958 resultados para YB-YAG


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用温度梯度法(TGT)生长了大尺寸的Nd:YAG激光晶体,测试了室温下的吸收谱并利用吸收谱研究了Nd离子在YAG晶体中的分布。比较了温度梯度法与提拉法生长晶体的区别。根据热容激光的原理,利用生长的Nd:YAG激光晶体片设计了热容激光器,利用侧面抽运,获得了1200w的激光输出,工作时间为2s,光-光转换效率为30%。

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报道了以掺Yb介质硅酸镥钇晶体为增益介质的激光行为。在自由运转的条件下,在1086nm的中心波长处用2.5%的输出耦合镜得到7.8W的连续激光输出,相应的斜效率为64%。利用SF14棱镜作为腔内调谐元件,激光输出的调谐范围为1014-1091nm。

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近年来,掺Yb离子的晶体备受关注:掺Yb离子晶体能级结构简单,可以避免激发态再吸收、频率上转换、弛豫振荡和浓度猝灭等效应。此外,掺Yb离子晶体的吸收光谱位于900~1000nm,无需严格的温度控制即可与InGaAs激光二极管有效耦合,并且具有很宽范围的荧光发射谱,因此这种晶体很有潜力成为1gm波段的宽调谐及超快激光光源。

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作为发射在1μm波段的二极管抽运全固态激光器的增益介质,掺Yb离子的晶体备受关注。掺Yb晶体具有能级结构简单,量子缺陷低(〈0.1),量子效率高等优点。目前成功使用掺Yb的晶体作为增益介质的飞秒激光振荡器已有很多报道,如Yb:BOYSE,Yb:KYW,Yb:SYSE等。

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作为1μm附近由激光二极管直接抽运的高效、紧凑固体激光器的增益介质,掺Yb^3+离子的激光材料越来越受到人们的关注。掺Yb的晶体具有能级结构简单,荧光寿命长,量子缺陷低等优点。掺Yb离子的激光晶体作为增益介质的飞秒激光振荡器国际上已有报道,实现全固态飞秒激光器件的实用化是国内外科学家追求的目标。

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报道了一个激光二极管(LD)抽运多波长连续输出的激光器和一个被动调Q的固体激光器。该激光器的增益材料是一种新型掺Yb^3+的晶体Yb^3+:Lu2SiO5(Yb^1LSO)。当吸收的抽运功率为2.57W时,连续输出的最大功率为490mW,斜率效率为22.2%,光-光转换效率为14.2%,激光阈值为299mW,输出激光波长为1084nm。多波长输出时,波长调谐范围为1034~1085nm。利用InGaAs可饱和吸收镜实现调Q输出时,斜率效率为3.0%,激光波长为1058nm。脉冲重复频率为25~39kHz,

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近年来Nd:YAG多晶陶瓷作为激光介质得到了越来越多的重视,我国在这个方向也开展了大量的研究工作,Nd:YAG多晶陶瓷与Nd:YAG单晶相比有很多优点:容易制造、成本低、可以制造大尺寸和高掺杂浓度的材料,且无浓度梯度,机械特性良好,硬度比单晶大1.5倍,断裂韧度比单晶大5倍,并且可制备多层和多功能的陶瓷结构、可大批量生产,已经获得了比Nd:YAG单晶更高的效率,因此钇铝石榴石透明陶瓷是理想的钇铝石榴石单晶激光介质材料替代品。但国产陶瓷由于质量不佳,透明度不是很高,一直未能获得激光输出。

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Growth-induced defects in Yb:FAP crystals grown by the Czochralski method have been investigated by optical microscopy, chemical etching, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). Anisotropic etching features have been observed on two FAP crystal planes: (0001) and (1010). The shape of etch pits on the (0001) plane is hexagonal, while the etch pits on the (1010) plane have a variety of irregular shapes. It is also found that the density of etch pit varies along the boule. Based on the experimental observations, the formation mechanisnis of growth defects are discussed, and methods for reducing the growth-induced defect concentration is proposed. (c) 2005 Elsevier B.V. All rights reserved.

