Propagation and dynamical characteristics of a Bessel–Gaussian beam in a chiral medium

Abstract

Based on the ABCD transfer matrix and Collins formula, the analytical expressions of the complex amplitude of the Bessel-Gaussian beam in a chiral medium are derived. By introducing vector potential in the Lorentz gauge, the electromagnetic field components of the Bessel-Gaussian beam are determined under the paraxial approximation. Through numerical calculations, the propagation of the Bessel-Gaussian beam in a chiral medium is examined. Results show that Bessel-Gaussian beams split into the left circularly polarized beam and the right circularly polarized beam with different propagation trajectories. The propagation trajectory of the Bessel-Gaussian beam can be controlled by varying half-cone angles of the Bessel-Gaussian beam and the chiral parameter of the medium. The dynamical characteristics, including energy, momentum, spin, and orbital angular momentum, of Bessel-Gaussian beams in a chiral medium are also simulated and discussed in detail. The results will be helpful to understand the interaction mechanism between structured light beams and a chiral medium.