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The Yb3+ laser emitting at a 1.03μm wavelength has been evoking strong interest recently due to its advantages of long fluorescence lifetime, broad absorption band and the fact that it never shows concentration quenching. On the other hand, as a laser of three-level system it has, in general, a relatively high threshold power, which makes it important to seek some suitable host crystals to reduce this. Here, we present a comparison of the lasing performances of Yb3+-doped YAG [Y3Al5O12], FAP [Ca5(PO4)3F] and KYW [KY(WO4)2] crystals, including threshold power and slope efficiency, with those of the Nd:YAG laser based on the threshold formula of three-and four-level systems deduced by the authors. The results show that the Yb3+ laser can output a power larger than the Nd:YAG laser does in the case of comparably higher pumping power, if the length of the lasing rod and the concentration of the active ions satisfy some conditions. The theoretical results are also close to the experimental results reported. 相似文献
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本文工作中用LHPG生长Ho:YAG,(Ho,Cr):YAG,Cr:YAG等单晶光纤。在室温下测试了这些单晶光纤的吸收谱、荧光谱、荧光寿命等光谱参数。通过荧光寿命分析了Cr→Ho和Hb→Cr之间的能量转移过程及能量转换效率η,并通过荧光衰减曲线的计算机拟合,计算了Ho→Cr之间的微观相互作用参数CDA。 相似文献
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作者测试了Cr^3+,Tm^3+和Ho^3+离子在YAG晶体中的吸收谱、荧光谱及荧光衰减寿命。计算了Cr^3+向Tm^3+和Ho^3+及Tm^向Ho^3+的能量转移效率。在(Cr,Tm,Ho):YGA晶体中由于加入Cr^3+,Tm^3+离了,使Ho^3+离子被敏化、荧光强度增大。(Cr,Tm,Ho):YAG晶体是制作-2μm(^5I7-^5I8)波长激光的优质晶体。 相似文献
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YAG晶体中Cr~(3+)→Tm~(3+),Er~(3+)→Tm~(3+)的能量 总被引:1,自引:1,他引:0
研究了加入敏化离子Cr3+和Er3+的Tm:YAG晶体的吸收谱和荧光谱,计算了Cr3+、Er3+、Tm3+离子的2E、4I13/2、3F4能态的平均寿命及能量;转移效率、转移速率.得出Cr3+→Tm3+转移效率为80%,转移速率为2.1×103s-1.由(Er,Tm):YAG的荧光谱可见存在Er3+→Tm3+的有效的能量转移.讨论了Cr3+→Tm3+和Er3+→Tm3+能量转移的不同. 相似文献
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作者用燃烧法制备了8nm-50nm的系列纳米晶Y2O3:Eu3+,利用XRD谱确定了纳米晶的晶体结构及晶粒大小。利用两套由不同波长的激光所激发的拉曼光谱,指认了纳米晶Y2O3:Eu3+的拉曼振动模,研究其拉曼光谱。与传统的拉曼光谱学相比较,光谱呈现出明显的反常,其一,是斯托克斯与相对应的反斯托克斯谱峰波数不相等;其二,随晶粒的减小,拉曼谱有明显的变化,包括谱峰的微移、半高宽的增加,以及谱峰强度比的强烈变化;其三,随着激发波长的变化,光谱也呈现出峰位移动的明显变化。这些反常的散射光谱的变化源于纳米结构的本征缺陷。 相似文献
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The absorption spectra of Tb,Tm:YVO_4 and Ho,Tm:YVO_4 are measured. The radiant and non-radiant transition probabilities from higher level to lower level, A_{i,j} and ω_{i,j}, and the cross-elaxation probability are calculated in virtue of Judd-Ofelt and Dexter theories. The fluorescence lifetime of Tm^{3+} in the Tb^{3+} (or Ho^{3+}) co-doped crystal is calculated. It indicates that the lifetime of initial level {}^3H_4 of the laser transition can be shorter than that of terminal level {}^3F_4 of the transition if the atomic percentage of Tb^{3+} (or Ho^{3+}) ions is bigger than about 1 at%: namely, by means of the co-doping Tb^{3+} (or Ho^{3+}) ions the self-termination phenomenon of laser light can be eliminated. Inserting the optic parameters to the formula deduced here on the laser threshold power P^{(4)}_{th} and the slope efficiency η^{(4)}_s of the four-energy-level system, we obtain the relationship of threshold power P^{(4)}_{th} to the concentration of Tm^{3+} ions and discuss the effect of Tb^{3+} (or Ho^{3+}) ion concentration on the laser threshold power P^{(4)}_{th} around 1.5μm wavelength. The result shows that Tb,Tm:YVO_4 crystal is a better choice to make the laser at ~1.5μm wavelength than Ho,Tm:YVO_4 crystal. We give the appropriate composition of (1-2) at% Tb, (1-2) at% Tm:YVO_4, just for reference. 相似文献