All-optical EIT-like phenomenon in plasmonic stub waveguide with ring resonator

An optical phenomenon analogous to electromagnetically induced transparency (EIT) has been proposed and investigated numerically in a plasmonic system, which is composed of a single stub-shaped metal–insulator–metal (MIM) waveguide coupled with a ring resonator. The transmission properties of the system are simulated by the finite-difference time-domain (FDTD) method. The bandwidth of the EIT-like spectrum is mainly dependent on the coupling distance between the stub and ring resonator. The red-shift of EIT-like peak is nearly linearly proportional to the increase in the radius and the refractive index of ring resonator, as is confirmed by the theoretical calculations. Our compact plasmonic structure may find potential applications in highly integrated optical circuits, such as nanoscale filters and optical switching.