Customizing the Topological Charges of Vortex Modes by Exploiting Symmetry Principles

Abstract Vortex modes carrying Orbital Angular Momentum (OAM) provide an ideal platform for realizing many novel physical effects and applications ranging from classical to quantum regimes. An important approach to generating the vortex modes is the electromagnetic (EM) scattering by scatterers holding high degrees of symmetries. Within this context, a clear link is established between the symmetries and the topological charges of the vortex modes. A symmetry matching condition is formulated and a design rule consisting of two simple formulas is suggested to excite a specific topological charge order. The formulas are numerically and experimentally verified by designing a microwave resonator and its feeding network to generate vortex modes with topological charges from to . The reported approach can be applied to microwave, terahertz, and optical applications, and hence provides a holistic design principle for engineering vortex modes for a wide EM spectrum.