  Monitoring the fluorescent radiation of an atom unravels the master equation
evolution by collapsing the atomic state into a pure state which evolves
stochastically. A robust unraveling is one that gives pure states that, on
average, are relatively unaffected by the master equation evolution (which
applies once the monitoring ceases). The ensemble of pure states arising from
the maximally robust unraveling has been suggested to be the most natural way
of representing the system [H.M. Wiseman and J.A. Vaccaro, Phys. Lett. A {\bf
250}, 241 (1998)]. We find that the maximally robust unraveling of a resonantly
driven atom requires an adaptive interferometric measurement proposed by
Wiseman and Toombes [Phys. Rev. A {\bf 60}, 2474 (1999)]. The resultant
ensemble consists of just two pure states which, in the high driving limit, are
close to the eigenstates of the driving Hamiltonian $\Omega\sigma_{x}/2$. This
ensemble is the closest thing to a classical limit for a strongly driven atom.
We also find that it is possible to reasonably approximate this ensemble using
just homodyne detection, an example of a continuous Markovian unraveling. This
has implications for other systems, for which it may be necessary in practice
to consider only continuous Markovian unravelings.
