Wide-spatial scattering and arbitrary-angular tunability based on hybridized phase gradients from metasurface hologram algorithm

Abstract

Light steering and wavefront shaping by metasurfaces typically relies on the elaborate phase arrangement from discrete plasmonic or dielectric resonators. A linear phase gradient profile could simply enable the beam bending (anomalous reflection/transmission) functionality. Comparing to the single beam steering performance, the applicable wide-scattering property is also highly in demand for more practical applications of full-spatial imaging and detection, etc. However, it is still challenging to come up with an efficient design route to manipulate the arbitrary wide-spatial scattering and complex phase gradient hybridization. Here, we propose a metasurface design route that could arbitrarily expand the visible-frequency light scattering into wide outgoing directions. An inverse-design metasurface based on hologram algorithm is created to form the complex phase gradient hybridization and realize wide-spatial scattering covering the outgoing angle range between ±60°. Such design method can also tailor to the arbitrary angular scattering functionality to outgoing angular direction at 15°–30°, 30°–45°and 45°–75°, respectively. Additionally, the proposed architecture operates at broadband visible wavelength rather than a single wavelength, and it also enjoys the robust optical scattering performance which is irrelevant to the incident angle variation. Overall, the presented design route is universal and can easily find applications for optical diffuser, light coupling/de-coupling, directional optical emitter, full-spatial imaging, light trapping and spectrum splitting, etc.