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.
