Terahertz radiation generation by laser-resonant excitation of terahertz surface magnetoplasmons on a graphene-n-InSb...

We propose a method for the laser-excitation of terahertz surface magnetoplasmons via the linear mode conversion of terahertz radiation on a graphene sheet deposited on an n-type semiconductor in the presence of an external magnetic field parallel to the semiconductor surface. An obliquely incident p-polarized laser beam interacting with the graphene-n-InSb semiconductor surface imparts linear oscillatory velocity to the free electrons. This oscillatory velocity couples with the modulated electron density to generate a linear current density, which resonantly excites terahertz surface magnetoplasmons. It is shown that the amplitude of a terahertz surface magnetoplasmon wave can be tuned by adjusting the external magnetic field (B_{0}), the graphene's Fermi energy (E_{F}), the semiconductor's temperature (T), and the incident angle (θ) of laser. This mechanism has the potential to enable the development of an actively tunable plasmonic device.