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1、High efficient 1.56 m laser operation of Czochralski grown Er:Yb:Sr3Y2(BO3)4 crystal,胡杰 120420164,Outline,Abstract Introduction Experiment Results and discussions Conclusion,Abstract,An Er:Yb:Sr3Y2(BO3)4crystal doped with 0.9 at.% Er3+and 18.6 at.% Yb3+ions was grown by the Czo-chralski method. End-
2、pumped by diode laser at 970 nm in a hemispherical cavity, 1.3 W quasi-cw laser output around 1.56 m was achieved in a 1.1-mm-thick Z-cut Er:Yb:Sr3Y2(BO3)4crystal when the transmission of output coupler is 1.5%. The absorbed pump threshold and slop efficiency of the laser are 4.26 W and 20%, respect
3、ively. This crystal has flat and broad gain curve peaked around 1.56m, which shows that it is also a potential gain medium for tunable and short pulse lasers.,Introduction,Erbium laser at 1.5-1.6 m via the 4I13/24I15/2 transition has many practical applications. Yb3+ ions with large absorption cross
4、-section around 980 nm, the emission wavelength of InGaAs diode laser, are generally co-doped as sensitizer to improve the pump efficiency. Er3+ and Yb3+ co-doped borate crystals, such as YAl3(BO3)4 GdAl3(BO3)4 , YCa4O(BO3)3, andGdCa4O(BO3)3 crystals have been demonstrated to be efficient gain media
5、 for the 1.5-1.6 m laser.,However, the YAB and GAB crystals can only be obtained by the flux method with a long growing period. Although the YCOB and GCOB can be grown by the Czochralski method, which is one of the techniques for growing large single crystals with good optical quality in a short per
6、iod, the peak absorption cross-sections around 976 nm of the Er3+ and Yb3+ co-doped YCOB (0.910-20cm2) and GCOB(1.15 10-20 cm2) crystals are small and the full widths at half the maximum (FWHMs) of the absorption bands are narrow. The M3Re2(BO3)4 (M=Ca, Sr, Ba; and Re=Y, Gd, La) crystals can be grow
7、n by the Czochralski method. It has been shown that Yb3+ ions doped in these crystals have larger absorption cross-section and broader absorption band around 976 nm than those of the YCOB and GCOB,Experiment,配料,研磨,烧结,生长,装炉,重复,基座,石英管,氧化锆填充料,坩埚,射频感应圈,熔体,晶体,观察孔,保温罩,提拉杆,Pull rate 12mm/h Rotate rate1020r
8、pm Annealing rate 1030C/h,Er3+/Yb3+:SYB,Results and discussions,Fig.1. RT polarized absorption spectra of Er:Yb:SYB crystal in a range of 850 1070 nm,Fig. 2. RT polarized absorption (a) and emission spectra (b) of Er:Yb:SYB crystal in a range of 14001670 nm,Fig. 3. Gain curves of the 4I13/2 4I15/2tr
9、ansition of Er3+ ions in Er:Yb:SYB crystal for E/Y with different and for E/X , E/Y and E/Z when is 0.5,Fig. 4. Laser output power at 1.5-1.6 m as a function of absorbed pump power at 970 nm,absorbed pump threshold power,4.26 W,3.9 W,1.13 W,1.3 W,Fig. 5. Spectra of the Er:Yb:SYB laser at 1.5-1.6 m w
10、hen the absorbed pump power is 10.86 W and output coupler transmissions are: (a) T=1.0%, (b) T=1.5%.,Conclusion,1.3 W quasi-cw laser output around 1.56 m with a slop efficiency of 20% was achieved in Er:Yb:SYB crystal grown by the Czochralski method. By means of the intracavity frequency doubling te
11、chnique, the linearly polarized 1.56 m laser can be further effectively converted into 780 nm laser, which has some important applications as mentioned above. It is worth noting that the absorption cross-section of the Er:Yb:SYB crystal at 976 nm is twice as that at the pump wavelength of 970 nm in
12、this work (see Figure 1) Therefore, if a pump source around 976 nm is used, the laser performance of a thinner Er:Yb:SYB medium could be improved. Furthermore, large single Er:Yb:SYB crystal can be growth easily in a short period via the Czochralski method. Combining with the suitability for diode pumping, flat and broad gain curve, and good laser performance, it can be concluded that this crystal is a potential gain medium for tunable and short pulse laser around 1.56 m.,
