Nanolayered polymer diffusive spectral filters

Layer-multiplying coextrusion is a manufacturing technology capable of producing composite nanolayered opticalpolymer films having precisely controlled refractive-index distributions. This technology can be applied to the fabrication of spectral filters based on a variation of the Christiansen filter. The basic idea is to produce an optical component consisting of alternating films of two distinct polymer materials in optical contact, with textured interfaces between adjacent films. By designing the two materials to have refractive indices that are matched at a specific wavelength, such a component can produce significant light scattering for wavelengths far from the index-matched wavelength, with negligible scattering for wavelengths sufficiently close to that wavelength. We discuss the theory and characteristics of this new type of advanced spectral filter, present a number of potential applications, and provide design examples.