Transient four-wave mixing in saturable media with a nonlinear refractive index

We study the transient behaviour of a degenerate four-wave mixing process i n a saturable nonlinear medium where the laser induced refractive index cha nge is given by Delta n = n(2)I/(1 + I/I-s). The theoretical model we devel op can be applied for any complex value of n(2) which contains absorptive, dispersive or mixed components. This model explains very well our experimen tal results in GdAlO3:Cr3+, using n(2) and I-s values that are in good agre ement with previous measurements. (C) 1999 Elsevier Science B.V. All rights reserved.