Subwavelength Bayer RGB color routers with perfect optical efficiency

Abstract

We introduce subwavelength color routers with perfect optical efficiency in a red-green-green-blue (RGGB) Bayer layout for solid state image sensors. This is the first demonstration of a subwavelength device concept that shows the full potential of color routing, i.e., perfect routing without loss of photons, with a broadband, polarization-independent, and angular robust response. As an example, we show a color router for 320 nm wide image sensor pixels, which are two times smaller than the smallest state-of-the-art pixels, that features perfect optical efficiency, i.e., no crosstalk between color channels, no reflections, and no leakage into non-photodetector regions, even though the pixel photodetectors are 2-3 times smaller than the wavelength of the incident light. Our color router outperforms all other color separation approaches and can replace the entire optical stack in solid state image sensors.