Shape-Dependent Terahertz Radiation Generation Through Nanoparticles

Abstract

Through this theoretical study, nanoparticles-based Terahertz (THz) emission is explored out by considering the graphite nanoparticles (NPs) of two different shapes, i.e., spherical (SNPs) and cylindrical (CNPs), oriented in two normal directions, i.e., one having their basal plane perpendicular to the electric field of the laser and second with their basal plane parallel to the electric field of the laser. The nonlinear ponderomotive force is exerted on the electronic cloud of NPs by the field of two incident super-Gaussian lasers of frequencies ω1 and ω2, which on excitation gives rise to the nonlinear macroscopic current density at beating frequency ω = ω1 − ω2. It is observed that efficient THz emission takes place when the beat frequency matches with the effective plasmon frequency of the NPs. Most importantly, THz generation strongly depends on the shape of the NPs as CNPs contribute more efficiently towards THz generation but orientation of NPs with respect to the electric field feebly affects the THz generation.