Abstract:A series of bismuth borate silica glasses were prepared and their densities, linear refractive indices and transmission spectra were measured. The optical gaps Eopt were obtained from the extrapolation of the linear portions to zero absorption. A decrease in the value of Eopt with increasing bismuth content may be explained by suggesting that the non-bridging oxygen ion content increases .It was found that high refractive index and narrow bandgap could lead into high third-order optical nonlinearity.
Key words:optical band gap; optical nonlinearity; bismuth oxide
Supported by the National Natural Science Foundation of China（No. 60677015）, the Science and Technology Department of Zhejiang Province （No. 20061664） and the Natural Science Foundation of Ningbo （No. 2006A610020）
NIE Qiuhua： Prof.; E-mail： firstname.lastname@example.org Corresponding author： CHEN Yanfei： E-mail： email@example.com