Optimization of plasmonic color filters for CMOS image sensors by genetic algorithm

Utilization of a plasmonic nanohole array as a color filter, proposes important advantages like the compatibility with CMOS processes. A color filter is an important component for applications, such as LCDs, LEDs, CMOS image sensors, etc. In this article, a set of primary color filters (red, green and blue) are designed by an optimization procedure, employing genetic algorithm integrated with Lumerical FDTD software. The filters consist of a square lattice of nanoholes in an aluminum film on a silicon dioxide substrate. They are suitable for using in CMOS image sensors. Despite the practical restrictions to simplify the fabrication, the optical response of the filters have shown a transmission peak of 30-43 percent with a FWHM of 40 (nm), 50 (nm) and 80 (nm) in accurate resonant wavelengths of red, green, and blue filters, respectively. These results demonstrate the efficacy of the proposed optimization method.