Four-photon resonant parametric sum-frequency generation using coherent and noise pumping in potassium vapor

An experimental investigation was made of the use of noise pumping in four-photon resonant parametric sum-frequency generation in potassium vapor. A two-photon resonance with the 9S_1/2 and 7D_3/2,5/2 levels and a one-photon resonance with the 10P_1/2,3/2 and 11P_1/2,3/2 levels were used. A comparison was made with the case of coherent pumping and it was found that, under conditions of strong dispersion and wave mismatch, the efficiency of the process using noise pumping differs negligibly from the efficiency using coherent pumping although the spectral density of the coherent pump is substantially higher than that of the noise pump.