Optical constants and related electronic energy bands of lithium triborate crystal in the 6-12-eV region

Reflectance of lithium triborate crystal in the 6-12-eV region is measured with synchrotron radiation, and the principal values of optical constants are derived. Six absorption peaks are found in both X-and Y-polarized spectra. Among them the five transitions of the Y-polarized peaks and three of the X-polarized peaks are identified. The measurement suggests that the energy of the lowest conducting band 4A(2) is 7.3 eV rather than 7.57 eV, as previously reported. (C) 1998 Optical Society of America.