Abstract
In the developing field of nonlinear plasmonics, it is important to understand the fundamental relationship between properties of the localized surface plasmon resonance (LSPR) of metallic nanostructures and their nonlinear optical responses. A detailed understanding of nonlinear responses from nanostructures with well-characterized LSPRs is an essential prerequisite for the future design of sophisticated plasmonic systems with advanced functions to control light. In this article, we investigate the second-order harmonic (SH) responses from gold nanocrescent (Au NC) antennas which have wavelength and polarization sensitive LSPRs in the visible and near-infrared wavelength ranges. The wavelength dependence of the SH intensity exhibits spectral profiles different from dipole LSPR bands in absorbance spectra. The incident polarization angle dependence was found to vary significantly when the excitation wavelength was tuned over the dipole band. Finite-difference time-domain calculations coupled with a nonlinear hydrodynamic model were carried out for Au NC arrays to investigate the local field enhancement of the incoming fundamental and emitting SH light. The experimental and theoretical results indicate that the effects of higher-order LSPRs, such as quadrupole and multipole resonances, occurring at SH wavelengths are important in governing the SH generation process. Also, it is shown that the incident polarization angle dependence of SH signals is very strongly sensitive to nanoscale variations in the NC's shape.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 20424-20435 |
| Number of pages | 12 |
| Journal | Journal of Physical Chemistry C |
| Volume | 124 |
| Issue number | 37 |
| DOIs | |
| State | Published - Sep 17 2020 |
Funding
This research work was supported by grants from the U.S. National Science Foundation (CHE-1414466 and CHE-0802913) to N.-H.G., J.S.S.-P., and G.C.S. and the Air Force Office of Scientific Research (FA9550-19-1-0009) to M.S. Secondary instrumentation and personnel supports were, respectively, from U.S. NSF CHE-1310693 and CHE-1905395 to N.-H.G. C.A.L. also acknowledges support from an NSF Integrative Graduate Education and Research Traineeship (DGE-0903715). The authors also acknowledge computational support through the Department of Defense High Performance Computing Modernization Program and the use of the Laser Spectroscopy Labs at the University of California, Irvine. The research made use of University of Utah shared facilities of Micron Technology Foundation, Inc. Microscopy Suite sponsored by the College of Engineering, Health Sciences Center, Office of the Vice President for Research, and the Utah Science Technology and Research (USTAR) initiative of the State of Utah and the University of Utah USTAR shared facilities supported, in part, by the NSF MRSEC Program (DMR-1121252).
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- General Energy
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films