Optical properties of Pr 3+, Sm 3+ and Er 3+ doped P 2O 5–CaO–SrO–BaO phosphate glass

Abstract

In this paper, we present the photoluminescence properties of Pr 3+, Sm 3+ and Er 3+ doped phosphate glasses. Optical absorption and emission spectra of lanthanide active ions in P 2O 5–CaO–SrO–BaO glass have been investigated at room temperature. These glasses have shown strong absorption bands in the near-infrared (NIR) and visible (VIS) region. For Pr 3+ doped glass, emission bands centered at 608 nm ( 3P 0 → 3H 6 + 1D 2 − 3H 4), 640 nm ( 3P 0 → 3F 2), 686 nm ( 3P 0– 3F 3) and 723 nm ( 3P 0 → 3F 4) have been observed with 480 nm ( 3H 4 → 3P 0) excitation wavelength. Of them, 686 nm has shown bright red emission. Emission bands of ( 4G 5/2 → 6H 5/2) 560 nm, ( 4G 5/2 → 6H 7/2) 600 nm and ( 4G 5/2 → 6H 9/2) 645 nm for the Sm 3+ phosphate glass, with excitation at ( 6H 5/2 → 4F 7/2) 400 nm have been recorded. With regard to the Er 3+ phosphate glass, a bright fluorescent green–yellow emission at 546 nm ( 4S 3/2 → 4I 15/2) have been observed. Analysis of decay curves of luminescence revealed occurrence of the strong luminescence quenching originating from the 3P 0 metastable level of Pr 3+ and 4S 3/2 state of Er 3+ mainly by a multiphonon relaxation processes to 1D 2, 4F 9/2 levels respectively. Moreover these results are compared with those obtained by using the Judd–Ofelt theory. According to the Judd–Ofelt theory, the Judd–Ofelt intensity parameters Ω 2,4,6 were calculated, by which the radiative transition probabilities and radiative lifetimes of luminescent levels were obtained.