STUDY ON UPCONVERSION FLUORESCENCE OF Er3+-DOPED YTTRIUM VANADATE

Abstract

Upconversion fluorescence near 553 and 410nm was detected when the Er3+-doped yttrium vanadate (Er3+∶YVO4) crystal was excited with a 808nm-diode laser and a 658nm-dye laser. Analysis of excitation mechanism shows that excited state absorption dominantly contributes to the upconversion emissions. Measurement of lifetimes for different Er3+ concentration indicates that the lifetime of 553nm emission decreases with increasing Er3+ concentration, but no considerable changes of that of 410nm emission have been observed. With the consideration of the fact that the intensity of 553nm band declines with increasing Er3+ concentration, we argue that in the concentration range measured there is an appreciable concentration quenching in the 553nm emission, and a dominant population channel of its upper state (4S3/2) is the nonradiative relaxation from the upper state (2H9/2) of the 410nm band.