Temperature dependence of upconversion fluorescence intensity ratio of Er,Yb:YVO4 and Er,Yb:YGdVO4 crystals

Green upconversion fluorescence of Er,Yb:YVO
₄
and Er,Yb:YGdVO
₄
are studied in the spectral range of 520-560 nm in the temperature range from room temperature to 150°C under 967 nm pumping. It is shown that the temperature measurement sensitivity of fluorescence intensity ratio sensors on the base of these crystals is about 0.008 K
^-1
and is comparable with the corresponding values for Er-doped silica fiber.