  Optical oscillators present a powerful optimization mechanism. The inherent
competition for the gain resources between possible modes of oscillation
entails the prevalence of the most efficient single mode. We harness this
'ultrafast' coherent feedback to optimize an optical field \emph{in time}, and
show that when an optical oscillator based on a molecular gain medium is
synchronously-pumped by ultrashort pulses, a temporally coherent multi mode
field can develop that optimally dumps a general, dynamically-evolving
vibrational wave-packet, into a \emph{single vibrational target state}.
Measuring the emitted field opens a new window to visualization and control of
fast molecular dynamics. The realization of such a coherent oscillator with hot
alkali dimers appears within experimental reach.
