The theory, design techniques, and fabrication of high harmonic diffractive (HHD) lenses is presented. HHD lenses are of high interest for ultralightweight and large aperture imaging systems. The interesting chromatic focal characteristics, image quality, and correction subsystems are discussed that can provide high image quality (achromatic and apochromatic) over broad optical bandwidths. A fabrication example is given of an HHD lens combined with a molded glass HHD lens combined with a single-order diffractive Fresnel lens, which is called a multiple-order diffractive engineered surface (MODE) lens. This type of lens is being developed for ultralightweight space telescopes, although they will have application in other areas.
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