Dual coupled-resonator system for plasmon-induced transparency and slow light effect

• High transmission of ~92%, narrow FWHM of ~25 nm and high group index of ~75 are realized to be used as an high-performance EIT-like filter with the proposed system.
• Our system is tunable with the peak transmission wavelength, transmission and group index in a large scale.
• Dual transmission peaks are appeared with asymmetrical radius of nanodisks.
• Method of temporal coupled-mode theory and accurate FDTD simulation are used to investigate the proposed structure in detail.

We proposed a dual coupled-resonator system based on the metal-insulator-metal bus waveguide and numerically investigated the plasmon-induced transparency and slow light effect with the Finite-Difference Time-Domain simulations in this paper. The electromagnetically induced transparency-like spectral response will occur between two adjacent stub resonators with detuned resonant wavelength due to the phase-coupled effect. The transmissivity and group index equations were been deduced, which indicated that the system can achieve the effect of the multiple electromagnetically induced transparency-like and slow light. With the optimization, the single peak transmission can reach to as high as 92%, dual PIT transmission peaks appear, as well as group index can reach over 75. These characteristics indicate multiple applications of our system in integrated optical circuits.