Giant nonlinear response of 2D materials induced by optimal field-enhancement gain mode in hyperbolic meta-structure

TL;DR

This paper introduces a field-enhancement gain (FEG) mode in hyperbolic meta-structures that significantly boosts nonlinear optical responses in 2D materials, surpassing traditional resonant modes in efficiency and bandwidth.

Contribution

The study proposes and demonstrates a novel FEG mode that greatly enhances light-matter interactions in 2D materials, providing a new approach to improve metamaterial-based nonlinear optical devices.

Findings

22145-fold enhancement in second harmonic generation

Conversion efficiency of 1.1×10⁻⁶ W⁻¹ achieved

Broadband high-FEG region over ~80 nm

Abstract

Resonant modes in metamaterials have been widely utilized to amplify the optical response of 2D materials for practical device applications. However, the high loss at the resonant mode severely hinders metamaterial applications. Here, we introduce a field-enhancement gain (FEG) factor to find the FEG mode for significantly improving light-matter interaction. As a demonstration, we experimentally compared the second harmonic generation enhancement of monolayer MoS2 induced by the optimal FEG and resonant modes in hyperbolic meta-structures. With the optimal FEG mode, we obtained an enhancement of 22145-fold and a conversion efficiency of 1.1*10-6 W-1, which are respectively one and two orders of magnitude higher than that previously reported of monolayer MoS2. A broadband high-FEG region over ~80 nm where the nonlinear enhancement is larger than that induced by the resonant mode is achieved. The concept of FEG factor is general to metamaterials, opening a new way for advancing their applications.