Terahertz emission and reflection associated with surface plasmon polaritons in n-GaN microstructures

Surface plasmon polaritons at the n-GaN/vacuum interface are investigated. Experimental studies of terahertz radiation reflection and emission are performed on heavily silicon-doped GaN epitaxial layers grown on sapphire substrates. To provide interaction of THz radiation with the surface plasmon polaritons, a regular grating was fabricated on the outer surface of the epitaxial layer. Study of terahertz radiation emission from the microstructures under lateral electric field shows that the scattering of non-equilibrium surface plasmon polaritons on the grating makes a significant contribution to the radiation intensity.