RED TO BLUE UP-CONVERSION EMISSION OF TM3-DOPED GLASS-CERAMIC( IONS IN YB3+)

A detailed study of the spectroscopic properties of PbF2 + GeO2 + WO3 glass ceramics doped with Tm3+ and codoped with Tm3+ and Yb3+ ions upo n 680 nm dye laser light excitation has been made. The absorption, up- conversion emission, excitation, and time-resolved spectra were measur ed as a function of TmF3 and YbF3 concentrations at room temperature. An enhancement of blue emission centered at 478 nm in the codoped samp le was observed. The optium concentrations of TmF3 and YbF3 for this b lue emission are about 0.2 and 15 mol %, respectively. It is suggested that the results are due to energy transfer between Yb3+ and Tm3+ ion s. Measured oscillator strengths and radiative rates for several trans itions are compared with calculated values using the Judd-Ofelt theory with reasonable agreement between theory and experiments for sample d oped with Tm3+ ions.