UP-CONVERSION FLUORESCENCE DYNAMICS OF TM3+ IONS IN LIYF4 CRYSTAL

According to Judd-Ofelt parameter calculation and energy transfer theo ry, the cross-relaxation process of the Tm3+ ions is investigated. A f our-level system of coupled rate equations is established to study the fluorescence dynamics of Tm3+ in LiYF4 crystal. Attentions are focuse d on the upconversion luminescence (1)G(4) --> H-3(6) (483.0 nm) in Tm 3+:LiYF4. The relationship between the avalanche properties (critical pump rate, fluorescence intensity and buildup time) originated by reso nant excited state absorption and the doped Tm3+ concentration is disc ussed, and some useful conclusions are drawn.