Using a 2D eigenvalue solution as a scattering boundary input in a 3D simulation

Dear all,

I have a simulation that solves for a whispering gallery mode in a toroidal geometry. This is done using a 2D PDE solver. This file is attached and is adapted from Mark Oxborrow's work: sites.google.com/site/markoxborrow/axsym.

I want to take this 2D solution, and let it propagate from a boundary into a fully 3D electromagnetic wave simulation. Is there anyway to accomplish this?

Thanks,

Matt