Energy transfer from Tm3+ to Er3+ in zirconiumfluoride glasses pumped by a 786 nm laser diode

Abstract

The upconversion of 786 nm to visible fluorescence was studied for Tm3+ and Er3+ in both Tm3+-Er3+-codoped and Er3+ singly doped ZrF4-based fluoride glasses for several dopant concentrations. It was found that the addition of Tm3+ enhanced the upconversion efficiencies of the green and the red emission corresponding to the transitions from the4S3/2 and4F9/2 levels of the Er3+ion. The increase in the emission of samples containing 2 mol% TmF3 and 1.5 mol% ErF3 amounted to a factor of about 3 for the green emission and a factor of 300 for the red emission. The 1.48 μm emission from the transition of3F4 to3H4 for the Tm3+ ion decreased with increasing Er3+ concentration. The mechanism of the energy transfer from Tm3+ to Er3+ was discussed. ？ The Japan Society of Applied Physics.