Journal of Physics B Atomic Molecular and Optical Physics
Four-wave mixing and parametric four-wave mixing near the 4P 4S transition of the potassium atom
M. Katharakis, Nikolaos Merlemis, Alexander A. Serafetinides, Thomas Efthimiopoulos
Abstract
Potassium 4S 1/2 –6S 1/2 two-photon excitation initiates the emission of several internally generated photons. For the first time two emission lines, one close to and one below the potassium 4P 3/2 level, are reported for low pumping intensity. Radiation emitted below the 4P 3/2 level is due to a parametric four-wave mixing process that uses the photons emitted at the 5P 3/2 –4S 1/2 transition and a two-step four-wave mixing process generates the line emitted close to the 4P 3/2 level.