1.84 m emission of Tm3+ sensitized by Yb3+ ions in monoclinic KGd„WO4...2 single crystals

By exciting at 940 nm, we have characterized the 1.84 m near infrared emission of trivalent thulium ions in Yb3+, Tm3+:KGd WO4 2 single crystals as a function of the dopant concentration and temperature, from 10 K to room temperature. An overall H6 Stark splitting of 470 cm −1 for the Tm3+ ions in the Yb3+, Tm3+:KGd WO4 2 was obtained. We also studied the blue emission at 476 nm Tm3+ and the near infrared emissions at 1.48 m Tm3+ and 1 m Yb3+ as a function of the dopant concentration. Experimental decay times of the G4, H4, and F4 Tm 3+ and F5/2 Yb3+ excited states have been measured as a function of Yb3+ and Tm3+ ion concentrations. For the F4→ H6 transition of Tm3+ ions, we used the reciprocity method to calculate the maximum emission cross section of 3.07 10−20 cm2 at 1.84 m for the polarization parallel to the Nm principal optical direction. © 2007 American Institute of Physics. DOI: 10.1063/1.2433131