Growth and spectra properties of Tm, Ho doped and Tm, Ho co-doped CaGdAlO4 crystals

Growth of Tm, Ho doped and Tm, Ho co-doped CaGdAlO4 crystals by Czochralski method are investigated for the first time. Tm:CaGdAlO4 crystal without any crack was obtained. The segregation coefficient and XRD were detected and the results revealed that the cell parameters decreased with increasing of the doping concentration. The absorption spectra, J-O parameters, emission spectra and fluorescence lifetime of were discussed. The absorption cross sections were calculated to be 0.61×10−20 cm2 and 1.49×10−20 cm2 at 793 nm and 798 nm for a polarization and c polarization of Tm:CaGdAlO4 crystal, and the stimulated emission cross-section was calculated to be 0.36×10−20 cm2 at 1762 nm. The stimulated emission cross-section of Ho:CaGdAlO4 crystal was calculated to be 1.18×10−20 cm2 at 2002 nm. The width of Tm,Ho:CaGdAlO4 emission band is almost 600 nm. The results show that Tm:CaGdAlO4, Ho:CaGdAlO4 and Tm,Ho:CaGdAlO4 crystals were excellent potential ultrafast laser media.