Beam shaping by nonlinear moir\'e metasurfaces

TL;DR

This study investigates how twisted nonlinear moiré metasurfaces can be used to control and shape nonlinear optical signals, specifically second-harmonic generation, through angle-dependent far-field pattern tuning.

Contribution

It introduces the concept of nonlinear moiré photonics with experimental demonstration of angle-tunable SHG patterns in twisted metasurfaces, advancing nonlinear wavefront shaping techniques.

Findings

Far-field SHG patterns are highly tunable by twisting angles.

Interlayer interactions significantly affect nonlinear optical responses.

Moiré phenomena enable new control over nonlinear wavefronts.

Abstract

This paper explores the interplay of momentum transfer and nonlinear optical processes through moir\'e phenomena. Momentum transfer plays a crucial role in the interaction between photons and matter. Here, we study stacked metasurfaces with tailored dispersion and rotated against each other with varying twisted angles. The stacking introduces interlayer interactions, which can be controlled by the relative angle between metasurfaces, significantly enriching the resulting response compared to the single layer counterpart. By focusing on second-harmonic generation (SHG) from these twisted metasurfaces, we delve into the realm of nonlinear moir\'e photonics. Through experimental observations, we unveil the emergence of intricate far-field SHG radiation patterns, showing their effective tuning by varying the twisted angles. These findings offer a fresh perspective to explore nonlinear wavefront shaping through moir\'e phenomena, opening new avenues for nonlinear information processing, optical steering, and nonlinear optical switching.