文摘
We present a systematical study of a subwavelength MIM (metal?insulator?metal) plasmonic waveguide filter with single-cavity and multi-cavity shaped structures by using the finite difference time domain (FDTD) method with perfectly matched layer (PML) absorbing boundary conditions. Both their similar and different characteristics are analyzed, and we find both structures can realize the function of filter, in which several wavelengths are stopped while others can pass through. Both analytical and simulative results reveal that the resonant wavelengths are proportional to the length of the cavity, inversely proportional to the gap between the two slits. Finally, a wideband filter is demonstrated with the multi-cavity structure.