Direct experimental observation of interactive third and fifth order nonlinearities in a time- and space-resolved four-wave mixing experiment

We have used the mechanism of Kerr lens deflection to spatially separate third and fifth order polarizations in the momentum degenerate 2k2−k1 direction for a time-resolved two pulse four-wave mixing experiment. In the far field spatially asymmetrical signals provide direct evidence of destructive interference between third and fifth order nonlinear processes. The experimental results also indicate a carrier density greater than 1016/cm3 is necessary to demonstrate exciton-exciton interaction at room temperature in GaAs bulk materials.