INDEX-DISTRIBUTED PLANAR MICROLENSES FOR 3-DIMENSIONAL MICROOPTICS FABRICATED BY SILVER-SODIUM ION-EXCHANGE IN BGG35 SUBSTRATES

Fabrication of planar microlens arrays by silver-sodium ion exchange i s possible by using a new glass type, optimized for this technology. B ecause of its nonlinear diffusion response it is well suited to the fa brication of microlens arrays. We show that the diffusion coefficient can be described theoretically by an exponential concentration depende nce. The parameters of the planar microlenses are measured interferome trically and by imaging experiments. Because of the specific index dis tribution, new evaluation techniques for the determination of lens par ameters from interferometric measurements have been applied. We also p resent a simple model that relates the achievable lens parameters to t he diffusion conditions.