1. A spectral imaging system, comprising: a) a first imaging lens; b) a first image sensor; c) a single phase transmitting diffractive optical element positioned in a first imaging path extending between a source object and the first image sensor through the first imaging lens, the single phase transmitting diffractive optical element designed to disperse light originating from the source object to form, in a single shot, a diffused-dispersed image of the source object on at least a part of the first image sensor; and d) a processor configured to process the diffused-dispersed image into a plurality of spectral images of the source object.