Absorptive angular-selective filters consisting of dielectric multilayers combined with thin absorbing layers.

We propose a concept of angular-selective filters (ASFs) that transmit the incident light in the transmitting angular ranges and mostly absorb in the blocking ranges. The absorptive ASF consists of a transparent dielectric multilayer combined with a thin absorbing layer, utilizing the change in the fringe pattern of the light intensity in the filter dependent on the incident angle. We clarified the design guide to select the suitable multilayer structure and absorbing material. Concrete structures of three types were designed using Cr for the absorbing material on the basis of ${\text{SiO}_2}/{\text{TiO}_2}$SiO2/TiO2 bandpass, shortpass, and longpass filters, exhibiting the absorptive ASF functions with the transmitting/blocking ranges of 0-10°/10-30°, 0-30°/30-60°, and 10-60°/0-10°, respectively. The present multilayered structures provide a great advantage for practical use: no need for two- or three-dimensional patterning using lithographic techniques.