1. A multi-spectral imaging (MSI) device, comprising: an imaging plane with at least two groups of pixels in an array of pixels for sensing at least two spectral bands, wherein the at least two spectral bands include a first spectral band and a second spectral band; and a diffractive optic for diffracting an electromagnetic wave into the at least two spectral bands and focusing each spectral band component of the electromagnetic wave onto the group of pixels for the spectral band to generate image.