Free-standing broadband low-loss optical metamaterial filter

In this paper, we demonstrate an ultra-thin, low-loss optical metamaterial filter with high transmission and near constant group delay across a broad pass-band from 3.0 to 3.5μ m. Deep-subwavelength air hole inclusions positioned at the corners of a conventional metallodiectric fishnet were used engineer the dispersive properties of the structure to have an impedance match to free space over the pass-band. The optical properties of the metamaterial filter were verified by experimentally fabricating and characterizing the optimized free-standing nano-notched fishnet. The measured experimental results agreed well with the simulated response, showing a high transmission band over the targeted wavelength band.