Transient degenerate two-wave mixing is investigated in isotropic media by using picosecond pulses. Efficient two-wave mixing requires that the response time of the optical nonlinearity and the duration of the laser pulses be comparable. The magnitude and the direction of the energy transfer that are due to the coherent coupling of pump and probe are found to depend on the relative delay of the two pulses, the input intensity ratio, and the polarization of the pulses. The energy transfer can occur between equal-intensity input pulses, provided that one of the pulses is delayed with respect to the other. 1992 Optical Society of America.
