Size dependence of multipolar plasmon resonance frequencies and damping rates in simple metal spherical nanoparticles

Multipolar plasmon oscillation frequencies and corresponding damping rates for nanospheres formed of the simplest free-electron metals are studied. The possibility of controlling plasmon features by choosing the size and dielectric properties of the sphere surroundings is discussed. Optical properties of the studied metals are described within the Drude-Sommerfeld model of the dielectric function with effective parameters acounting for the contribution of conduction electrons and of interband transitions. No approximation is made in respect of the size of a particle; plasmon size characteristics are described rigorously. The results of our experiment on sodium nanodroplets [1] are compared with the oscillation frequency size dependence of dipole and quadrupole plasmon.Comment: Eur. Phys. J. Special Topics 144, 93-99 (2007

Evolution of Laser Light Induced Sodium Clusters

We investigated the growing sodium clusters, induced by the laser light resonant with a sodium dimer transition. We observed the intensity of light scattered by clusters. The clusters were produced in the stainless steel cell containing sodium vapor and helium. We obtained data on cluster mean size and dynamics from fitting the theoretical formulas to the experimental data. The model of clusters' evolution basing on the thermodynamics of the vapor-liquid transition was applied

Size Evolution of the Light Induced Sodium Clusters

We report the observation of the size evolution of the laser light formed clusters. A cell containing sodium vapor and the buffer gas (He) under high pressure was used in the experiment. Changes of the radius and of the density of transient clusters were observed via the time evolution of the intensity of right-angle scattered light. The rate of the cluster radius growth was found to vary from 0.012 to 0.1 μm/s

Collective Scattering of Light on Gold Nanospheres Dispersed in Diethylene Glycol Microdroplet

Light scattering on a freely suspended, evaporating droplet of suspension of gold nanospheres (125 nm radius) in diethylene glycol is studied, revealing both local and nonlocal properties of the system. When the average distance between the nanospheres at the droplet surface matches the wavelength of light, a (broad) maximum, associated with the collective scattering on them, is observed. The number of nanospheres at the droplet surface can be found then. A fine modulation of the maximum is associated with the whispering gallery modes of the composite droplet. The Fano profile identified in the modulation is interpreted as an interference of collective scattering and whispering gallery modes. The ultra narrow enhancement-and-quench structure recognizable in the modulation is interpreted as associated with the creation and destruction of collective oscillation of plasmons of individual nanospheres. It is proposed that this phenomenon can be perceived as whispering gallery modes-assisted creation and destruction of a global plasmon

Collective Scattering of Light on Gold Nanospheres Dispersed in Diethylene Glycol Microdroplet

Light scattering on a freely suspended, evaporating droplet of suspension of gold nanospheres (125 nm radius) in diethylene glycol is studied, revealing both local and nonlocal properties of the system. When the average distance between the nanospheres at the droplet surface matches the wavelength of light, a (broad) maximum, associated with the collective scattering on them, is observed. The number of nanospheres at the droplet surface can be found then. A fine modulation of the maximum is associated with the whispering gallery modes of the composite droplet. The Fano profile identified in the modulation is interpreted as an interference of collective scattering and whispering gallery modes. The ultra narrow enhancement-and-quench structure recognizable in the modulation is interpreted as associated with the creation and destruction of collective oscillation of plasmons of individual nanospheres. It is proposed that this phenomenon can be perceived as whispering gallery modes-assisted creation and destruction of a global plasmon

Evaporation of Micro-Droplets: the "Radius-Square-Law" Revisited

The range of applicability of a fundamental tool for studying the evolution of droplets, the "radius-square-law", was investigated both analytically and numerically, on the basis of the experimental results of our own as well as of other authors. Standard issues were briefly discussed. Departures from the "radius-square-law" caused by the influence of impurities encountered in non-ideal liquids, by the kinetic and surface tension effects encountered for small droplets or by thermal imbalance encountered in light-absorbing droplets were analysed. The entanglement between the kinetic and impurities effects was studied numerically yielding a possible explanation to evaporation coefficient discrepancies found in the literature. An unexpected "radius-square-law" persistence in case of non-isothermal evolutions of very small droplets in atmosphere nearly saturated with vapour was analysed. The coexistence of the kinetic effects and the strong effects of surface tension was found responsible for this effect