First Achievement of Yellow Laser Operation in Dy³⁺-Doped Borate Crystals

Continuous-wave (CW) yellow lasers have been demonstrated successfully by using a GaN laser-diode (LD) pumping in borate crystals for the first time. The Dy 3+:GdMgB 5 O 10 (Dy:GMB) crystal with dimensions up to 33 × 19 × 15 mm 3 is grown by the top-seeded solution growth method, and the polarized spectroscopic properties are investigated systematically at room temperature. The line strengths, Judd–Ofelt (J–O) intensity, spontaneous transition rates, fluorescence branching ratios, and radiative lifetimes are calculated in detail by the Judd–Ofelt theory. Under direct pumping of 452 nm LD, a compact continuous-wave yellow laser with a maximum output power of 628 mW and laser wavelength of 581 nm is generated based on a Y -cut Dy:GMB crystal. To our knowledge, it is not only the highest output power for yellow laser obtained in Dy 3+ -doped crystals but also the first yellow laser operation achieved by borate crystals under direct LD pumping. The results reveal that the Dy:GMB crystal is an optical material with important application prospects in yellow laser.