Degenerate four-wave mixing and Z-scan measurements of stilbazolium derivatives

Stilbazolium derivatives are very attractive optical materials for photonic s and biophotonics applications because a large number of these derivatives are available and they can exhibit large third-order nonlinear coefficient s and rapid responses. To quantitatively characterize their third-order non linear coefficients and the temporal responses of their third-order nonline ar process, we have performed degenerate four-wave mixing and Z-scan experi ments on four stilbazolium derivatives with different electron donors using 40 ps laser pulses at 532 nm. The gamma values for three of the compounds are on the order of 10(-31) esu. These high values arise from electronic pr ocesses and are associated with both nonlinear absorption and nonlinear ref raction. The relative contributions from nonlinear absorption and nonlinear refraction are dependent on the chemical structure and linear absorption o f the stilbazolium derivative. (C) 2001 American Institute of Physics.