US Patent 6917472 Achromatic fresnel optics for ultraviolet and x-ray radiation

An achromatic Fresnel optic that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The AFO has a wide range of potential applications in lithography, microimaging with various contrast mechanisms and measurement techniques.