非共振局域场增强了带有电介质覆盖层的金属纳米岛的二次谐波产生。

Nonresonant Local Fields Enhance Second-Harmonic Generation from Metal Nanoislands with Dielectric Cover.

作者信息

Chervinskii Semyon, Koskinen Kalle, Scherbak Sergey, Kauranen Martti, Lipovskii Andrey

机构信息

Institute of Physics, Nanotechnology and Telecommunication, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, St. Petersburg, 195251 Russia.

Institute of Photonics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland.

出版信息

Phys Rev Lett. 2018 Mar 16;120(11):113902. doi: 10.1103/PhysRevLett.120.113902.

DOI:10.1103/PhysRevLett.120.113902

PMID:29601736

Abstract

We study second-harmonic generation from gold nanoislands covered with amorphous titanium oxide (TiO_{2}) films. As the TiO_{2} thickness increases, the plasmon resonance of the nanoislands shifts away from the second-harmonic wavelength of 532 nm, diminishing the resonant enhancement of the process at this wavelength. Nevertheless, the second-harmonic signal is enhanced by up to a factor of 45 with increasing TiO_{2} thickness. This unexpected effect arises from the scaling of local fields at the fundamental wavelength of 1064 nm-which is at the far tail of the resonance-due to a change in the dielectric environment of the nanoislands.

摘要

我们研究了覆盖有无定形二氧化钛（TiO₂）薄膜的金纳米岛的二次谐波产生。随着TiO₂厚度的增加，纳米岛的等离子体共振偏离532 nm的二次谐波波长，从而降低了该波长下该过程的共振增强。然而，随着TiO₂厚度的增加，二次谐波信号增强了45倍。这种意想不到的效果源于纳米岛介电环境的变化导致的1064 nm基波波长处局部场的缩放，该波长处于共振的远尾部。