A transmission filter apparatus is provided that includes: (i) a substrate to serve as a foundation for the apparatus; (ii) a layer containing resonant dielectric cavities separated by conductive regions. The dimensions and design of the dielectric cavities, thickness of the layer, and substrate, dielectric and conductive materials are chosen to achieve resonant transmission of selected wavelengths. In a particular one or more embodiments, the layer is one dimensional, i.e. you have dielectric cavities along one axis in the plane that are comparatively infinity long in the parallel plane. In a particular one or more embodiments, the layer is two dimensional, i.e. you have dielectric cavities along both axis in the plane. The dimensions in each plane may or may not be equal. In a specific one or more embodiments, the dielectric cavities are terminated on the top and/or bottom by thin metal films with small apertures or tapers.