No abstract

We demonstrate the excitation of dark plasmon modes with linearly polarized light at normal incidence in self-assembled layers of gold nanoparticles. Because of field retardation the incident light field induces plasmonic dipoles that are parallel within each layer but antiparallel between the layers resulting in a vanishing net dipole moment.Using micro-absorbance spectroscopy we measured a pronounced absorbance peak and reflectance dip at 1.5 eV for bi-and trilayers of gold nanoparticles with a diameter of 46 nm and 2 nm interparticle gap size. The excitation was identified as the dark interlayer plasmon by finite-difference time-domain simulations. The dark plasmon modes are predicted to evolve into standing waves when further increasing the layer number which leads to 90% transmittance of the incident light through the nanoparticle film. Our approach is easy to implement and paves the way for large-area coatings with tunable plasmon resonance.

We demonstrate the excitation of dark modes and creation of hot electrons using linearly polarized light and scalable, cost-effective plasmonic surfaces.