  Digital color imaging relies on spectral filters on top of a pixelated
sensor, such as a CMOS image sensor. An important parameter of imaging devices
is their resolution, which depends on the size of the pixels. For many
applications, a high resolution is desirable, consequently requiring small
spectral filters. Dielectric nanostructures, due to their resonant behavior and
its tunability, offer the possibility to be assembled into flexible and
miniature spectral filters, which could potentially replace conventional
pigmented and dye-based color filters. In this paper, we demonstrate the
generation of transmissive structural colors based on uniform-height amorphous
silicon nanostructures. We optimize the structures for the primary RGB colors
and report the construction of sub-micrometer RGB filter arrays for a pixel
size down to 0.5 {\mu}m.
