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

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 F-7(6)-> D-5(4) transition of Tb3+ ions, are 9.28 x 10(-22) and 4.94 x 10(-22) cm(2) for the pi and sigma polarizations, respectively. The radiative lifetime of the D-5(4) multiplet is 611 mu s? 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 D-5(4)-> F-7(5) transition of Tb3+ ions, are 8.36 x 10(-21) and 5.10 x 10(-21) cm(2) for pi and sigma polarizations, respectively. The fluorescence lifetime of the D-5(4) multiplet is 575 mu s, and quantum efficiency reaches to 94%. Above results show that the NaTb(WO4)(2) crystal is a potential gain medium for visible laser.