Concentration-dependent studies of Nd3+-doped zinc phosphate glasses for NIR photoluminescence at 1.05 μm

Nd3+-doped lead-free zinc phosphate glasses with the chemical compositions (60-x) NH4H2PO4+20ZnO+10BaF(2)+10NaF+xNd(2)O(3) (where x=0.5, 1.0, 1.5, 2.0 and 2.5mol%) were prepared using a melt quenching technique. Vibrational bands were assigned and clearly elucidated by Raman spectral profiles for all the glass samples. Judd-Ofelt (J-O) intensity parameters (: =2, 4, 6) were obtained from the spectral intensities of different absorption bands of Nd3+ ions. Radiative properties such as radiative transition probabilities (A(R)), radiative lifetimes ((R)) and branching ratios ((R)) for different excited states were calculated using J-O parameters. The near infrared (NIR) photoluminescence spectra exhibited three emission bands (F-4(3/2) level to I-4(13/2), I-4(11/2) and I-4(9/2) states) for all the concentrations of Nd3+ ions. Various luminescence properties were studied by varying the Nd3+ concentration for the three spectral profiles. Fluorescence decay curves of the F-4(3/2) level were recorded. The energy transfer mechanism that leads to quenching of the F-4(3/2) state lifetimes was discussed at higher concentration of Nd3+ ions. These glasses are suggested as suitable hosts to produce efficient lasing action in NIR region at 1.05m.