  We present a generic transfer matrix approach for the description of the
interaction of atoms possessing multiple ground state and excited state
sublevels with light fields. This model allows us to treat multi-level atoms as
classical scatterers in light fields modified by, in principle, arbitrarily
complex optical components such as mirrors, resonators, dispersive or dichroic
elements, or filters. We verify our formalism for two prototypical sub-Doppler
cooling mechanisms and show that it agrees with the standard literature.
