中文摘要：

研究了三种掺Yb钒酸盐混晶Yb0.005：Y0.298Gd0.697VO4,Yb0.007：Y0.407Gd0.586VO4和Yb0.009：Y0.575Gd0.416VO4的室温偏振吸收谱和发射谱.结果表明,最强的吸收和发射相应于π偏振,位于波长985nm;随组分不同,最大吸收截面σabs=4.8—8.5×10-20cm2,吸收带宽9.5—9.9nm;最大受激发射截面σem=5.8—10.3×10-20cm2.利用高亮度半导体激光器纵向抽运实现了室温下的连续波激光运转.研究发现,不同混晶的激光振荡行为存在很大差异：在谐振腔输出耦合透过率T=2%条件下,Yb0.005：Y0.298Gd0.697VO4和Yb0.009：Y0.575Gd0.416VO4的激光振荡随抽运功率降低而出现σ,π偏振态的共存和转变;而Yb0.007：Y0.407Gd0.586VO4的激光振荡则保持π偏振态不变.在T=5%情形,Yb0.009：Y0.575Gd0.416VO4的激光振荡为单纯的σ偏振;而Yb0.005：Y0.298Gd0.697VO4所产生的激光振荡随抽运功率下降仍出现类似的偏振态变化行为.

英文摘要：

The room-temperature polarized absorption and emission spectra of Yb doped mixed vanadates Yb0.005：Y0.298 Gd0.697 VO4,Yb0.007：Y0.407 Gd0.586 VO4,and Yb0.009： Y0.575 Gd0.416 VO4 have been studied. The results show that the strongest absorption and emission,occurring at wavelength of 985 nm,correspond to the π polarization,depending on the composition the maximum absorption cross section ranges from 4. 8 to 8. 5 × 10-20 cm2,with bandwidths of 9. 5—9. 9 nm, whereas the maximum stimulated emission cross section varies in the range of 5. 8—10. 3 × 10-20 cm2. Continuous-wave laser operation has been realized at room temperature with the mixed crystals through longitudinal pumping with a diode laser. It was found that the laser oscillation behavior differs significantly from one mixed crystal to another：in the case of T = 2% （ T is the output coupling of the resonator）,the coexistence and switching of σ,π polarization states occur on reducing the pump power in the laser oscillation of Yb0.005：Y0.298 Gd0.697 VO4 and Yb0.009：Y0.575 Gd0.416 VO4,while the laser oscillation of Yb0.007：Y0.407Gd0.586VO4 is capable of maintaining its π polarization state. In the case of T = 5% ,however, the laser oscillation generated with Yb0.009：Y0.575 Gd0.416 VO4 is purely σ-polarized,whereas the laser behavior of Yb0.005： Y0.298Gd0.697VO4 is similar to that exhibited in the case of T=2% .