Three-Pulse Photon Echo Peak Shift Spectroscopy in a Dense Potassium Vapor

The three-pulse photon echo technique has provided significant insight into ultrafast dynamics in a variety of condensed phase systems1. Clear signatures of non-Markovian dynamics in a dense potassium vapor2 provide the opportunity to gain further insight into the correlation function of frequency fluctuations both experimentally and theoretically. Here, experimental three-pulse photon echo peak shifts are compared to calculated peak shifts that include the long-range resonant interactions in a dense atomic vapor within an exciton formalism3. A slow exponential decay in the peak shifts is attributed to long-range resonant interactions.