A hybrid coupling model for radiating two-resonator structures with both near-field and far-field interactions

Recently increased attention is paid to optical analogue of electromagnetically induced transparency (EIT). Various classical EIT configurations have been proposed in different optical platforms, showing a great potential for such applications as compact slow-light devices and low-loss matematerials. In previous studies, only near-field coupling is considered. In fact, for more general two-resonator models, both near-field coupling and radiative interaction make contributions. We develop a hybrid coupling model that includes complex interactions to provide new insight into the coupling between two radiating resonators. It is shown that the previous classical EIT models are special cases of the hybrid coupling model. By introducing near-field and far-field coupling simultaneously, one can achieve novel electromagnetic responses. Microwave experiments are performed to realize this theoretical model, and various lineshapes are achieved by delicately tailoring the hybrid coupling.