Design of microelectromechanically tunable metal-insulator-metal plasmonic band-pass/stop filter based on slit waveguides

In this work, the ability of complex metal-insulator-metal (MIM) plasmonic structure to act as an optical band-pass/stop filter in telecommunication window, have been investigated. As a plasmonic device, surface plasmons (SP) and well-confined plasmonic modes are the main guiding tools to transport optical power to long range of MIM structure. In order to study the propagation of these surface waves (SPs) and formation of plasmonic modes in the gap distance between metals, we use both numerical and analytical methods. In which, we have considered finite difference time domain (FDTD) and finite element method (FEM) as numerical methods and microwave Transmission Line Method (TLM) for analytical one. The results of these calculations shows a significant transmission/reflection around λ∼1.55μ mmicrons where these spectral responses are acceptable for realizing band-pass/stop filtering in telecommunication window. Finally, tunability feature have been added by employing Microelectromechanically system (MEMS)-which is called comb-drive. Changing the gap distance between metallic sides in MIM slit, leads to a red or blue shift in the filtering spectra.