The unsteady generation of sum frequency with a phase-modulated ultrashort laser pulse

Theoretical results are presented concerning the unsteady generation of sum frequency by an ultrashort laser pulse with allowance for phase modulation; the dispersion of the nonlinear medium is taken into account in the second approximation. It is shown that the phase modulation leads to spectrum broadening and a decrease in the energy of the excited frequency. The maximum energy of the excited frequency and thus of the conversion efficiency is attained at finite values of the quasi-static length and the spreading length.