Temperature tunable Fano resonance based on ring resonator side coupled with a MIM waveguide

Abstract

The temperature control of Fano resonance via a resonator waveguide system which is composed of a side coupled ring cavity and a metal nanowall is presented. The ring resonator is filled with sealed ethanol which can tune the Fano resonance by the temperature. 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 discrete state and the continua state. The discrete state and continua state is from the side coupled ring resonator and the metal nanowall, respectively. The asymmetrical Fano linestyle can be tuned by changing the temperature of the sealed ethanol or the geometric parameters. Multiple Fano resonance can be obtained by introducing another ring resonator and can be tuned by temperature or size independently. The proposed plasmonic structure may have application in slow light device, nanoscale filter, all optical switch and refractive index sensor.