DESIGN OF A DUAL-EFFECT LENS ON LANTHANUM-MODIFIED LEAD-ZIRCONATE-TITANATE FOR CONTINUOUS VARIATION OF FOCAL LENGTH

The design of a Fresnel lens with continuous focal length is proposed for use in optical processing. A convex lens is induced in lanthanum-modified lead zirconate titanate through the application of an electric-field profile supplied by the indium tin oxide electrodes that make up the zones of a Fresnel lens. The use of a numerical method based on fast Fourier transform algorithms was required to analyze accurately the induced field inside a Fresnel lens with an initial focal length of 0.4 m (at 470 nm) and 20 indium tin oxide electrodes. The effective focal location obtained by the combined mechanisms is derived. This design is expected to produce continuous variations of similar to 16% in focal length; the ability of previous designs to achieve focal length switching is maintained.