摘要
从Yb3+∶KGd(WO4)2(KGW)的吸收谱和荧光谱出发,利用倒易理论计算其各个光谱参量,如吸收截面,受激发射截面,辐射寿命等。由于Yb3+∶KGW晶体较适合用作二极管泵浦的激光器的材料,而激光二极管所发出的光是偏振光,晶体又是双折射晶体,因此研究了泵浦光的不同通光方向和偏振方向对Yb3+∶KGW晶体荧光光谱的影响。实验表明在不同情况下其对晶体荧光强度影响较大,因此在设计用激光二极管泵浦的激光器时,应考虑合适的泵浦光偏振方向和入射在晶体上的轴向,其中泵浦光的通光方向比泵浦光偏振方向对晶体的荧光强度的影响更大。对按晶轴切割的这两种晶体,相同实验条件下,荧光强度Ic>Ib>Ia。对于按折射率主轴切割的来说,荧光强度INp>INg>INm。在通光方向为c轴,偏振方向平行b轴时得到了最大的荧光强度。
KGd （WO4）2 laser crystal is a new laser substance material developed upon CaWO4 crystal. Regardless operated in freedom, Under control of Q value or LD pumping, it shows high efficiency. It has good mechanism and optics behave, and can be high-doped . It has potential in non-linearity and Raman scatter area. So the crystal supposes to be premising substance in the field of medical treatment, communication, electronics, remote sensing, industry and so on . Yb ion doping into this kind crystal can be used as femtosecond laser material. Now it gets many attention and became a research hotspot.
The absorption spectra and fluorescent spectra of Yb^3＋ ： KGW laser crystal were measured. From the absorption spectrum of Yb^3＋ ： KGW at room temperature, absorption peaks were found in the range from 900 to 1 050 nm, with three main peaks, 982,954 and 936 nm. The 982 nm peak is the strongest absorption peak, which can match the emission wavelength of InGaAs LD. It means this kind crystal is suitable for LD pumping.
Form the fluorescent spectrum,four fluorescent peaks, 982,998,1 017 and 1 036 nm were found. The 982 nm is the strongest fluorescent peak but also strongest absorption peak, so the laser emission in this wavelength can＇t be realized but the wavelength of 1 017 and 1 036 nm can do it.
Form the absorption and fluorescent spectrum ,the value of stark energy spit was make out, with 10 682, 10 471, 10 188 cm^-1 in up-level and 535,358,163,0 cm^-1 in the down-level.
Using Reciprocity method, the absorption cross-section, emission cross-section and fluorescent lifetime were calculated.
The absorption cross-section is large,with the value of 1. 437 × 10 ^-19 cm^2 ,this means Yb^3＋ ： KGW is tion of pumping light. The value of emission cross-section is 2. 444 × 10^-18 cm^2 and it can used for laser emission. This crystal has longer fluorescent lifetime of 0.306 ms, benefit for energy storage. Because KGW is double-axis crystal, has different character in each direction. The paper emphasize on the influence of this identity to its spectrum behave, take it suit for LD puming into account. The infection of palarization direction and incidence direction of pumping light to crystal fluorescent spectra were measured, it may be theory basis for design LD pumping solid laser.
It was found that every state is different. So when LD pumping such laser crystal was designed, the incidence and polarization direction should be taken into account. The influence of the incidence direction seems stronger than that of the polarization direction. The fluorescent intension with different incidence direction is Ic 〉 Ib 〉 Ia and INp 〉 INg 〉 INn. When light incidence is in c axis and the polarization is parallel b axis, the flurescent intension is the strongest.
出处
《发光学报》
EI
CAS
CSCD
北大核心
2007年第3期367-372,共6页
Chinese Journal of Luminescence
基金
福建省教育厅基金资助项目(JA03181
JB05310)
作者简介
吕少珍（1981-），女，福建三明人，硕士研究生，主要从事激光光谱学的研究。
通讯联系人；E-mail：7830805@citiz．net，Tel：13338433396
