Energy level diagram of the Nd3+ and Yb3+ ions and quantum cutting mechanism in LSCAS. Cross relaxation between Nd3+ ions Nd3+: 4F3/2→4I15/2; N3+:4I9/2→4I15/2 (CR1), and cross relaxations between Nd3+ and Yb3+ ions Nd3+:4F3/2→4I11/2; Yb3+: 4F7/2→4F5/2 (CR2) and Nd3+:4D3/2→4G7/2; Yb3+:2F7/2→2F5/2 (CR3) are depicted.
Infrared photoluminescence spectra of 1NdxYb (x = 0, 1, and 8 represented by solid, dashed, and dotted lines, respectively) LSCAS glasses. The inset shows the intensity at 1030 nm of the Yb3+ emission (the black squares) via the CR2 process as a function of the concentration of Yb3+. The Nd3+ peak intensity at 914 nm (red circles) as a function of the concentration of Yb3+ is also shown. The excitation wavelength was λexc = 514 nm, i.e., resonant with the Nd3+:4G9/2 level. The solid lines are visual guides.
Normalized infrared emission spectra in the range of 800–1500 nm for the 1Nd4Yb co-doped LSCAS glass after excitation at 325 nm and 514 nm, represented by the solid and dotted lines, respectively. The spectra were normalized at 1330 nm (4F3/2→4I13/2). For comparison, the emission at 1330 nm was 50-fold multiplied. The inset shows the relative intensity at 1030 nm as a function of the Yb3+ concentration, for both excitation wavelengths.
Nd3+:4F3/2→4I9/2 luminescence decay curves for the 1NdxYb (x = 0, 1, 2, 4, 6, and 8) LSCAS glasses detected at 914 nm after a resonant excitation with a pulsed laser (λexc = 532 nm, 5 ns). The inset shows the decay times for the Nd3+:4F3/2→4I9/2 transition at 914 nm (the black squares) and the energy transfer efficiency between Nd3+:4F3/2 and Yb3+:2F5/2 levels (the red circles). The lines are visual guides.
Kinetic response of Yb3+ DC luminescence for the 1NdxYb (x = 1, 2, 4, 6, and 8) co-doped LSCAS glasses detected at 1030 nm under excitation with a pulsed laser (λexc = 532 nm, 5 ns). The inset shows the measured probability ( ) of the CR2 and CR3 processes. The calculated of the CR3 process was performed through the subtraction . In the inset, the solid lines are visual guides.
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