Realizing Multispectral Fabry–Perot Structural Color Filters Based on Optical Nanostructures on a Complementary Metal Oxide Semiconductor Chip

A complementary metal oxide semiconductor-compatible transmission filter composed of subwavelength nanostructures is demonstrated through design, numerical modeling, and experimental verification. The tuning of the filters’ peak wavelength via lithographic means in a single dielectric layer, obviating the need for altering the device layer thickness to achieve different filter wavelengths is demonstrated. The Fabry–Perot function is achieved by sandwiching the nanostructures between a bottom distributed Bragg reflector and a top reflector composed of a layer of silver. A spectral resolution of 10 nm–30 nm full width at half maximum and peak transmission efficiency of ≈70% in the multispectral optical filters in both numerical simulations and experimental characterization is experimentally demonstrated. This approach provides a new paradigm in which to achieve color filters, eliminating the need for multiple mask steps for varied device layer thicknesses conventionally used to achieve Fabry–Perot filters, greatly reducing the manufacturing process cost and complexity.