Guided-wave optical thin-film Luneburg lenses: fabrication technique and properties

With computer-aided design and a digital-controlled lathe, shadow sputtering masks have been made with precisely tailored contour for the fabrication of guided-wave optical thin-film Luneburg lenses. Nearly diffraction-limited performance has been obtained reproducibly for a family of thin-film circular lenses ranging between F/4 and F/30 derived from generalized thin-film Luneburg lens profiles when only the center portion of the lens aperture is employed, in good agreement with numerical ray-tracing results. Both the design and construction of the mask and the analytical as well as experimental results of the thin-film generalized Luneburg lenses are reported. In addition, the fabrication tolerance for this guided-wave optical lens system is described.