Energy transfer and broad-band luminescence of Nd3+-Er3+ co-doped Lithium Fluorophosphate (LFP) glasses

Nd3+-Er3+co-doped lithium fluorophosphate (NdEr) glasses with broad-band emission were made by the traditional melt quenching technique. These glasses were characterized through physical, absorption spectra, NIR luminescence properties and structural studies using XANES. The absorption spectra of this work showed an increase with the increasing concentration of Er2O3 in the glass. The Near-Infrared (NIR) luminescence spectra were obtained from several excitation sources. The energy level diagram studied the interraction process and energy transfer mechanism. The emission intensity of Er2O3 increases up to 1.5 mol%, the concentration quenching effect makes the emission 4F3/2 → 4I9/2, 4I11/2 and 4I13/2 Nd3+ intensity weaken, which means Nd3+→Er3+ energy transfer enhanced. The Judd-Ofelt (JO) theory investigations have been applied for Nd3+ ions and found that the trend follows Ω6>Ω4>Ω2. The stimulated emission cross-section is calculated in two ways: F u¨ chtbaueer Ladenburg (FL) method and Mc-Cumber theory. The decay time is found to be bi-exponential when monitored at λex = 581 nm and λem = 1061 nm. The XANES spectra of Nd LIII-edge were investigated and the absorption band showed at ∼6209.8 eV, confirming the presence of Nd3+. The XANES spectra of Er LIII-edge were investigated and the absorption band showed at ∼8362.5 eV, confirming the presence of Er3+.