Large third-order optical nonlinearity in Cu-doped SrBi2Nb2O9 thin filmsK. S. Chen, H. S. Gu, W. Q. Cao, J. S. Zou, L. Wang and Y. HuangEur. Phys. J. Appl. Phys., 40 1 (2007) 65-69DOI: https://doi.org/10.1051/epjap:2007122