Poly-periodic hole arrays for angle-invariant plasmonic filters.

We suggest a plasmonic filter with novel hole arrays for an angle-invariant optical response. The suggested patterns consist of randomly distributed polycrystalline domains in which nano sized holes are arranged with the same period. While the microscopic area of periodicity determines the center wavelength and transmission intensity, the broken periodicity of each domain contributes to restrain the angle dependency. The results increase the possible use of nanohole-based filters in practical area.