Hyperspectral sensor with diffractive focusing elements and color filters

An imaging device, comprising:

• an image sensor, including:
• a sensor substrate;
• an element substrate, wherein the element substrate is disposed on a light incident surface side of the sensor substrate;
• and
• a plurality of pixels disposed in the sensor substrate, wherein each pixel in the plurality of pixels includes:
• a plurality of sub-pixels;
• a plurality of diffraction elements, wherein the diffraction elements are disposed in a first layer of the element substrate, wherein at least one of the diffraction elements partially overlaps more than one sub-pixel, and wherein the diffraction elements are asymmetrically disposed about an area of the pixel;
• and
• a plurality of color filters, wherein the color filters are disposed in a second layer of the element substrate.

A method, comprising:

• receiving incident light at an image sensor having a plurality of pixels;
• for each pixel in the plurality of pixels, diffracting using a set of diffraction elements and partially filtering using a plurality of wavelength filters the incident light onto a plurality of sub-pixels;
• for each pixel in the plurality of pixels, determining a ratio of a signal strength generated by the sub-pixels in each unique pair of the sub-pixels in response to the incident light;
• and
• determining a color of the incident light at each pixel in the plurality of pixels from the determined ratio of signal strength at each of the sub-pixels.