Retroemission by a glass bead monolayer for high-sensitivity, long-range imaging of upconverting phosphors.

We introduce a retroemitter (REM) device comprising a planar glass bead set placed on a luminescent material substrate, which converges an excitation beam into a set of foci (voxels). The in-voxel emission is collimated by the beads, and propagates upstream over the long range, unlike the out-of-voxel emission spreading in all angles. The REM signal contrast is characterized as a function of incidence and observation angles and propagation distance.

Mie plasmon enhanced diffraction of light from nanoporous metal surfaces.

The diffractive properties of gold films with a periodic lattice of sub-micron voids beneath the surface are investigated. It has been shown that nanoporous metal surfaces exhibit frequency-selective non-dispersive diffraction enhanced by Mie plasmons in nanovoids, which leads to absolute angular tolerance of the diffracted beam intensity that can be useful for a variety of applications covering angle-tolerant optical filters, deflectors, absorbers, and beam splitters. Diffraction spectra are measured and calculated to support these conclusions, showing good qualitative agreement.

Strong coupling of light to flat metals via a buried nanovoid lattice: the interplay of localized and free plasmons.

We study the optical plasmonic properties of metal surfaces which have a periodic lattice of voids buried immediately beneath their flat upper surface. Light reflection spectra calculated in the framework of a self-consistent electromagnetic multiple-scattering layer-KKR approach exhibit two types of plasmon resonances originating from the excitation of different plasmon modes: surface plasmon-polaritons propagating on the planar surface of metal and Mie plasmons localized in the buried voids. Coupling between these two types of plasma oscillation leads to an enhancement of the surface plasmon-polariton resonances even for close-packed void lattices.