Linear/nonlinear optical parameters of niobium-free and niobium-doped bismuth borate glass samples

Glasses of (B2O3)0.6 (CaO)0.2 (Bi2O3)(0.2−x) (Nb2O5)x were prepared utilizing a fast cooling method (where x = 0.0, 0.05 and 0.10). Fourier-transform infrared spectra FTIR revealed about shapes that characterize the amorphous solids, where broad overlapping bands were observed. Incorporation of niobium pent-oxide Nb2O5 in the glass matrix caused BO3 to BO4, an increasing glasses’ molar volume and decreasing in glasses’ opacity. Some linear and nonlinear optical parameters had been explored by means of UV–visible spectra within 200–845 nm wavelength range. The absorption coefficients, Urbach energy, direct and indirect optical band gaps increased with an increase in the niobium pent-oxide concentration, and the real linear refractive index decreased. On the other side, nonlinear refractive index, first linear and third nonlinear susceptibilities were observed to increase with increase in niobium pent-oxide.