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

The novel Dy3+ singly doped and Dy3+/Nd3+ co-doped fluoride glasses have been synthesized, and their fluorescence properties have been monitored under 808 nm excitation. The addition of Nd3+ leads to a higher emission peak, and a longer lifetime of 270 μs for Dy3+ 2.9 µm emission, benefited by the low OH- content(0.032 cm−1) host and effective energy transfer of Nd3+: 4F5/2, 2H9/2→Dy3+: 6F5/2 with a energy transfer coefficient of 3.0×10-40 cm6/s. Radiative and emission parameters were calculated based on the Judd-Ofelt theory, which shows that the Dy3+/Nd3+ 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 cm2). 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.