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应用中频感应提拉法生长出不同掺杂浓度的Yb:FAP激光晶体,运用电感耦合等离子体原子发射光谱仪(ICP-AES)测定了Yb^3+离子存Yb:FAP晶体中的分凝系数约为0.03。随着晶体的生长,晶体中Yb^3+离子的轴向浓度逐渐增大。研究Yb:FAP晶体在77K和300K温度下的吸收光谱发现,振动谱的变化主要是由电子-声子近共振耦合作用引起的。系统地研究了不同Yb^3+离子掺杂浓度Yb:FAP晶体的吸收光谱和荧光光谱。通过吸收光谱的测量计算了晶体的吸收截面。Yb:FAP晶体在904nm和982nm处存在Yb

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采用提拉法(CZ)生长了质量优异的Tm:YAG晶体.部分晶片在1000℃的空气气氛中退火25h.借助光学显微镜、扫描电子显微镜(SEM),结合化学腐蚀法,对Tm:YAG晶体退火前后(111)面的缺陷特征进行了研究.Tm:YAG晶体(111)面的位错腐蚀坑呈三角形.在偏光显微镜下观察了退火前后Tm:YAG晶体(111)面的应力双折射.同时应用高分辨X射线衍射法测定了晶体的完整性.实验结果表明,长时间空气气氛下高温退火有效降低了晶体中总的位错密度,提高了晶体质量.

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A large and transparent Yb:FAP crystal with dimensions up to circle divide 30 mm x 85 mm has been grown by the Czochralski method. The preparation of the raw material has been investigated. X-ray power diffraction studies of Yb:FAP crystal confirm that the as-grown crystal is isostructural with the FAP crystal. The crystalline quality has been studied using X-ray rocking curve analysis. The segregation coefficient of Yb3+ in the Yb:FAP crystal has been also determined. Linear thermal expansion coefficients in [001] and [100] directions have been measured in the 30-800 degrees C temperature range. (c) 2005 Elsevier B.V. All rights reserved.

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For the first time, the effect of Na+ on crystal structure, valence state of Yb ions, spectroscopic properties of YbF3-doped CaF2 system was systematically studied. Na+ can greatly suppress the deoxidization of Yb3+ to Yb2+. Absorption and emission spectra showed codoping Na+ with different Na:Yb ratios can modulate the spectroscopy and photoluminescence properties of Yb3+ ions in CaF2 lattice in a large scope. The emission lifetime and quantum efficiency of Yb3+ in CaF2 were greatly enhanced by the codopant of Na+. The potential laser performances of the new Yb, Na-codoped CaF2 crystals were predicted. (c) 2005 Elsevier B.V. All rights reserved.

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由溶胶一凝胶/燃烧合成结合法合成了Nd:YAG(掺钕钇铝石榴石,neodymium—doped yttrium aluminium garnet)粉体,用真空烧结法制备了Nd:YAG透明陶瓷。研究了显微结构随烧结温度和保温时间的变化,并对透明陶瓷的晶界结构和成分分布进行了表征。随着烧结温度的提高和保温时间的延长,Nd:YAG陶瓷的密度增大,晶形发育完整,透过率提高。晶粒内部和晶界的化学组成基本相同。所制备的Nd:YAG透明陶瓷在激光工作波长1064nm的透过率达到75%。

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采用提拉法生长了质量优异的Yb:Ca5(PO4)2F(Yb:FAP)晶体。运用化学腐蚀,光学显微镜、扫描电子显微镜以及能量散射光谱仪观察了该晶体中的生长条纹和包裹物等宏观缺陷,以及晶体的位错腐蚀形貌、位错密度及其分布情况,同时观察了晶体中亚晶界的形态。由晶体中位错的径向变化以及生长条纹可知:晶体在生长过程中为微凸界面生长。高温下CaF2的挥发造成了在晶体生长后期熔体中组分偏离化学计量比,出现组分过冷,形成包裹物。且位错密度显著增加。Yb:FAP晶体的各向异性使得晶体在(10 10)面的位错蚀坑形状、大小以

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采用传统陶瓷烧结工艺,在无压还原气氛中低温制备了Yb^3+掺杂量高达10%(按摩尔计)的透明性良好的氧化镧钇激光陶瓷,研究了其在室温的吸收光谱、发射光谱以及荧光寿命。结果表明:掺Yb^3+氧化镧钇透明激光陶瓷具有宽的吸收和发射光谱以及长的荧光寿命。吸收峰位于902,942nm和968nm处,吸收截面分别为0.31×10^-20,0.45×10^-20cm^2和0.53×10^-20cm2:主发射峰位于1032nm和1075nm处,发射截面分别为1.05×10^-20cm^2和0.87×10^-20cm ^