Intense 2.9 µm emission corresponding to Dy3+:6H13/2 → 6H15/2 transition in Yb3+/Dy3+ codoped CaYAlO4 crystal

Abstract

Intense 2.9 µm emission corresponding to Dy3+:6H13/2 → 6H15/2 transition was achieved in Yb3+/Dy3+ codoped CaYAlO4 crystal for the first time. The effects of Yb3+ on the spectroscopic properties and energy transfer mechanisms were investigated. In comparison with Dy3+ singly-doped CaYAlO4 crystal, Yb3+/Dy3+ codoped crystal not only has intense 2.9 µm emission, but also has longer upper laser level lifetime, which facilitates particle number inversion and laser behavior in 2.9 µm. Furthermore, the energy transfer efficiency from Yb3+ to Dy3+ in Yb3+/Dy3+ codoped crystal was as high as 87.3%, indicating effective energy transfer of Yb3+. Besides, the energy transfer microscopic parameters between Yb3+ and Dy3+ were theoretically analyzed. The results indicate that the introduction of Yb3+ is very beneficial for achieving 2.9 µm laser in Dy3+: CaYAlO4 crystal, which could act as a potential gain media for LD pumped mid-infrared laser.