Polarized spectral properties and 1.5–1.6 μm laser operation of Er:Sr3Yb2(BO3)4 crystal

• An Er3+-doped Sr3Yb2(BO3)4 crystal was grown by the Czochralski method.
• Polarized spectral properties of the Er:Sr3Yb2(BO3)4 crystal were investigated.
• Quasi-CW 1.55 μm laser of 0.75 W was obtained in the crystal.
• 1.55 μm Er3+ laser in a ytterbium stoichiometric crystal was first realized.

Undoped and Er3+-doped Sr3Yb2(BO3)4 crystals were grown by the Czochralski method. Room temperature polarized spectral properties of the Er:Sr3Yb2(BO3)4 crystal were investigated. The efficiency of the energy transfer from Yb3+ to Er3+ ions in this crystal was calculated to be about 95%. End-pumped by a diode laser at 970 nm in a hemispherical cavity, a 0.75 W quasi-CW laser at 1.5–1.6 μm with a slope efficiency of 7% and an absorbed pump threshold of 3.8 W was achieved in a 0.5-mm-thick Z-cut crystal glued on a 5-mm-thick pure YAG crystal with UV-curable adhesive.