Electrically tunable Fano resonance based on ring resonator coupled with a stub

Abstract

The electrical control of Fano resonance via a plasmonic waveguide system which is composed of a metal-air-metal stub coupled with ring cavity is presented. An organic material with a large electro-optical coefficient is incorporated in the stub to tune the Fano resonance by the external voltage. Two dimensional finite difference time domain method is used to calculate the transmission and field distribution. The Fano resonance is originated from the coupling between the stub and the ring resonator. The asymmetrical Fano linestyle can be tuned by changing the applied voltage or the geometrical parameters. The proposed plasmonic structure may have application in slow light device, nanoscale filter, all optical switch and refractive index sensor.