Focusing characteristics of Bessel-Gaussian beam passing through Cassegrain antenna system in weak turbulence

The transmission characteristics of the Bessel-Gaussian (BG) beam propagation in free space and turbulence atmosphere after passing through the Cassegrain antenna system are researched in this paper. The research results show that the half-cone angles of the beam and parameters of the optical system can be used to control the propagation trajectory and the cross-talk among different orbital angular momentum (OAM) modes of the BG beam. The BG beam has a focusing property when propagating in free space after passing through the collimating optical system. The trend of cross-talk among different OAM modes is different for focused BG beam and non-focused beam, and the focusing beam can potentially reduce cross-talk among different OAM modes at the receiver plane.