Mode transformation properties in the integrated bimodal resonance structure

The bimodal resonance phenomena in photonic structure have received particular attention due to their intriguing optical properties and numerous potential applications. In this work, we investigated the mode transformation behaviors of the guided modes in an integrated bimodal resonance structure consisting of a single groove on the surface of an abruptly ended slab waveguide. Numerical simulations demonstrated that the strong mode transformation can occur in the anticrossing region of resonance at the oblique incidence of a transverse electric (TE)-polarized guided mode on the groove. According to the multiple-beam interference model, a theoretical formula was developed to study the resonance and mode transformation behaviors of the guided modes. The results showed that the different anticrossing behaviors of structure are resulting from the constructive and destructive interference of bimodal resonance. The resonance and mode transformation properties of structure can be controlled by adjusting the geometrical parameters of groove. The mode manipulation with high efficiency in the slab waveguide will have many applications in lab-on-a-chip devices, switching and on-chip spectroscopy.