Modulation Z-scan technique in photorefractive crystals

Summary form only given. The Z-scan technique proved to be a quite simple method (it uses one laser beam only) for characterization of different optically nonlinear media. Recently this technique was also successively applied to photorefractive crystals (PRCs) Bi/sub 12/TiO/sub 20/ (BTO) under an external DC electric field. It was shown, however, that due to some point defects and inclusions that are typical for PRCs the standard Z-scan curves are characterized by a rather big spread of experimental points. Here we propose utilization of modulation version of this technique, which gives much better and more reproducible Z-scan curves in PRCs.