Optimal mixing of light waves with finite spectral widths

An analysis is made of the influence of the spectral width on the process of mixing at optical frequencies. Numerical results show that, for a given length of a nonlinear crystal and a given energy of exciting waves, there are optimal widths of the spectra of the pump waves for which the energy of the combinationfrequency wave is highest. The optimal parameters depend on the length of the crystal and on the ratio of the group detunings of the interacting waves.