Study on structural, optical and gain properties of 1.2 and 2.0 μm emission transitions in Ho3 + doped tellurite glasses

Abstract Holmium (Ho 3 + ) ions doped tellurite (TBZLN) glasses in the chemical composition (78 − x)TeO 2  + 4.5Bi 2 O 3  + 5.5ZnO + 10.5Li 2 O + 1.5Nb 2 O 5  + xHo 2 O 3 where x = 0.05, 0.1, 0.5, 1.0, 1.5 mol% were prepared by melt quenching technique and a detailed study on spectroscopic properties were reported. The characterization of prepared glasses was realized by optical absorption, fluorescence, decay profiles, X-ray diffraction (XRD), differential thermal analysis (DTA), Raman and Fourier transform infrared (FTIR) spectroscopic techniques. Absorption spectra have been analyzed by using Judd–Ofelt (J–O) theory and estimated intensity parameters, Ω 2 , Ω 4 and Ω 6 , are compared with other reported glasses. The radiative properties such as radiative transition probabilities (A rad ), branching ratios (β) and radiative lifetimes (τ R ) for certain excited states of Ho 3 + ion are calculated by using intensity parameters. The NIR and visible emission spectra were used to estimate the stimulated emission cross-sections for 5 I 7  →  5 I 8, 5 F 4 ( 5 S 2 ) →  5 I 5 , 5 I 6  →  5 I 8 , 5 F 4 ( 5 S 2 ) →  5 I 6 , 5 F 5  →  5 I 8 and 5 F 4 ( 5 S 2 ) →  5 I 8 transitions. Decay curve analysis was reported for 5 I 6 , 5 F 4 ( 5 S 2 ) and 5 F 5 levels of Ho 3 + ions. Gain coefficient was calculated for 5 I 6  →  5 I 8 and 5 I 7  →  5 I 8 transitions which arise at 1.2 μm and 2.0 μm, respectively. The analysis of present studied glasses suggests that 1.0 mol% Ho 3 + doped TBZLN glass exhibits relatively better lasing properties than other reported glasses and is favorable for photonic applications.