Efficient frequency upconversion of Tm(3+) ions in Yb(3+) doped barium- thorium fluoride glass

If infrared light can be efficiently changed to visible light it would have important implications for optical detection and display devices. In this paper, the efficiency of the two-photon upconversion process between Yb(3+) and Tm(3+) ions in BaF2/ThF4 heavy metal fluoride glass is investigated as a function of Tm(3+) concentration and temperature. It is found that, for the concentration of 0.05-mol pct TmF3 and a projected incident infrared intensity of 1 W/sq cm, the projected efficiency at 300 K would be 1.2 percent. (Author)