Engineering

Computer science

Geometrical optics

Transverse plane

Physics

Optics

Refraction

Spurious relationship

Structural engineering

Data compression

Diffraction

Lossless compression

Machine learning

Computer vision

IEEE Transactions on Antennas and Propagation

Refraction represents one of the most fundamental operations that may be performed by a metasurface. However, simple phase-gradient metasurface designs suffer from restricted angular deflection due to spurious diffraction orders. It has been recently shown, using a circuit-based approach, that refraction without spurious diffraction, or diffraction-free, can fortunately be achieved by a transverse (or in-plane polarizable) metasurface exhibiting either loss-gain, nonreciprocity, or bianisotropy. Here, we re-derive these conditions using a medium-based-and hence, more insightful-approach based on generalized sheet transition conditions and surface susceptibility tensors, and experimentally demonstrate for the first time, beyond any doubt, two diffraction-free refractive metasurfaces that are essentially lossless, passive, bianisotropic, and reciprocal.

Susceptibility Derivation and Experimental Demonstration of Refracting Metasurfaces Without Spurious Diffraction