in the presence of Dirac semimetal as a cap layer are theoretically and numerically investigated, using the transfer matrix method at terahertz band. It is demonstrated that the frequency and localization of surface waves can be tuned by changing the cap layer's Fermi energy for both transverse electric and transverse magnetic polarizations. The numerical results show that the dispersion relation of surface waves and consequently their localization are more sensitive to changes in Fermi energy. Therefore, the surface states with the desired localization can be achieved. In addition, the effect of the cap layer's thickness and the arrangement of the photonic crystal layers on surface waves are investigated. The results show that these parameters have considerable effect on modification of surface waves.