Numerical Study Of Plasmonic Filter Based On Metal-insulator-metal Waveguide

Surface plasmons polaritons is the coupled mode of an external high-frequency electromagnetic wave and free charges on a metal surface and propagate along the the interface as a dilatational wave. SPPs is considered to be a possible solution for the realization of the micro communication element and highly integrated optical circuits. This is mainly due to the unique properties of SPPs, such as breaking through the traditional diffraction limit and local field enhancement. The metal- dielectric- metal(MIM) waveguide has attracted the attention of researchers because of its simple structure, strong bondage of SPPs and further transmission distance.This paper studies the characteristics of the transmission characteristics of the nanometeric plasmonic filter comprising one stub resonators side-coupled with a metal-isolator-metal waveguide and demonstrated numerically by the finite element method. The results show that the longer the length and the narrower the width of the stub,the longer the wavelength of the transmittance dips. Then in the opposite side of the single structure to add a stub, constitute a double-stub structure, through the study find that the distance between the two stubs does not change the position of the transmission dips, only change the transmittivity. Based on the magnetic field distributions on the two dimensional model, the physical origin of transmittance peaks and dips have been clarified by phase analysis of F-P resonance.A novel nanometeric plasmonic filter comprising double-sided eight stub resonators side-coupled with a metal-isolator-metal waveguide is proposed. The numerical results show that the four transmittance peaks in the transmission spectrum range from 400 nm to 2000 nm can be achieved due to the electromagnetically induced transparency(EIT)-like spectral responses between every two adjacent stub resonators with detuned cavity length. In addition, the central wavelengths of transmittance peaks can be tuned by adjusting the cavity length of every stub resonator, which means the waveguide filter could be utilized to develop ultracompact and tunable narrowband photonic filters for high integration.