LAUSR

Abstract Traditionally, the 980 nm laser is used as the excitation source for Yb 3 + /Er 3 + codoped phosphors. Different from this conventional way, it is shown here that the as-prepared CaWO4:Yb 3 + /Er 3 + (5/1 mol %) phosphors can be effectively triggered by the commonly used and cheap 405 nm laser diode. On such excitation, the Er 3 + ion’s characteristic green emission, which is ascribed to the 2H 11∕2 ∕ 4 S 3∕2 -4I 15∕2 transitions, is successfully detected with a good signal to noise ratio. The green emission’s response to the temperature change is investigated in the 93–813 K range. It is confirmed that the 2H 11∕2 -4I 15∕2 and 4S 3∕2 -4I 15∕2 transitions obey the Boltzmann distribution well, which are thus suitable for optical ratiometric temperature measurement. Their maximum relative sensitivity is found to be 10.41% K−1 at 93 K.