Ultra-High-Efficiency Anomalous Refraction with Dielectric Metasurfaces

Anomalous refraction is a form of extreme waveform manipulation that can be realized with artificially structured nanomaterials, such as metamaterials or metasurfaces. While this phenomenon has been previously demonstrated for select input and output angles, its generalization to arbitrary angles with high efficiencies remains a challenge. In this study, we show that periodic dielectric metasurfaces can support ultra-high-efficiency anomalous refraction for nearly arbitrary combinations of incident and outgoing angles (>90% efficiency for angles up to 50°). Both polarization-dependent and polarization-independent device configurations can be realized, and the achieved metrics exceed the capabilities of conventional metasurfaces by a large margin. Many of the devices studied here utilize dielectric nanostructures that support strong near-field optical interactions with neighboring structures and complex optical mode dynamics. We envision that these concepts can be integrated with practical applications in optical communications, spectroscopy, and laser optics.