We present experimental studies of plasmon excitation by keV Ne and Ar single charged ions on Al surfaces. Plasmons are identi®ed through the characteristic energy spectrum of electrons from plasmon decay. At 1 keV incident energy, surface plasmons are excited by Ne‡ but not by Ar‡. For higher energies we observe bulk plasmon excitation resulting, most likely, from excitation by fast electrons,...

We develop the complete theory for collective plasmon modes of an interacting electron system in presence explicit mass (or velocity) anisotropy corresponding noninteracting situation, with effective Fermi velocity being different along axes. Such is common solid state materials (e.g., silicon or germanium), where surface often not spherical. find that dispersion itself develops significant suc...

We apply the conformal transformation technique to study systematically a variety of singular plasmonic structures, including two-dimensional sharp edges, rough surfaces, and nanocrescents. These structures are shown to exhibit two distinct features. First, different from a planar metallic surface, the surface plasmon excitations on the examined structures have a lower bound cutoff at a finite ...

We present a unified approach which is accurate at all temperatures and densities for calculating the energy loss from a stellar plasma due to the plasma process, the decay of photons and plasmons into neutrino pairs. To allow efficient numerical calculations, an analytic approximation to the dispersion equations for photons and plasmons is developed. It is correct to order α in the classical, ...

We exploit a plasmon mediated two-step momentum down-conversion scheme to convert low-energy tunneling electrons into propagating photons. Surface plasmon polaritons (SPPs) propagating along an extended gold nanowire are excited on one end by low-energy electron tunneling and are then converted to free-propagating photons at the other end. The separation of excitation and outcoupling proves tha...

We present a fully three-dimensional theoretical study of the extraordinary transmission of light through subwavelength hole arrays in optically thick metal films. Good agreement is obtained with experimental data. An analytical minimal model is also developed, which conclusively shows that the enhancement of transmission is due to tunneling through surface plasmons formed on each metal-dielect...

We show that plasmons in two-dimensional graphene can have net gain at terahertz frequencies. The coupling of the plasmons to interband electron-hole transitions in population inverted graphene layers can lead to plasmon amplification through the process of stimulated emission. We show that the net gain values can exceed 10 cm−1 in the 1-10 terahertz frequency range, for electron-hole densities...