Enhanced Surface Second Harmonic Generation in Nanolaminates
Abstract
Second-harmonic generation (SHG) is a second-order nonlinear optical process that is not allowed in media with inversion sym-metry. However, due to the broken symmetry at the surface, surface SHG still occurs, but is generally small. We experimentally investi-gate the surface SHG in periodic stacks of alternating, subwave-length dielectric layers, which have a large number of surfaces, thus enhancing surface SHG considerably. To this end, multilayer stacks of SiO2/TiO2 were grown by Plasma Enhanced Atomic Layer Deposition (PEALD) on fused silica substrates. With this technique individual layers of a thickness of less than 2 nm can be fabricated. We experimentally show that under large angles of incidence (> 20 degrees) there is substantial SHG, well beyond the level, which can be observed from simple interfaces. We perform this experiment for samples with different periods and thickness of SiO2/TiO2 and our results are in agreement with theoretical calculations.
Cite
@article{arxiv.2301.08089,
title = {Enhanced Surface Second Harmonic Generation in Nanolaminates},
author = {Fatemeh Abtahi and Pallabi Paul and Sebastian Beer and Athira Kuppadakkath and Anton Pakhomov and Adriana Szeghalmi and Stefan Nolte and Frank Setzpfandt and Falk Eilenberger},
journal= {arXiv preprint arXiv:2301.08089},
year = {2023}
}