Large nonlinear phase shif towing to cascaded chi((2)) in quasi-phase-matched bulk LiNbO(3)

Large nonresonant effective nonlinear indices that are due to cascading have been observed by Z-scan and CCD camera measurements performed on quasi-phase-matched LiNbO(3). Positive and negative values of n(cascad)(2) were measured at temperatures symmetrically displayed with respect to the optimum phase-matching temperatures (2.39 x 10(-13) and -2.37 x 10(-13)cm(2)/W, respectively).