Spectroscopic properties of stoichiometric NaTb(WO4)2 crystal as a gain medium for visible laser

Abstract

A stoichiometric NaTb(WO4)2 crystal was grown by the Czochralski method and polarized spectroscopic properties of the crystal were investigated at room temperature. The peak absorption cross-sections at 487 nm of the crystal, corresponding to the 7F6→5D4 transition of Tb3+ ions, are 9.28 × 10−22 and 4.94 × 10−22 cm2 for the π and σ polarizations, respectively. The radiative lifetime of the 5D4 multiplet is 611 μs? The crystal exhibits intense green emission around 548 nm under excitation at 487 nm. The peak emission cross-sections at 548 nm of the crystal, corresponding to the 5D4→7F5 transition of Tb3+ ions, are 8.36 × 10−21 and 5.10 × 10−21 cm2 for π and σ polarizations, respectively. The fluorescence lifetime of the 5D4 multiplet is 575 μs, and quantum efficiency reaches to 94%. Above results show that the NaTb(WO4)2 crystal is a potential gain medium for visible laser.