铒镱共掺钨酸钆钾激光晶体生长、结构及光谱特性

GROWTH,STRUCTURE AND SPECTRAL PROPERTIES OF Er^(3+):Yb^(3+):KGd(WO_4)_2 LASER CRYSTAL

采用顶部籽晶提拉法生长出铒镱共掺钨酸钆钾[Er^(3+):Yb^(3+):KGd(WO_4)_2,Er:Yb:KGW]激光晶体。这种晶体的最佳生长工艺参数为:转速为10～15 r/min,提拉速率为1～2mm/d,降温速率为0.05～0.1℃/h,生长周期为10～15d。X射线衍射分析表明,所生长的晶体为β-Er:Yb:KGW。经热重-差热分析确定:晶体的熔点为1079℃,相转变温度为1024℃。测量晶体的红外及Raman光谱,并对峰值及相应的原子基团振动进行了归属。晶体样品的吸收光谱显示:在380,52.3,935nm和981 nm处存在较强的吸收峰,主峰981 nm处的吸收截面积为3.35×10^(-20)cm^2。分别在488nm和980nm波长光激发下,均可以产生较强的1.53μm对人眼安全的激光,表明Yb^(3+)对Er^(3+)具有敏化作用,既提高了对泵浦光的吸收效率,又降低了激光振荡阈值。

Er^3＋：Yb^3＋：KGd（WO4）2（Er：Yb：KGW）laser crystal was grown by the top seeded solution growth（TSSG）method.The optimal growth conditions of the crystal were specified as follows：a rotation rate of 10-15 r/min;pulling speed of 1-2 mm/d;cooling rate of 0.05-0.1℃/h;and a growth period of 10-15 d.The crystal was identified as-Er：Yb：KGW by X-ray diffraction analysis.The transition temperature and melting point of the crystal determined by thermogravimetry-differential thermal analysis curve are 1 024℃and 1 079℃,respectively.The infrared spectra and Raman spectra of the crystal were measured,and the vibration frequencies of infrared and Raman active modes for Er：Yb：KGW crystal were assigned.The absorption spectrum of the crystal shows that there were several strong peaks at 380,523,935 nm and 981 nm,and the absorption cross section at the main peak of 981 nm is 3.35×10^（-20） cm^2.The crystal emits a strong eye-safe laser of 1.53μm emission wavelength excited with light of 488 nm and 980nm wavelengths. This indicates the sensitization effect of Yb^3＋to Er^3＋ions;therefore,the absorbance efficiency not only can be improved,but also the laser oscillating threshold value will be decreased.