Improving the efficiency of terahertz antennas on topological insulators

We study photoconductive antennas based on thin film of topological insulator and semiconductor heterostructure. A shift of the spectrum of a dipole antenna on a topological insulator to the long-wavelength region was found in comparison with a similar semiconductor antenna. Ways to increase the efficiency due to the deposition of plasmon gratings, as well as controlling the frequency response by changing the antenna impedance will be discussed.