Diffraction characteristics of a Laguerre–Gaussian beam through a Maksutov–Cassegrain optical system

Maksutov–Cassegrain (MC) systems are widely used in long-range free-space optical (FSO) communication. In this study, analytical expressions for the diffraction field of a Laguerre–Gaussian (LG) beam passing through an MC system have been derived. The numerical results reveal that, in the long-range FSO system, the replacement of a Gaussian beam by the LG beam enhances the emission efficiency of the MC. Furthermore, the MC has a shaping effect on the LG beam, and the orbital angular momentum of the LG beam is not dispersed when the beam is diffracted by the MC.