Active control of electromagnetically induced transparency with dual dark mode excitation pathways using MEMS based tri-atomic metamolecules

We report experimental results of the active switching of electromagnetically induced transparency (EIT) analogue by controlling the dark mode excitation pathways in amicroelectromechanical system based tri-atomic metamolecule, operating in the terahertzspectral region. The tri-atomic metamolecule consists of two bright cut wireresonators (CWRs) on either side of the dark split ringresonators (SRRs). Each of the CWRs can independently excite the dark inductive-capacitive resonance mode of the SRRs through inductive coupling, and this allows for the dual pathways of dark mode excitation. The CWRs are made movable along the out-of-plane direction and electrically isolated to achieve selective reconfiguration. Hence, by controlling the physical position of these CWRs, the excitation pathways can be actively reconfigured. This enables the strong excitation of EIT analogue at 0.65 THz, only when one of the pathways is made accessible. Moreover, the transparency peak is completely modulated when both pathways are made either inaccessible or equally accessible. The proposed approach of realizing independent control of constituentresonators in a multi-resonator coupled system, enables the realization of efficient slow light devices and tunable high-Qresonators in terahertzspectral region.

Source: Applied Physics Letters - November 23, 2016 Category: Physics Authors: Prakash Pitchappa, Manukumara Manjappa, Chong Pei Ho, Ranjan Singh, Navab Singh and Chengkuo Lee Source Type: research