Lithium Niobate Metasurfaces

TL;DR

This paper demonstrates subwavelength lithium niobate metasurfaces capable of tunable optical resonances and structural colors, promising ultracompact, multifunctional photonic devices with high efficiency in visible light.

Contribution

Introduction of lithium niobate nanograting metasurfaces with tunable spectral resonances and structural colors for advanced photonic applications.

Findings

Distinct transmission spectral resonances observed

Resonances tunable by structural parameters

High efficiency structural colors achieved

Abstract

Lithium niobate is a multi-functional material, which has been regarded as one of the most promising platform for the multi-purpose optical components and photonic circuits. Targeting at the miniature optical components and systems, lithium niobate microstructures with feature sizes of several to hundreds of micrometers have been demonstrated, such as waveguides, photonic crystals, micro-cavities, and modulators, et al. In this paper, we presented subwavelength nanograting metasurfaces fabricated in a crystalline lithium niobate film, which hold the possibilities towards further shrinking the footprint of the photonic devices with new optical functionalities. Due to the collective lattice interactions between isolated ridge resonances, distinct transmission spectral resonances were observed, which could be tunable by varying the structural parameters. Furthermore, our metasurfaces are capable to show high efficiency transmission structural colors as a result of structural resonances and intrinsic high transparency of lithium niobate in visible spectral range. Our results would pave the way for the new types of ultracompact photonic devices based on lithium niobate.