  We demonstrate engineering of the spectral content and polarization of
photoluminescence (PL) from arrayed gold nanoparticles atop a
subwavelength-thin dielectric spacer and optically-thick gold film, a
configuration that supports gap-surface plasmon resonances (GSPRs). Choice of
shapes and dimensions of gold nanoparticles influences the GSPR wavelength and
polarization characteristics, thereby allowing us to enhance and spectrally
mold the plasmon-assisted PL while simultaneously controlling its polarization.
In order to understand the underlying physics behind the plasmon-enhanced PL,
we develop a simple model that faithfully reproduces all features observed in
our experiments showing also good quantitative agreement for the PL enhancement
