1. For general reviews on nonlinear optics see:Nonlinear Optical Properties of Organic Molecules and Crystals, D. S. Chemla and J. Zyss (Eds.), Academic Press, New York, 1987, andNonlinear Optical Properties of Organics and Semiconductors, T. Kobayashi (Ed.), Springer Proceedings in Physics, Vol. 36, Springer-Verlag, 1989.
2. De Martinoet al.:EPO 321 891, 1988.
3. Yongqiang Shi, William H. Steier, Mai Chen, Luping Yu and Larry R. Dalton:OSA Annual Meeting, San José, 1991.
4. M. Eich, B. Reck, D. Y. Yoon, C. G. Wilson and G. C. Bjorklund:J. Appl. Phys. 66, 3241 (1989).
5. D. Jungbauer, B. Reck, R. Twieg, D. Y. Yoon, C. G. Wilson and J. D. Swalen:Appl. Phys. Lett. 56, 2610 (1990).