Crystal growth and spectroscopic investigations of Dy:YAlO3 and Dy,Tm:YAlO3 crystals for a??3a?ˉ??m laser application

摘要： Dy3+:YAP and Dy3+,Tm3+:YAP single crystals have been successfully synthesized by Czochralski (CZ) method aiming for ~3 μm emission. The optical absorption and emission features of both crystals were studied in detail. A narrow and weak absorption band around 800 nm as well as an upconversion emission under the excitation of 802 nm in Dy3+:YAP crystal along with a weak ~3 μm emission were observed, indicating that Dy3+:YAP crystal is not suitable for direct pumping under 800 nm excitation. Tm3+ ion was introduced as a sensitizer for enhancing ~3 μm emission and found that co-doping with Tm3+ greatly improved the absorption capacity around 800 nm. An enhanced ~3 μm emission was observed in Dy3+,Tm3+:YAP crystal under 795 nm excitation. The energy transfer mechanisms between Dy3+ and Tm3+ ions and the energy transfer micro-parameters were discussed. Higher values of microscopic energy transfer constants between Dy3+ and Tm3+ ions were obtained, proving Tm3+ ion act as an effective sensitizer for Dy3+ ion in YAP crystal. Following the obtained optical results, Dy3+,Tm3+:YAP crystal could be a promising medium for 3 μm laser operation under 795 nm laser diode for practical applications.