Generation and detection of terahertz radiation using photoconductive semiconductor antennas based on LT-In$_x$Ga$_{1-x}$N/GaN

A material in the form of a multilayer structure based on LT-GaN grown on Al$_2$O$_3$ sapphire substrates with a crystallographic direction (0001) is proposed for the manufacture of terahertz photoconductive antennas. The structures contain active layers of In$_x$Ga$_{1-x}$N/GaN. The mole fraction In in the In$_x$Ga$_{1-x}$N quantum well region is chosen to be 0.32. At an optical pumping power of 57 MW and a bias voltage of 15 V a photoconductive antenna on an optimized LT-In$_x$Ga$_{1-x}$N/GaN structure emits terahertz pulses with an average power of 4.5 $\mu$W at a laser pulse repetition rate of 60 MHz. Time profiles and frequency spectra of Fourier amplitudes of terahertz pulses generated using LT-GaN-based antennas have been obtained.