Electromagnetically induced transparency‐like effect by dark‐dark mode coupling

Abstract

Electromagnetically induced transparency‐like (EIT‐like) effect is a promising research area for applications of slow light, sensing and metamaterials. The EIT‐like effect is generally formed by the destructive interference of bright‐dark mode coupling and bright‐bright mode coupling. There are seldom reports about EIT‐like effect realized by the coupling of two dark modes. In this paper, we numerically and theoretically demonstrated that the EIT‐like effect is achieved through dark‐dark mode coupling of two waveguide resonances in a compound nanosystem with metal grating and multilayer structure. If we introduce |1〉,|2〉 and |3〉 to represent the surface plasmon polaritons (SPPs) resonance, waveguide resonance in layer 2, and waveguide resonance in layer 4, the destructive interference occurs between two pathways of |0〉 → |1〉→ |2〉 and |0〉 → |1〉→ |2〉→ |3〉→ |2〉, where |0〉 is the ground state without excitation. Our work will stimulate more studies on EIT‐like effect with dark‐dark mode coupling in other systems.