Ultrafast spectroscopy of a dense potassium vapor

Time-integrated and time-resolved four-wave mixing spectroscopy with two and three pulses is used to study ultrafast dynamics in a dense potassium vapor. Fits based on the stochastic theory compare well with two-pulse time-integrated four-wave mixing results. The three-pulse time-integrated photon echo peak shift reveals bi-exponential behavior at high temperatures and densities not modeled by the stochastic theory. Time-resolved three-pulse four-wave mixing experiments exhibit photon-echo-like behavior.