Chemical-bond analysis of the nonlinear optical properties of the borate crystals LiB3O5, CsLiB6O10, and CsB3O5

The second-order nonlinear optical properties of practical borate crystals, LiB3O5, CsLiB6O10, and CsB3O5, which all contain the identical basic structural unit [the (B3O7)5- group], have been quantitatively studied from the chemical-bond viewpoint. Differences in the nonlinear optical properties among these three borate crystals arise from the contributions of the different cations, i.e., the different interaction between the cation and the (B3O7)5- anionic group. The chemical-bond method quantitatively expresses this important difference. At the same time, the current calculation also shows that the B3O7 group is a very important crystallographic frame in the crystalline borate solids; it offers different cations an excellent coordination environment.