Measurements of absorption and excitation spectra for Nd3+ in soda-lime silicate glass, CaWO4, and Y3Al2(AlO4)3 (YAG) are presented. The relative quantum efficiency for 4F3/2 → 4I11/2 fluorescence is evaluated for principal absorptions over the wavelength range 3250–9300 Å. For the crystals, quantum efficiency is found to be independent of the level pumped, to within ±12% for CaWO4 and ±13% for YAG. Except for slight quenching of levels between 4000 and 5500 Å, quantum efficiency for the glass sample is independent of pumping level to within ±5%. These results indicate that the efficiency of each step in the process which populates the 4F3/2 level is near unity. Also, over the range of structures investigated, relative Nd3+ quantum efficiency appears to be independent of the details of crystal-field structure.
RICHARD A. BRANDEWIE and CHARLES L. TELK, "Quantum Efficiency of Nd3+ in Glass, Calcium Tungstate, and Yttrium Aluminum Garnet," J. Opt. Soc. Am. 57, 1221-1225 (1967)