The purpose of an imaging system is to collect and focus light scattered from an object thus forming an image of the object, which is then detected either by the human eye, by a photosensitive film, or by a detector array. Imaging systems often magnify or demagnify an object. One of the figures of merit to qualify an imaging system is the resolution. Resolution is the measure of how sharply an image can be generated. It is a measure of the spatial frequency response of the imaging system. The fundamental limiting parameter of the resolution of a conventional optical imaging system is the optical wavelength. A factor that affects resolution is aberration in the optical systems. Chromatic aberrations are aberrations that are due to the fact that the refractive index of an optical element are wavelength dependent, and therefore the focal point of a single lens is different at different wavelengths.