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341.
Crystal growth,spectroscopic characteristics,and Judd–Ofelt analysis of Dy:Lu_2O_3 for yellow laser
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Dy:Lu_2O_3 was grown by the float-zone(Fz) method. According to the absorption spectrum, the Judd–Ofelt(JO) parameters ?_2, ?_4, and ?_6 were calculated to be 4.86 × 10~(-20) cm~2, 2.02 × 10~(-20) cm~2, and 1.76 × 10~(-20) cm~2, respectively.The emission cross-section at 574 nm corresponding to the ~4F6_(9/2)→~6H_(13/2) transition was calculated to be 0.53 × 10~(-20) cm~2.The yellow(~4F_(9/2)→~6H_(13/2) transition) to blue(~4F_(9/2)→~6H_(15/2) transition) intensity ratio ranges up to 12.9. The fluorescence lifetime of the ~4F_(9/2) energy level was measured to be 112.1 μs. These results reveal that Dy:Lu_2O_3 is a promising material for use in yellow lasers. 相似文献
342.
Measurements of argon metastable density using the tunable diode laser absorption spectroscopy in Ar and Ar/O_2
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Densities of Ar metastable states 1s_5 and 1s_3 are measured by using the tunable diode laser absorption spectroscopy(TDLAS) in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma(DF-CCP). We investigate the effects of high-frequency(HF, 60 MHz) power, low-frequency(LF, 2 MHz) power, and working pressure on the density of Ar metastable states for three different gas components(0%, 5%, and 10% oxygen mixed in argon). The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction(5% or 10%) of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases,and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules. 相似文献
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344.
Defect-Related Photoresponse and Polarization-Sensitive Photodetection of Single ZnO Nanowires
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Defect-related photoconductivity of single ZnO nanowires is investigated. The photoconductivity shows powerlaw dependence with incident green laser intensity due to the defect mechanisms including both recombination centres and traps. The device based on single ZnO nanowire shows a sensitive photoresponse to green light with significant on/off ratios. In addition, the photocurrent & highly sensitive to the polarization of the incident illumination. Therefore, the nanowire may act as a polarized photodetector. 相似文献
345.
掺铬硅酸镁晶体 ( Cr:Forsterite)锁模激光器发射的 1 .3μm激光在生物图像及非线性激光显微学上的应用前景已得到充分证明 ,因此促进了实用化掺铬硅酸镁锁模激光器的研究。最近国际上有报道 :将半导体可饱和布拉格反射镜 ( SBR)或可饱和吸收体镜 ( SESAM)应用于克尔棱镜锁模激光器 ,成功实现其自启动过程。这一技术大大推动了掺铬硅酸镁锁模激光器向全固化、小型化发展。本文报道了中国科学院上海光学精密机械研究所生长的优质 Cr:Forsterite晶体 ,运用半导体可饱和反射镜技术 ,在国内首次实现全固化自启动 1 .3μm波长自锁模激光运转… 相似文献
346.
采用垂直提拉法将单层双炔酸膜转移到云母基片上,同时将13层双炔酸膜转移到经过亲水处理的单晶硅片和石英片上,使双炔酸在紫外光照射下发生拓扑聚合制备双炔酸聚合LB膜,并对双炔酸和经紫外光照射后聚合双炔酸LB膜的结构及摩擦磨损特性进行研究.结果表明:双炔酸在可见区无吸收峰,但经紫外光照射后因双炔酸聚合后形成的共轭大π键在可见区出现了吸收峰;双炔酸LB膜均匀平整,厚度约为3.5 nm,聚合后其结构发生变化,厚度降至约1.5 nm;而聚合后双炔酸LB膜的减摩性能基本保持不变,聚合前后双炔酸LB膜的摩擦系数不随载荷而变化,符合阿芒顿定律,其抗磨特性得到明显提高;磨痕结果充分表明聚合双炔酸耐磨性能较好. 相似文献
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350.
Nd3+:d3Ga5O12晶体的室温吸收光谱和荧光光谱 总被引:1,自引:0,他引:1
用提拉法生长了掺钕的钆镓石榴石(Nd3+:GG)激光晶体.研究了室温下的吸收光谱和荧光光谱性质,分析了Nd3+:GG晶体4F3/2→4I11/2能级跃迁与1.06μm附近的荧光谱线之间的关系.吸收系数、发射系数、荧光寿命分别是4.32×10-20 cm-2,2.3×10-19cm-2, 240μs, 比较了Nd3+∶GGG 和 Nd3+∶YAG 的物理参数,实验表明:d3+∶GGG较Nd3+∶YAG有一系列的优点. 相似文献