Distributed-index planar microlens.

Planar technology has been used to make a microlens array monolithically. By selectively diffusing a dopant into the planar substrate a distributed-index planar microlens has been realized. The monomer exchange technique for the plastic substrate and ion exchange and electromigration techniques for the glass substrate are used. In particular a 2-D planar microlens array was fabricated in a glass substrate. Each microlens was 1.2 mm in diameter and the focal length was 9.4 mm. The focused spot of the collimated He-Ne laser beam was as small as 17 micromphi.