The vortex beams conversion from the optical range into the radio domain based on the nonlinear generation of the difference frequency

In this paper, we consider the conversion of optical vortex beams into the terahertz radio domain based on the nonlinear difference frequency generation in a medium with second-order susceptibility. A theoretical substantiation of the law for converting topological charges of vortex beams is given, according to which the topological charge of the output vortex beam is equal to the difference between topological charges of the input optical vortex beams. A simulation model of the processes under consideration is implemented.