Low-hydroxy Dy3+/Nd3+ co-doped fluoride glass for broadband 2.9 µm luminescence properties

Abstract The novel Dy 3+ singly doped and Dy 3+ /Nd 3+ co-doped fluoride glasses have been synthesized, and their fluorescence properties have been monitored under 808 nm excitation. The addition of Nd 3+ leads to a higher emission peak, and a longer lifetime of 270 μs for Dy 3+ 2.9 µm emission, benefited by the low OH - content(0.032 cm −1 ) host and effective energy transfer of Nd 3+ : 4 F 5/2 , 2 H 9/2 →Dy 3+ : 6 F 5/2 with a energy transfer coefficient of 3.0×10 –40 cm 6 /s. Radiative and emission parameters were calculated based on the Judd-Ofelt theory, which shows that the Dy 3+ /Nd 3+ co-doped sample possesses a high calculated spontaneous transition probability (38.3 s −1 ) together with a large emission cross section (5.22×10 –21  cm 2 ). The FWHM is as wide as 260 nm, indicating it is suitable for tunable laser medium. These results prove the fluoride glass could be used as a potential candidate for compact and efficient eye safe mid-IR lasers.