Plasmonic cavities for enhanced optical confinement

The ability of nanoparticle to enhance and confine the electromagnetic field is investigated by using an array of silica nanoparticles partially embedded in silver metallic layer. The energy of incident light is effectively confined in strongly coupled nanoparticles due to combination of surface plasmon resonance and cavity resonance. It is observed that the confinement is highly sensitive to the size, shape, location and spacing between the nanoparticles. It is shown that the proposed periodic structure exhibits enhanced optical confinement due to excitation of surface plasmon polaritons (SPPs) within silica nanoparticles. It is found that intensity is enhanced two orders of magnitude as compared to intensity in absence of plasmonic resonance.