Optical Properties of Bi2O3–TeO2–B2O3 Glasses

Glasses of the Bi2O3–TeO2–B2O3 ternary system were developed and their linear and nonlinear optical properties were investigated. The absorption edges of these glasses were found to be 367–384 nm with a good transmittance in visible wavelength, although they exhibit the refractive indices as high as 1.98–2.12 at 633 nm. The absorption edges are quite steep and they are analyzed by the Urbach theory. The obtained Urbach energies of these glasses are 73–79 meV which are comparable to silica glasses. The high refractive index and its glass composition dependency are discussed according to the basics of the electronic polarizability and optical basicity. The high third order nonlinear susceptibility χ(3) = 2.0 × 10− 12 esu at 800 nm was also obtained in the 36Bi2O3–18TeO2–46B2O3 glass.