Intense 2.9 µm mid-infrared emission from Dy3+/Yb3+：SrF2 crystal under 975 nm excitation

Abstract

The intense 2.9 µm MIR (mid-infrared) luminescence corresponding to the Dy 3+ : 6 H 13/2 → 6 H 15/2 transition was achieved for the first time in Dy 3+ /Yb 3+ ions co-doped SrF 2 crystals. 2 at% Dy 3+ : SrF 2 ，2 at% Dy 3+ /5 at% Yb 3+ : SrF 2 , and 5 at% Yb 3+ : SrF 2 crystals were grown by Bridgman method. The influence of Yb 3+ on its spectral properties and energy transfer mechanisms has been studied. In comparison to Dy 3+ doped SrF 2 crystals, Dy 3+ /Yb 3+ co-doped crystals exhibit not only intense 2.9 µm emission but also longer high laser energy level lifetimes, favoring 2.9 µm population inversion and lasing behavior. Furthermore, the ET efficiency from Yb 3+ to Dy 3+ in Dy 3+ /Yb 3+ co-doped crystals is found to be as high as 95.34%, indicating that the ET from Yb 3+ is efficient. The results show that incorporating Yb 3+ into Dy 3+ : SrF 2 crystals improves the ability to achieve 2.9 µm lasing action, which could be used as a potential gain media for laser diode-pumped MIR lasers. • The Dy 3+ , Dy 3+ /Yb 3+ and Yb 3+ doped SrF 2 single crystals were grown by the Bridgman-Stockbarger method. • Intense 2.9 µm mid-infrared emission is observed in Dy 3+ /Yb 3+ : SrF 2 crystal under 975 nm excitation. • Detailed spectroscopic properties and energy transfer mechanisms were studied. • Dy 3+ / Yb 3+ : SrF 2 crystals are expected to achieve mid-infrared laser output.