GRADED ORDER-SORTING FILTER FOR HYPERSPECTRAL IMAGERS AND METHODS OF MAKING THE SAME

摘要

A graded order-sorting filter for hyperspectral imagers and methods of making the same are provided. The graded order-sorting filter includes a substrate wafer having a first side and a second side and is formed of a material that is substantially transparent to light photons. The graded order-sorting filter also includes an absorption filter deposited outwardly from the first side of the substrate wafer. The absorption filter is tapered along a taper direction and formed of a graded composition semiconductor material with a bandgap graded to decrease outwardly from the substrate wafer and/or graded along the taper direction. The graded composition semiconductor material is substantially transparent to the light photons for photon energies substantially less than the bandgap. The above filter can also be aligned to a two-dimensional array of pixels to form a hyperspectral imager.