Near-infrared luminescence of Er3+ doped Na0.04K0.96Y(WO4)2 single crystals

Single crystals of the compositions Na0.04K0.96Y(WO4)2 (NKYW) and x mol% Er: Na0.04K0.96Y(WO4)2 (x = 1, 3, 5, 7) (Er: NKYW) have been successfully grown by the top-seeded solution growth (TSSG) method. The growth process parameters have been investigated in detail. X-ray diffraction (XRD) and Raman spectroscopy measurements showed that the K+ and Na+ cations occupied equivalent lattice sites and the crystal structure remained monoclinic. The spectral properties and energy transfer mechanisms of the single crystals doped with different concentrations of Er3+ ions were investigated. According to the Judd-Ofelt theory, the intensity parameters of the 5 mol% Er: NKYW crystal were calculated to be Ω2 = 1.77 × 10−20 cm2, Ω4 = 3.15 × 10−20 cm2, Ω6 = 3.08 × 10−20 cm2, and the radiative transition probability of 4I13/2 → 4I15/2 was 541.25 s−1. The gain cross section of the 5 mol% Er: NKYW crystal at 1542 nm was determined to be 2.63 × 10−20 cm2, indicating that high-quality Er: NKYW single crystals have great potential for laser applications.