Vertical Plasmonic Resonant Nanocavities

We demonstrate plasmonic modes in a vertical nanocavity with an air output window at the top surface and Ag reflectors. The resonances of surface plasmon polaritons are investigated using cathodoluminescence spectroscopy. The resonant modes are determined by comparing experiment and theoretical simulations. The plasmon dispersion relation in the vertical nanocavities shows a strong confinement to the electromagnetic field, and the smallest modal volume is only 0.0014 μm3. Our work provides insights into the development of nanoscale plasmonic vertical cavity surface-emitting lasers.