  We present the vertically illuminated Si compatible mid-infrared
photodetectors based on graphene that forms negative-index metamaterial. The
coupling into a 2D layer at the angles near normal to the surface is negligible
without the help of a metamaterial. We propose a low loss metamaterial, the
dielectric structure with the nano/microholes through 2D materials that
supports a resonance and enhances quantum efficiency in a wide range of
incident angles.
