Spectral sorting of visible light using dielectric gratings

We present the concept of spectral sorting using normalized optical efficiency and systematically study the dielectric based multilayer structure for spectral sorting of visible light with silicon as the absorbing material. We show that by using grating structures, the spectral sorter structures are more efficient when the detector size is less than 1µm, enabling the shrinking of the detector size to the wavelength scale. A comprehensive design strategy is derived that could be used as a design guideline to achieve the sorting of visible light. We show that for pixel size as small as 0.5µm, optical efficiency as high as 80% could be achieved using dielectric based sorting structures.