Lattice Resonances Induced by Periodic Vacancies in Arrays of Nanoparticles

Abstract

Periodic arrays of nanoparticles are capable of supporting lattice resonances, collective modes arising from the coherent interaction of the particles in the array. These resonances, whose spectral position is determined by the array periodicity, are spectrally narrow and lead to strong optical responses, making them useful for a wide range of applications, from nanoscale light sources to ultrasensitive biosensors. Here, we report that, by removing particles from an array in a periodic fashion, it is possible to induce lattice resonances at wavelengths commensurate with the periodicity of these vacancies, which would otherwise not be present in the system. Using a coupled dipole approach, we perform a comprehensive analysis of how the properties of these vacancy-induced lattice resonances depend on the array periodicity, the particle size, and the number of vacancies per unit of area. Furthermore, we find that these lattice resonances have a subradiant character and originate from the symmetry breaking introduced in the unit cell by the presence of the vacancies. Finally, we investigate a potential implementation of an array with vacancies made of nanocylinders embedded in a homogeneous dielectric environment. The results of this work serve to advance our understanding of lattice resonances and provide an alternative method for controlling the optical response of periodic arrays of nanostructures.