Localized Surface Plasmon Resonances of Simple Tunable Plasmonic Nanostructures

Abstract

We derive and present systematic relationships between the analytical formulas for calculation of the localized surface plasmon resonances (LSPR) of some plasmonic nanostructures which we have categorized as simple. These relationships, including some new formulas, are summarized in a tree diagram which highlights the core-shell plasmons as the generators of solid and cavity plasmons. In addition, we show that the LSPR of complex structures can be reduced to that of simpler ones, using the LSPR of a nanorice as a case study, in the dipole limit. All the formulas were derived using a combination of the Drude model, the Rayleigh approximation, and the Fröhlich condition. The formulas are handy and they are in good agreement with the results of the plasmon hybridization theory.The formulas also account for dielectric effects, which provide versatility in the tuning of the LSPR of the nanostructures. A simplified model of plasmon hybridization is presented, allowing us to investigate the weak-coupling regimes of solid and cavity plasmons in the core-shell nanostructures we have studied.

Optical properties of a nanoegg–nanorod heterodimer: a quasi-static analysis

“…Likewise, the aspect ratio of a nanorod (NR) enables its LSPR to be tuned with great sensitivity along the longitudinal axis [8][9][10][11][12][13][14][15] . Both the longitudinal dipolar LSPR of a NR 8,[14][15][16][17][18] and the dipolar LSPR of a NE 4,5 have a common property, namely a redshift in their LSPR with an increase in their respective asymmetry parameters, i.e., the aspect ratio of the NR and the core-offset of the NE. When these two nanoparticles are spatially separated by a small gap, a NE-NR heterodimer is formed.…”

“…It has also been shown that plexcitonic systems exhibit EIT 49? ,50 due to the interaction between excitonic resonances of molecular aggregates 50,51 and LSPR of metallic nanostructures 18,49,52 .…”

“…We studied small nanorods to ensure that only dipolar NR plasmons, which can be fully described via a quasi-static approach, are considered. Likewise, radiation broadening of the scattering and absorption spectra 12,18,23,33 , due to radiation of incident light as the particle sizes become comparable to the wavelength of light in the medium, is avoided. The optical properties studied in this work include the effective scattering and absorption spectra of the NE-NR dimer, as well as the characteristics of such hybrid spectra.…”

Stimuli-Activable Metal-Bearing Nanomaterials and Precise On-Demand Antibacterial Strategies

“…The photothermal effect of metal-bearing nanomaterials is caused by the localized surface plasmon resonance (LSPR) generated when they are exposed to specific wavelengths of light. The size, shape, and composition of metal-bearing nanomaterials can affect their excitation wavelengths and thus their LSPR and photothermal activity. − For example, increasing the size of nanomaterials can increase their excitation wavelengths. Irregularly shaped nanomaterials possess multiple excitation wavelengths due to allowing electron clouds to be polarized in different ways.…”

Nurturing Plasmonic Properties of Nanocomposite Thin Films: The Importance of Optimum Oblate Shape

“…Noble metal nanoparticles (MNPs) have appealed researchers a lot with respect to the fundamental as well as emerging applied research because of their fascinating optical properties [1][2][3]. The exciting optical properties appear because of the well-known phenomenon of localized surface plasmon resonance (LSPR) which is the result of coherent oscillation of free electron density at the metal-dielectric interface at the expense of the incident light energy.…”