Optimizing yellow fluorescence in Dy3+:SrF2 crystal through Gd3+ co-doping

A high-quality Dy3+/Gd3+: SrF2 single crystal has been grown successfully by the Bridgman method. The spectroscopic properties of the crystal have been analyzed in detail following the absorption, emission, and decay time measurements. In the Dy, Gd: SrF2 crystal, the absorption cross-section (0.83 × 10−21 cm2) at 452 nm and the emission cross-section (0.90 × 10−21 cm2) at 572 nm of Dy3+ ion are enhanced by nearly 1.5 and 3.8 times respectively, compared to Dy: SrF2 crystal. There observed a resonant energy transfer between Gd3+ and Dy3+ ions, and the yellow emission of Dy3+ ions with a peak at 572 nm was identified under 274 nm excitation. The Gd3+ ion can sensitize the emission of Dy3+ ion in the yellow region under ultraviolet (UV) light excitation. Obtained results imply that Dy, Gd: SrF2 crystal can be a potential candidate for an all-solid-state yellow laser pumped by a blue InGaN laser diode or UV laser.