Invisible surfaces enabled by the coalescence of anti-reflection and wavefront controllability in ultrathin metasurfaces

Reflection inherently occurs on the interfaces between different media. In order to perfectly manipulate waves on the interfaces, integration of antireflection function in metasurfaces is highly desired. In this work, we demonstrate an approach to realize exceptional metasurfaces that combine the two vital functionalities of antireflection and arbitrary phase manipulation in the deep subwavelength scale. Such ultrathin devices confer reflection-less transmission through impedance-mismatched interfaces with arbitrary wavefront shapes. Theoretically and experimentally, we demonstrate a three-layer antireflection metasurface that achieves an intriguing phenomenon: the simultaneous elimination of the reflection and refraction effects on a dielectric surface. Incident waves transmit straightly through the dielectric surface as if the surface turns invisible. We further demonstrate a wide variety of applications such as invisible curved surfaces, cloaking of dielectric objects, reflection-less negative refraction and flat axicons on dielectric-air interfaces, etc. The coalescence of antireflection and wavefront controllability in the deep subwavelength scale brings new opportunities for advanced interface optics with high efficiency and great flexibility. Though existing metamaterial antireflection coatings have been optimized in terms of thickness and functionality, these coatings do not provide phase control in the deep subwavelength scale. Here, the authors report multi-layered metasurfaces that provide both antireflection and phase control.

Automated summary

The authors demonstrate an approach to realize exceptional metasurfaces that combine antireflection and arbitrary phase manipulation in the deep subwavelength scale, allowing for reflection-less transmission through impedance-mismatched interfaces with arbitrary wavefront shapes.