Distributed-index formation process in a planar microlens

Abstract

It is made clear theoretically and experimentally how the 3-D index distribution in a planar microlens is formed in the fabrication process. The combination of both drift and thermal diffusion of ions plays an important role in achieving an index profile for low aberration. The lens dimension and migration time are determined mainly by ion drift aided by the electric field. A very strong concentration dependency exists in the diffusion coefficient and this brings about an upward convex index shape up to the periphery resulting in full utilization of the index difference.