I. Introduction
Dusty plasmas are plasmas containing fine charged dust grains. In a low-temperature plasma, and in the absence of a UV radiation flux, dust grains are charged negatively by the collection of plasma electrons and ions. Typically, laboratory dusty plasma experiments use dielectric dust grains such as for example, melamine formaldehyde [1]. Recently, however, there have been suggestions to consider the use of dust particles that have unusual optical properties, such noble metal nanoparticles that exhibit localized surface plasmon (SP) resonances in the visible to near-UV (e.g., [2], [3]). A localized SP resonance corresponds to the excitation of conduction electrons in a “small” metal particle near the electron plasma frequency, where the real part of the dielectric function of the metal is negative. Here, “small” refers to the case when the radius of a spherical grain is much smaller than the inverse wavenumber of the radiation, that is, the grain size parameter , where is the wavelength of the radiation. Strong absorption (or scattering) can occur from noble metal nanoparticles such as gold and silver at these resonances (e.g., [4]–[9]). In metals, the frequency of the SP is in the visible to ultraviolet spectral range, owing to the high density of charge carriers in the metal. SPs can also occur in the lower frequency infrared spectral range in doped semiconductors which have a lower density of free carriers compared to metals [10]. Recently, it has been shown that the frequency of SP resonances in certain semiconductors can be tuned by varying the charge carrier density [11], [12].