Design of a tunable multichannel terahertz absorber in one-dimensional photonic crystals incorporating a Dirac semimetal-dielectric defect layer

This paper presents a multichannel terahertz absorber designed using an asymmetric one-dimensional photonic crystal featuring a defect composed of dielectric-bulk Dirac semimetal. The absorption properties of the proposed structure are theoretically analyzed by examining various configurations of the defect layer in terahertz frequency region for both transverse magnetic and transverse electric polarizations. We investigate the tuning properties of the absorption channels by varying the Fermi energy of the Dirac semimetal and the angle of incident light for different configurations. The results demonstrate that changes in the Fermi energy and incident angle significantly influence both the frequency and peak value of the absorption channels. Furthermore, the number of absorption channels increases with the addition of bulk Dirac semimetal layers in the defect region.