Two distinct forms of conical emission are observed when a strong near-resonant laser pulse propagates through sodium vapor. One of the cones originates in a resonantly enhanced parametric four-wave mixing process. A spatially and spectrally distinct cone is produced by the radiative decay of the coherently prepared population of the excited state at a frequency close to that of the unperturbed atomic resonance.
|Number of pages
|Journal of the Optical Society of America B: Optical Physics
|Published - Jan 1988