Abstract of Publication No. 450
We report on upconversion (UC) luminescence in YAlO3 codoped with
0.3% Cr3+ and 6% Yb3+. At 10 K excitation around
10,400 cm–1 leads to red Cr3+ pair luminescence at
14,000 cm–1. The UC excitation spectrum of the red Cr3+
luminescence is very similar to the squared Yb3+ absorption spectrum.
This demonstrates that two Yb3+
excitations are involved in the UC process.
From transient measurements, the UC mechanism is found to be dominated by an
energy transfer step: Two excited Yb3+ ions simultaneously transfer
their excitation energy to a nearby Cr3+ pair.