Alternative methods for ray propagation in absorptive media

The determination of a set of Hamilton equations for ray tracing in absorbing media is still an open problem. Recently Suchy proposed another alternative, based on the Connor-Felsen criterion of real propagation vectors. It is shown here that the same criterion can be applied in a different form, leading to yet another alternative. The present method, similarly to a previous one, preserves the analytic properties of the complex ray tracing formalism, and adds to it an appropriate constraint.