Impact of the Interband Transitions in Gold and Silver on the Dynamics of Propagating and Localized Surface Plasmons

Abstract

Understanding and modeling of a surface-plasmon phenomenon on lossy metals interfaces based on simplified models of dielectric function lead to problems when confronted with reality. For a realistic description of lossy metals, such as gold and silver, in the optical range of the electromagnetic spectrum and in the adjacent spectral ranges it is necessary to account not only for ohmic losses but also for the radiative losses resulting from the frequency-dependent interband transitions. We give a detailed analysis of Surface Plasmon Polaritons (SPPs) and Localized Surface Plasmons (LPSs) supported by such realistic metal/dielectric interfaces based on the dispersion relations both for flat and spherical gold and silver interfaces in the extended frequency and nanoparticle size ranges. The study reveals the region of anomalous dispersion for a silver flat interface in the near UV spectral range and high-quality factors for larger nanoparticles. We show that the frequency-dependent interband transition accounted in the dielectric function in a way allowing reproducing well the experimentally measured indexes of refraction does exert the pronounced impact not only on the properties of SPP and LSP for gold interfaces but also, with the weaker but not negligible impact, on the corresponding silver interfaces in the optical ranges and the adjacent spectral ranges.

Heterogeneous Nanoplasmonic Amplifiers for Photocatalysis’s Application: A Theoretical Study

“…Particularly, metallic nanoparticles NPs attracted substantial interest due to their Localized Surface Plasmon Resonance (LSPR). LSPR properties are very promising to enhance the photocatalytic activities in semiconductors, metal-organic framework (MOF), 2D materials, metals, and perovskites [9][10][11][12][13][14][15][16][17]. Recently, different studies have been reported on the importance of plasmonic metallic nanostructures on the engineering of their properties, e.g., the charge transfer, solar absorption, surface chemistry, stability, selectivity, etc.…”

“…Pure metallic NPs are the most used nanomaterials as plasmonic amplifiers due to the high rate of reproducibility and durability of, i.e., Au. Unfortunately, some have limited surface chemistry such as Ag that degrades due to unstable chemical composition, high cost and are deficient optical absorbers as catalysts [13,34]. By coupling a catalytic material as a protective self-assembled monolayer to the nanoplasmonic NPs, the efficiency of plasmonic NPs is improved by tuning the plasmon resonance higher/lower wavelength therefore expanding the absorption response frequency of NPs [13,31,34].…”

“…Unfortunately, some have limited surface chemistry such as Ag that degrades due to unstable chemical composition, high cost and are deficient optical absorbers as catalysts [13,34]. By coupling a catalytic material as a protective self-assembled monolayer to the nanoplasmonic NPs, the efficiency of plasmonic NPs is improved by tuning the plasmon resonance higher/lower wavelength therefore expanding the absorption response frequency of NPs [13,31,34]. Besides, the amplification on the adjacent surface of NPs and catalytic material may be increased, leading to a hot-carrier generation [35][36][37].…”

Improved Refractive Index-Sensing Performance of Multimode Fano-Resonance-Based Metal-Insulator-Metal Nanostructures

“…Recently, refractive index plasmonic sensors based on surface plasmon polaritons (SPPs) [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ] have attracted fascinated attention of the experts of biological and chemical detecting since the benefits of nano-size and conquering the diffraction limit [ 8 , 9 , 10 , 11 ]. SPPs are arisen from the free electrons on the surface of metals and are firmly confined to metal-dielectric interfaces [ 12 , 13 ]. One such example is a sensor based on the surface plasmon resonance (SPR) [ 14 , 15 , 16 , 17 ], a nanometer-sized component that depends on the ultra-high sensitivity of SPPs to the environmental media [ 18 , 19 ].…”

Nonlinear Optical Response of Gold Nanobipyramids for a Doubly Q-Switched Ho-Doped Laser at a Wavelength of 2.1 µm

“…Moreover, PQS operation has attracted much attention from researchers because of the inherent compactness, simplicity, and low cost of their cavities [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. In recent years, the emergence of low-dimensional nanomaterials with saturable absorption characteristics has become one of the major driving factors of PQS operation [ 20 , 21 , 22 ]. Noble metal nanomaterials have attracted wide interest as a result of their relevance to localized surface plasmon resonance (LSPR).…”