Vol.:(0123456789) 1 3 Applied Physics A ( 2020) 126:384 https://doi.org/10.1007/s00339-020-03552-z Linear/nonlinear optical parameters of niobium‑free and niobium‑doped bismuth borate glass samples Hossam Mohamed Gomaa 1,2  · I. S. Ali 1,3  · Ammar S. Morsy 1  · M. I. Sayyed 4 Received: 29 February 2020 / Accepted: 15 April 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Glasses of (B 2 O 3 ) 0.6 (CaO) 0.2 (Bi 2 O 3 ) (0.2−x) (Nb 2 O 5 ) 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 Nb 2 O 5 in the glass matrix caused BO 3 to BO 4 , 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 coefcients, 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, frst linear and third nonlinear susceptibilities were observed to increase with increase in niobium pent-oxide. Keywords Borate glass · Oxide glass · Linear optics · Nonlinear optics · Refractive index 1 Introduction Glass solids have wide consideration in many Scientifc and Technological felds, because of their applications in lasers, optical fber amplifers, fat-panel displays, optical limiting and switching devices, optoelectronic, memory devices, solar cells and light-emitting diodes [1, 2]. Generally, oxide glasses possess a large number of unique properties, like high transparency and optical damage threshold. Such prop- erties encouraged several researchers to work extensively to modify such materials to achieve strong nonlinear coef- fcients that are essential parameters for the utilization of material in nonlinear optical (NLO) devices [1–3]. Glasses containing bismuth oxide were attracted more attention than other glasses because of their high refractive indices and large transmission window in the visible and near infrared. Glasses doped with Bi 3+ cations were found to have third- order susceptibility χ 3 of maximum value around 800 nm, which indicates that solids may be used as an optical switch- ing material [4]. Elsewhere [5], it was found that the addi- tion of transition metal cations of empty d-shell like Nb 5+ cations to oxide glasses perturb the third-order susceptibility χ 3 , real-refractive index, static refractive index and optical band gap. Yanfei et al. [6] stated that the third optical nonlin- earity increase for Bi 2 O 3 –WO 3 –TeO 2 glasses with increase in the optical band gap because of WO 3 acts to increase the density of the non-bridging oxygen atoms. Vijaya stated that the optical band gap and dispersion energies of 10% Na 2 O–Nb 2 O 5 –(90 − x)% TeO 2 glasses decrease with the increase in Nb 5+ content [7]. The work aims to study the efect of replacement of Bi 2 O 3 by Nb 2 O 5 on linear/nonlin- ear optical properties of some calcium borate glasses. Such glasses were chosen based on the fact that glass should dem- onstrate high third-order optical nonlinearities and possibly fast response time. Such materials with high optical nonlin- earity have a signifcantly important role in photonics and optoelectronics technology. * Hossam Mohamed Gomaa H_goumaa@yahoo.com 1 Optical Branch, Higher Institute of Optics Technology, Cairo, Egypt 2 Higher Institute of Engineering, Automotive and Energy, New Heliopolis, Cairo, Egypt 3 Faculty of Public Health and Health Informatics, Umm Al-Qura University, Mecca City, Saudi Arabia 4 Department of Physics, Faculty of Science, University of Tabuk, Tabuk, Saudi Arabia