LAUSR

Abstract Here a strategy was proposed to realize the thermal enhancement of the green luminescence of Tb3+ ion through ground state thermal population. The 5D4-7F5 emission line of Tb3+ ion was observed under the excitation of a commonly used 405 nm laser diode for the first time, to the best of our knowledge. Its intensity was found to increase by ten times upon increasing the temperature from 343 to 783 K. Moreover, this change law was in good accordance with the Boltzmann distribution. It was confirmed that the thermal population of the 7F5 state at the expense of the depopulation of the 7F6 ground state, namely the ground state thermal equilibrium, should be responsible for this uncommon phenomenon. For comparison, the Xe lamp was also used to directly excite the 7F6 -5D3 absorption line of Tb3+ ion. In this case, the 5D4-7F5 emission line of Tb3+ ion was also observed. Different from the former case, this line decreased monotonously upon increasing the temperature over the experimental range. The reason for this change law was also discussed.