Plasmon localization and local field distribution in metal-dielectric films

Abstract

An exact and very efficient numerical method for calculating the effective conductivity and local-field distributions in random R-L-C networks is developed. Using this method, the local-field properties of random metal-dielectric films are investigated in a wide spectral range and for a variety of metal concentrations p. It is shown that for metal concentrations close to the percolation threshold (p=p(c)) and frequencies close to the resonance, the local-field intensity is characterized by a non-Gaussian, exponentially broad distribution. For low and high metal concentrations a scaling region is formed that is due to the increasing number of noninteracting dipoles. The local electric fields are studied in terms of characteristic length parameters. The roles of both localized and extended eigenmodes in Kirchhoff's Hamiltonian are investigated.

Fluctuations of the Local Density of States Probe Localized Surface Plasmons on Disordered Metal Films

“…3(a) and the relative variance of the near-field intensity pattern measured by scanning nearfield optical microscopy (SNOM) on similar samples [15]. These SNOM measurements have led to the conclusion that localized modes should dominate around the percolation threshold (but not exactly at percolation), in agreement from expectations resulting from numerical simulations [31]. An advantage of our direct measurement of the LDOS is that the local intensity of both radiative and nonradiative (dark) modes is probed with the same weight, and with a well-defined instrumental response function.…”

Local field enhancements on gold and silver nanostructures for aperture near field spectroscopy

“…The energy distribution on the intensity map for the two crossed polarizations is different. The intensity takes high values and the PDF decreases exponentially for high intensities tending to a lognormal distribution as predicted by theoretical calculations [16]. These results agree with theoretical prediction [14].…”

“…This strong localization of electromagnetic eigenmodes leads to local field enhancements which have been demonstrated to be proportional to the ratio j 0 m j= 00 m [14]. Therefore, the localized fields can exceed the incident applied field by four to five orders of magnitude [15,16] and silver is expected to exhibit higher enhancements than gold. In this paper, the field enhancements are investigated with a scanning near-field optical microscope (SNOM) and comparison between gold and silver films is done [17,18].…”

Resonant Field Enhancements from Metal Nanoparticle Arrays

“…23 This method provides solutions for site potentials corresponding to E loc (r)/E 0 in L 4 operations, an enormous savings in computing time compared with the L 6 operations required by Gaussian elimination methods. 24 G h is obtained simply as the mean value of G loc ) |E loc (r)/E 0 | 4 within a unit cell of the periodic lattice.…”