Abstract
Gradient Index Lens (abbreviated as GRIN Lens) is based on optic theory of refractive index distribution in optical material to achieve the optical performances of a lens. For the cases of flat GRIN Lens, positive and negative power optical lenses are made by varying the refractive index distribution in the lenses. Compared with conventional lenses rely on the spherical surfaces to refract light rays, GRIN Lenses can reduce the number of lenses used in lens modules and simplify the lens assembly. This thesis is devoted to the theory of distribution in refractive index in GRIN lenses with aberrations analysis and measurement of the GRIN lenses. Initially, with 2.0 mm focal length and 0.5 mm length thickness, the GRIN lens is designed with a clear aperture radius being 0.2 mm. Through the design of radial (vertical the optical axis) and axial (along the optical axis) gradient refractive index distribution of lens, the axial chromatic aberration of GRIN lens in visible light spectrum is optimized; then, with Shack - Hartmann wavefront sensor to detect optical path difference of the GRIN lenses, the aberration of lenses are fully explored. In the manufacture of GRIN lenses, high-power laser beam for curing of polymers at 3-axis mechanical stage is adopted for manufacture of micro optical lens elements. The investigation of the contact performance of photo-curable polymer on silicon substrate is done then the morphology and accuracy of lenses are considered. The goal is to provide a high-efficiency, high-precision, highly flexible lens manufacture method.