Temperature decrease induced by stimulated emission in the Nd3+ ion-doped YAl3(BO3)4 crystal

The temperature rise induced by illumination in a (YAl3(BO3)4) crystal activated with Nd3+ luminescent ions has been measured under spontaneous and stimulated emission conditions. Due to the low-quantum efficiency (18–26%) of the Nd3+ ion in this crystal, a remarkable temperature decrease (13° at 150 mW of absorbed pump power) is observed when switching from spontaneous to stimulated emission. This `thermal coolingʹ can also be used to estimate the B Einstein coefficient. The value we have obtained, B=2.3×1014 m3 J−1 s−1 for the main laser transition, is in good agreement with those reported by other methods.