ManGrin?

Do any of you know whether one could theoretically create a GRIN-based Mangin mirror that didn't have to have a particular figure, if the GRIN could be tailored to the curvature at each point? Or would rays diverge depending on angle of incidence? I'm just having trouble visualizing this. :S

If it would work, then you could just grab any old smooth surface and make an optic out of it- even float glass. Big IF though.

Any thoughts?

Jess Tauber