Abstract: In accordance with the invention, a tunable subwavelength resonant grating filter comprises a liquid crystal cell having a pair of major surface walls. One wall of the cell is a coated subwavelength grating of a SRGF. The coating comprises a polymer layer to fill the grating trenches and a surfactant layer to facilitate uniform alignment of the liquid crystal material. The refractive index of the LCD material in the cell can then be electrically or thermally adjusted to tune the resonant wavelength.

Abstract: In accordance with the invention, a SRG filter is fabricated by disposing a moldable layer on the unpatterned grating layer, pressing a patterned molding surface into the moldable layer to produce an appropriate pattern of reduced thickness regions, removing material from the reduced thickness regions to expose the grating layer and processing the exposed grating layer to form a grating array. In a preferred embodiment the grating layer is adjacent a planar waveguiding layer overlying a substrate and the moldable material is a polymer resist. The waveguide layer advantageously has a refractive index greater than both the grating layer and the underlying substrate. And the pattern can be a one or two-dimensional array of grating elements.