Electromagnetic wave rotators with homogeneous, nonmagnetic, and isotropic materials.

We propose a novel optical transformation to design an arbitrary N-sided regular polygonal rotator, which demonstrates that the inhomogeneity of a rotator can be completely removed, and only anisotropy is needed to rotate wavefronts without any perturbance. An N-sided regular polygonal rotator will give rise to a rotation angle of 360°/N, thereby leading to a series of discrete rotation angles with different choices of N. Practical realization of such homogeneous rotators is suggested by using only four kinds of nonmagnetic isotropic dielectrics throughout. The dielectrics can be easily arranged in a planarly stratified configuration due to all the flat boundaries, which makes the rotator much easier in fabrication and application. Full-wave simulation validates the proposed scheme applicable to both passive object and active source with excellent performance.