Spectroscopic investigations of Nd 3+ doped flouro- and chloro-borate glasses

Abstract

Spectroscopic and physical properties of Nd 3+ doped sodium lead flouro- and chloro-borate glasses of the type 20NaX–30PbO–49.5B 2O 3–0.5Nd 2O 3 (X = F and Cl) have been investigated. Optical absorption spectra have been used to determine the Slater Condon ( F 2, F 4, and F 6), spin orbit ξ 4f and Racah parameters ( E 1, E 2, and E 3). The oscillator strengths and the intensity parameters Ω 2, Ω 4 and Ω 6 have been determined by the Judd–Ofelt theory, which in turn provide the radiative transition probability ( A), total transition probability ( A T), radiative lifetime ( τ R) and branching ratio ( β) for the fluorescent level 4F 3/2. The lasing efficiency of the prepared glasses has been characterized by the spectroscopic quality factor ( Ω 4/ Ω 6), the value of which is in the range of 0.2–1.5, typical for Nd 3+ in different laser hosts. Nephelauxetic effect results in a red shift in the energy levels of Nd 3+ for chloroborate glass. The radiative transition probability of the potential lasing transition 4F 3/2 → 4I 11/2 of Nd 3+ ions is found to be higher for flouroborate as compared to chloroborate glass.