Multi-channel Electromagnetic Filters Based on EIT and Fano Resonances through Parallel Segments and Asymmetric Resonators

Abstract

In this study, we investigate electromagnetically induced transparency (EIT) and Fano resonances, focusing on the propagation of electromagnetic waves in a system of parallel waveguides associated with asymmetric resonators. Our design includes five waveguides and two resonators, generating discrete modes influenced by their respective lengths. The EIT resonance is characterized by a prominent transmission peak flanked by two transmission zeros, while the Fano resonance is characterized by a pronounced transmission peak adjacent to a transmission zero. Using the transfer matrix method (TMM), we calculate transmission and reflection rates. Our results indicate that the EIT resonance appears when the resonator lengths show slight differences, whereas the Fano resonance appears when the resonator lengths are identical. Both resonances are sensitive to resonator lengths and permittivity indices. Consequently, the geometrical parameters of the system must be carefully selected according to the application in question, whether waveguiding or multi-channel electromagnetic filtering.