Tunable Fano Resonances and Electromagnetically Induced Transparency in All-Dielectric Holey Block

The optical properties of a simple planar silicon nanoblock with cylindrical hole operating at terahertz (THz) frequencies are investigated. The proposed nanostructure exhibit low loss electromagnetically induced transparency (EIT) and Fano resonances, which arises due to the near-field coupling between the nanoblock and cavity modes. The line shape of these resonances can be considerably modified and tuned by varying the geometrical parameters. Furthermore, the symmetry breaking conception is also introduced, which enables higher-order dark hybridized modes to interact with each other, resulting in a dual EIT and Fano resonances in the optical spectrum. The EIT and Fano resonances present high local field enhancement (33) and Q-factors (584) due to extremely low absorption loss. This makes the proposed design an ideal platform for low loss slow-light devices and multi-wavelength biosensing applications.