A structure for narrow-band coupler type plasmonic filter and wavelength de-multiplexer

The authors present a structure for coupler type narrow-band infrared filter and a wavelength de-multiplexer that is tunable by device parameters. Numerical simulation is realized in a two-dimensional (2D) plasmon polariton metal using finite difference time domain (FDTD) method with a perfectly matched layers (PMLs) boundary conditions. The filter can be used as a selective and rejection type plasmonic filter simultaneously; this is a unique feature of this filter structure. The tunable characteristics of the central wavelength of the filter are discussed. By using the filter, design of a 1×3 wavelength de-multiplexer is also outlined.