  It is now well established that, due to excitation of localized surface
plasmon resonances in plasmonic nanosystems, the electric field from an
external irradiation source is greatly amplified in their vicinity. Surface
plasmon mediated electric field amplification near plasmonic nanosystems is of
vital importance for; light absorption enhancement of solar cells, molecular
detection using surface enhanced Raman spectroscopy, proximity measurement of
biological macromolecules such as proteins, lipids and nucleic acids using
plasmon enhanced FRET, cancer therapy using photothermal effects, just to name
only a few applications. Present work formulates Bergman-Milton multipole
spectral expansion approach for investigating surface plasmon mediated electric
field amplification in the dimer arrangement of Al, Ag and Au nanoparticles. In
comparison to an isolated spherical shaped nanoparticle, their aggregate
provide greater field enhancement, wider spectral tuning, and multiple resonant
features. In view of the superior plasmonic characteristics of dimer
configuration, a systematic investigation of electric field enhancement is done
and their suitability for UV-Visible applications is assessed. The role of
particle size, embedding medium and interparticle separation in field
amplification and wavelength tuning is quantified. Moreover, plasmonic
nanoparticle dimer designs for UV-Visible spectral window are presented.
