Abstract
Single crystal germanium is used in infrared spectroscopes and other optical equipment as an excellent infrared optical material. The development of germanium Fresnel lenses not only improves the optical imaging quality but also enables the miniaturization of optical systems. In a previous work, a Fresnel lens with precise curvatures, sharp edges and precise cross-sectional profiles were fabricated by Yan et al. However, sometimes, microcracks will occur to the edge of grooves when the wear of the diamond tool is large in the machining process. In the present work, in order to avoid such microcrack, a novel machining model and machining conditions are proposed for fabricating a high-precision Fresnel lens.