Inhomogeneous optical waveguide lens analysis*

Gradient-index ray-tracing techniques are used to evaluate performance of inhomogeneous optical waveguide lenses. Using the thin-film waveguide parameters including the lens thickness profile, the phase error and diffraction pattern are derived. The procedure is applied to a classical Luneburg index profile for which exact results are known. The results indicate that better than diffraction-limited accuracy can be achieved with reasonable computer running times. A second example demonstrates the procedure on lens profiles approximating generalized Luneburg lenses (image surface is outside the lens).