Double-Resonant Plasmonic Molecule: Enhanced Vibrational Induced Scattering Modulation

The present publication investigates the optical scattering behavior of an artificial near-field coupled double-resonant plasmonic molecule on a glass substrate formed by a linear arrangement of three gold nanobars. The aim of the proposed symmetrical structure arrangement is to achieve a significant increase in the feedback of optically induced coherent mechanical oscillations on the scattering cross-section. Based on the description of isolated dipole-like plasmonic nanostructures, it is shown how an increase of the modulation strength can be achieved by systematic utilization and modification of the inherent near-field coupling effect. It is shown which differences exist compared to an isolated plasmonic nanostructure, especially for the NIR spectral range. To the best of our knowledge, this is the first investigation showing the behavior of coherent acoustic vibrations in such artificial plasmonic molecules at an optical carrier wavelength of 1560 nm which is particularly interesting for applications in the field of optical communication.