We investigate theoretically and demonstrate experimentally using reconfigurable structures that light propagation in a system of three coupled waveguides can behave in full analogy to Electromagnetically Induced Transparency and Autler-Townes effect.
It is shown that light transfer between two evanescently coupled optical waveguides can be interrupted when strong interaction with a third waveguide is induced. In the strong-interaction regime the transfer can be reactivated upon proper detuning of the waveguide propagation constants. These phenomena can be easily understood using the analog of Autler-Townes splitting and electromagnetically induced transparency from atomic physics. Experimental demonstration is provided using photoinduced reconfigurable waveguides.
Abstract A mid-infrared side coupled graphene nanotube waveguide system is proposed to investigate the origin discerning from electromagnetically induced transparency (EIT) to Autler–Townes splitting (ATS). The analytic transmission analysis seeks an evolution tendency of transmission spectrum from ATS to EIT, which is numerically verified by the simulation results. The origin of transparency is mainly attributed to ATS effect in the strong coupling regime while EIT is favored in the weak coupling condition. We plot the field distribution to help understand the underlying physics of the interference process. The high group index of 5000 indicates that a slow light effect is successfully observed and Fano resonance is presented by varying the Fermi energy of the dark mode. These ideas may provide potential views in filters, optical buffers, light storage and on chip metamaterials.