Polarization and spectral filter arrays based on sub-wavelength structures in CMOS

Polarization and spectral selective sensors can be implemented by using sub-wavelength gratings and hole arrays in metal films, respectively. In this paper we demonstrate the fabrication of so-called wire grid polarizers and hole arrays for color sensing using complementary metal-oxide semiconductor (CMOS) processes. The simulation of the structures was based on the finite-difference time-domain (FDTD) method, and the layout of the nanostructures using the work flow of integrated circuits. A polarization image sensor was designed and demonstrated, and multispectral sensors were implemented using nanostructures with different spectral filter performances on a single chip.