THz Radiation Generation Through Graphite Nanoparticles Having Two Different Shapes and Orientations of Basal Planes

Graphite nanoparticles (NPs) in two distinct geometries, i.e., cylindrical and spherical, having two different configurations of their basal planes with respect to the electric field of the laser beam are considered for the terahertz radiation generation with the help of the beating process of two coshyperbolic lasers having frequencies
$\omega _{1}$
and
$\omega _{2}$
. Through analytical treatment, we show that a nonlinear ponderomotive force (~0.47 dyne) that leads to nonlinear oscillating current is responsible for the radiation generation, when there is a matching of surface plasmon frequency of NPs (longitudinal surface plasmon resonance or transverse surface plasmon resonance) and beating frequency of the lasers (
$\omega =\omega _{1}- \omega _{2}$
). A substantial difference of the order of 10
³
in the electric field of radiation is seen in the two configurations of NPs, i.e., when their basal planes are parallel or perpendicular to the field of the incident beams. This study also shows that the radiation field can be controlled by changing the geometry of the NPs, and the conversion efficiency is of the order of
${10}^{-4}$
in the case of the combined system of cylindrical and spherical NPs.