不同组分的钒酸盐混晶Ybt:YxGd1-t-xVO4光谱与激光性质的比较研究

研究了三种掺Yb钒酸盐混晶Yb_0.005:Y_0.298Gd_0.697VO₄, Yb_0.007:Y_0.407Gd_0.586VO₄和Yb_0.009:Y_0.575Gd_0.416VO₄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,位关键词：掺Yb钒酸盐混晶吸收谱和发射谱激光振荡偏振态

Comparative study on the spectroscopic and laser properties of mixed vanadates Ybt:YxGd1-t-x VO4 with different compositions

The room-temperature polarized absorption and emission spectra of Yb doped mixed vanadates Yb_0.005:Y_0.298Gd_0.697VO₄, Yb_0.007:Y_0.407Gd_0.586VO₄, and Yb_0.009:Y_0.575Gd_0.416VO₄ 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 Yb_0.005:Y_0.298Gd_0.697VO₄ and Yb_0.009:Y_0.575Gd_0.416VO₄, while the laser oscillation of Yb_0.007:Y_0.407Gd_0.586VO₄ is capable of maintaining its π polarization state. In the case of T=5%, however, the laser oscillation generated with Yb_0.009:Y_0.575Gd_0.416VO₄ is purely σ-polarized, whereas the laser behavior of Yb_0.005:Y_0.298Gd_0.697VO₄ is similar to that exhibited in the case of T=2%.