Enhanced upconversion emission of Er/Yb and Er/Yb/Zn doped calcium aluminate for use in optical thermometry and laser induced optical heating.

Title Enhanced upconversion emission of Er/Yb and Er/Yb/Zn doped calcium aluminate for use in optical thermometry and laser induced optical heating.
Authors Choudhary, A.K.; Singh, S.K.; Dwivedi, A.; Bahadur, A.; Rai, S.B.
Journal Methods Appl Fluoresc
DOI 10.1088/2050-6120/aac8f9
Abstract

There are two key factors to design an efficient green upconversion (UC) emission based optical sensor for temperature. The primary need is to develop a thermally stable and economical material, for a stable sensor, and the second essence is to get an efficient green UC emission, for high sensitivity of the sensor. The proof of this concept is demonstrated on a model system CaAlO: Er, co-doped with Yb and Zn. UC emission of Er ion is enhanced, primarily, through co-operative energy transfer from Yb to Er ions. Secondly, we prove that, incorporation of Zn ions alters local crystal field environment around Er ions which causes an enhancement in green UC emission. The variation in intensity ratio of H → I (green) and S → I (green) transitions with temperature is studied to report the sensing property. We show that, sensitivity becomes better with an increase in UC efficiency and the best sensitivity is attained for CaAlErYbZnO sample, ∼0.0154 K at 308 K. The obtained result is compared with other works and implies its better suitability. Further, the laser induced optical heating is also observed. The laser induced optical heating has been observed experimentally at 400 K above 1 W laser power. This has been further verified by theoretical justification of heating at various pump powers.

Citation Choudhary, A.K.; Singh, S.K.; Dwivedi, A.; Bahadur, A.; Rai, S.B..Enhanced upconversion emission of Er/Yb and Er/Yb/Zn doped calcium aluminate for use in optical thermometry and laser induced optical heating..