Four-wave parametric interaction in potassium vapor

Two simultaneous laser pulses incident on a cell of potassium vapor at 350°C generate an intense (1-kW) beam of violet light at about 4000 Å. The incident pulses are a 2-MW ruby beam and a 300-kW ruby-generated Stokes beam nearly resonant with the potassium 4P^3/2- 4S^1/2transition. A simplified theory is presented which treats the problem as a four-wave parametric interaction, and accounts for such experimental details as the doublet stucture of the violet light and the fact that the components of the doublet have different intensities.