Multiple resonance coupling in an individual germanium nanogroove with organic dyes

Coupling between light and matter has many infusive phenomena and potential applications, especially the interactions between all-dielectric nanostructures and two-level system materials. Here, taking advantage of the extraordinary broad features in the magnetic resonance modes excited in an individual germanium nanogroove with a rough surface fabricated by focused ion beam milling, Fano dips at the wavelength of 520, 589 and 680 nm with an asymmetry parameters of 0.06, −0.20 and −0.25 and a quality factor of 25.5, 40.2 and 38.4 are individually observed in the backward scattering spectra through interacting with 0.03 mM TDBC, S2165 and S0315 dye molecules in 2-propanol solution. In addition, owing to the good dispersibility and stability of mixed dye solution, for the first time, we obtained these three Fano dips at different wavelength simultaneously, indicating the multiple resonance coupling between a single germanium nanogroove and three different organic dyes. These findings suggest a viable strategy for easily tailoring the scattering of an all-dielectric nanogroove, creating a functional building block for biosensing technology or quantum information processing. (paper)