Propagation of arbitrarily polarized terahertz Bessel vortex beam in inhomogeneous unmagnetized plasma slab

Abstract

On the basis of vector plane wave spectrum expansion, the reflection and transmission characteristics of an arbitrarily polarized terahertz Bessel vortex beam by an inhomogeneous unmagnetized plasma slab are investigated. Magnitude profiles of electric field components in the transverse plane, which is perpendicular to the central axes of the reflected and transmitted beams, as well as the weight distributions of orbital angular momentum (OAM) states, are displayed for both homogeneous and inhomogeneous unmagnetized plasma slabs. The results indicate that the magnitude profiles of electric field components for both the reflected and transmitted beams have a serious distortion which is more distinct for the inhomogeneous plasma slab, resulting in diverse patterns which are different from those of the incident beam. Compared with the incident beam, many adjacent OAM states are derived in both the reflected and transmitted beams. For the incidences of both the x- and circular-polarizations, the weight of the predominant OAM state in the reflected beam for the homogeneous plasma slab is greater than that for the inhomogeneous plasma slab but contrary to this conclusion for the transmitted beam. The deformation of OAM states cannot be reflected by the patterns of the field distribution directly. Polarization has few effects on the weight of OAM states of the transmitted beams to the same plasma slab. The weight of the predominant OAM state in the transmitted beam rises with an increase in the incident angle, which is contrary to the conclusion in the reflected beam.