Abstract

There is much interest in new solid-state laser materials, and materials which are codoped with two ions, one to absorb the pump radiation (donors) and the other to lase (acceptors), are of special importance. Energy transfer and frequency upconversion play important roles in these systems. Efficient upconversion has been observed in the fluoride glasses and crystals. For example, the 1.5-μm upconversion efficiency of the ⁴I_11/2 emission from the fluoride glass with 4 mol % ErF₃ is over 10% for an absorbed light intensity of 400 W/cm₂. This high efficiency could play either a useful or a detrimental role for the formation of efficient laser systems. This paper reviews energy transfer and frequency upconversion processes in fluoride glasses.

© 1994 Optical Society of America