Investigation and analysis of a tunable plasmonic filter based on the Kerr nonlinear effect of a gold nanocomposite

In this study, an all-optical plasmonic filter is introduced based on metal–insulator–metal waveguides coupled with a square nanocavity filled with a nonlinear Kerr material. This structure is numerically investigated using the finite element method. The structure is then analyzed under linear and nonlinear regimes. The nonlinear material inside the square nanocavity includes gold nanocomposite, and its effective parameters are measured using the Maxwell-Garnett theory. The simulation results show that the resonance peak of the filter structure can be adjusted by changing the physical properties of the gold nanoparticles. Furthermore, we can tune the resonant wavelength within the transmission spectrum by considering the Kerr effect of the gold nanocomposite, and by adjusting the incident light signal without changing the dimensions and physical characteristics of the proposed filter structure. Due to the compact size and the simplicity of fabrication, the proposed plasmonic nanofilter is an ideal option for designing the integrated optical circuits.