Determination of the absolute quantum efficiency of the luminescence from the upper active level of Nd3+ in an NdP5O14 crystal

The absolute quantum efficiency η of the luminescence from the upper active level of neodymium in an NdP₅O₁₄ crystal was determined. The result (η = 0.35 ± 0.03) indicated that it should be possible to obtain η=1 for a crystal of La_1–xNd_xP₅O₁₄ with x < 0.1.