Perfect Anomalous Reflection and Refraction Accompanied by an Ideal Polarization Conversion: Potential of a Chiral Metasurface

Electrically thin layers, composed of subwavelength-size inclusions known as metasurfaces, are exploited to shape the wavefront of electromagnetic waves. In this work, we engineer ideal polarization rotator metasurfaces which perfectly reflects or refracts a normally illuminated electromagnetic plane wave into an anomalous direction. Our approach is based on applying boundary conditions to relate the induced electric and magnetic equivalent dipole polarizations per unit-cell to the jump of both electric and magnetic fields at the metasurface boundary, and to find the required electric and magnetic polarization densities, and finally to allocate a desired topology to achieve the aforementioned goals of anomalous scattering. We use an analytical model and demonstrate that such design realizations are achievable using metasurfaces with scatterers possessing a chiral topology.