Phase-Matched Second-Harmonic Generation from Metasurfaces Inside Multipass Cells

TL;DR

This paper presents a scalable method to enhance second-harmonic generation in metasurfaces by integrating them into multipass cells, achieving phase matching and significant signal amplification through multiple interactions.

Contribution

The study demonstrates phase matching of SHG in metasurfaces within multipass cells, providing a practical approach to boost nonlinear optical responses.

Findings

Achieved an order of magnitude enhancement in SHG signal with up to 9 passes.

Verified phase matching through superlinear dependence of SHG on passes.

Results align well with a simple theoretical model.

Abstract

We demonstrate a simple and scalable approach to increase conversion efficiencies of nonlinear metasurfaces by incorporating them into multipass cells and by letting the pump beam to interact with the metasurfaces multiple times. We experimentally show that by metasurface design, the associated phase-matching criteria can be fulfilled. As a proof of principle, we achieve phase matching of second-harmonic generation (SHG) using a metasurface consisting of aluminium nanoparticles deposited on a glass substrate. The phase-matching condition is verified to be achieved by measuring superlinear dependence of the detected SHG as a function of number of passes. We measure an order of magnitude enhancement in the SHG signal when the incident pump traverses the metasurface up to 9 passes. Results are found to agree well with a simple model developed to estimate the generated SHG signals. We also discuss strategies to further scale-up the nonlinear signal generation. Our approach provides a clear pathway to enhance nonlinear optical responses of metasurface-based devices. The generic nature of our approach holds promise for diverse applications in nonlinear optics and photonics.