Highly efficient infrared-to-visible energy upconversion in Er3+: Y2O3

Very intense green and red emission was observed at room temperature from t he S-4(3/2) and F-4(9/2) levels of Er3+:Y2O3. A cw diode laser at 975 nm wa s used as a pump for resonant sequential excitation of the I-4(11/2) and F- 4(7/2) levels. The fluorescence was easily visible to the naked eye, even w ith 27 mW of excitation power. It was found that at 850 mm of cw excitation power the total luminance was 39,000 cd/m(2). This corresponds to similar to 100 mu W of green emission and 270 mu W of red emission. (C) 2000 Optica l Society of America OCIS codes: 160.5690, 160.2540, 260.2510, 190.7220, 17 0.6280, 020.4180.