Abstracts 2001

Abstract of Publication No. 378

S. Heer, M. Wermuth, K. Krämer and H. U. Güdel
Upconversion excitation of Cr3+ 2E emission in Y3Ga5O12 codoped with Cr3+ and Yb3+
Chem. Phys. Lett. 334, 293-297 (2001)      Full Text (PDF)      DOI-Link     

Abstract: The 2E 4A2 emission of Cr3+ in crystals and glasses is of great importance in science and technology. We report a new excitation mode for this emission in Y3Ga5O12 (YGG) codoped with Cr3+ and Yb3+. It is based on an upconversion mechanism using 2F5/2 of Yb3+ as an intermediate state. Excitation in the near-IR at 969.6 nm leads to visible luminescence around 700 nm at low temperature. In YGG:2%Cr3+,1%Yb3+ at 15 K and for a laser power of 150 mW the efficiency of the process is 5.5%. From its time dependence the upconversion mechanism is found to be dominated by an energy transfer step: Two excited Yb3+ ions simultaneously transfer their 2F5/2 excitation to Cr3+.

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