Excited state absorption and energy transfer losses in thulium doped fluoroindogallate glass

Thulium doped fluoroindogallate glass was characterized by means of excited state absorption experiment in the 0.95 to 1.55 μm spectral range. The three bands corresponding to the electronic transitions ³ F ₄→³ F ₂ (at 1.05 μm), ³ F ₄→³ F ₃ (at 1.125 μm), and ³ F ₄→³ H ₄ (at 1.45 μm) were observed. The energy transfer microscopic parameters for the reverse cross relaxation process ³ F ₄, ³ F ₄→³ H ₆, ³ H ₄ were calculated for different multipolar interaction mechanisms using the Kushida model, and it was verified that the probability of this process is 100 times lower than that of the direct ³ H ₄, ³ H ₆→³ F ₄, ³ F ₄ cross relaxation, responsible for the 1.8 μm emission pumping. PACS 78.20.-e; 78.55.Qr; 42.70.Hj; 42.55.Wd