title: Optical signatures of the charge of a dielectric particle in a plasma.
abstract: With an eye on dust particles immersed into an ionized gas, we study the effect of a negative charge on the scattering of light by a dielectric particle with a strong transverse optical phonon resonance in the dielectric constant. Surplus electrons alter the scattering behavior of the particle by their phonon-limited conductivity in the surface layer (negative electron affinity) or in the bulk of the particle (positive electron affinity). We identify a charge-dependent increase of the extinction efficiency for low frequencies, a shift of the extinction resonance above the transverse optical phonon frequency, and a rapid variation of the polarization angles over this resonance. These effects could be used for noninvasive optical measurements of the charge of the particle.
authors.affiliation: Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17487 Greifswald, Germany.
authors.forename: R L
authors.initials: RL
authors.lastname: Heinisch
authors.forename: F X
authors.initials: FX
authors.lastname: Bronold
authors.forename: H
authors.initials: H
authors.lastname: Fehske