排序方式: 共有39条查询结果,搜索用时 234 毫秒
21.
利用提拉法生长了Si4+共掺杂Yb∶YAG单晶,该晶体属于立方晶系,Oh10-Ia3d空间群。掺杂的Si4+没有改变YAG的晶体结构,但是影响了发光离子的价态。吸收光谱表明Si4+的引入使得Yb2+含量增多,这是由于Si4+引入了过量的电荷,为满足电价平衡,Yb3+转换为Yb2+。Yb2+的出现降低了Yb∶YAG的发光强度。稳态X射线激发发射光谱结果表明Si4+共掺杂Yb∶YAG晶体的发光强度是Yb∶YAG的63%,γ射线激发下的光产额降至原来的40%。此外,由于原料中含有多种Yb的同位素,Yb∶YAG除了可以被X射线、γ射线激发出荧光外,还可以与中子发生核反应产生带电粒子,进而引起次级反应产生荧光。荧光的产生仍然由Yb3+决定,因此,Si4+掺入也降低了中子探测灵敏度。 相似文献
22.
A novel single-cavity narrowband Fabry-Perot (FP) polarizing filter at normal incidence, constructed from a sandwich structure with sculptured anisotropic space layer and symmetric isotropic HR mirrors, is designed and prepared. The optical performances of transmittance, phase shift, central wavelength, and bandwidth for two polarized states are analyzed with the characteristic matrix. The numerical studies accord reasonably well with the experimental results. It is demonstrated that the polarization state of the electromagnetic wave and phase shift can be modulated by employing an anisotropic space layer in the polarizing beam splitter system. The birefringence of the anisotropic space layer provides a sophisticated phase modulation by varying the incidence angles over a broad range to have a wide-angle phase shift. 相似文献
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在4H-SiC基底上设计并制备了Al2O3SiO2紫外双层减反射膜,通过扫描电镜(SEM)和实测反射率谱来验证理论设计的正确性.利用编程计算得到Al2O2和SiO2的最优物理膜厚分别为42.0 nm和96.1 nm以及参考波长λ=280 nm处最小反射率为0.09%.由误差分析可知,实际镀膜时保持双层膜厚度之和与理论值一致有利于降低膜系反射率.实验中应当准确控制SiO2折射率并使Al2O3折射率接近1.715.用电子束蒸发法在4H-SiC基底上淀积Al2O3SiO2双层膜,厚度分别为42 nm和96 nm.SEM截面图表明淀积的薄膜和基底间具有较强的附着力.实测反射率极小值为0.33%,对应λ=276 nm,与理论结果吻合较好.与传统SiO2单层膜相比,Al2O3SiO2双层膜具有反射率小,波长选择性好等优点,从而论证了其在4H-SiC基紫外光电器件减反射膜上具有较好的应用前景. 相似文献
24.
用直流溅射法在室温K9玻璃基底上制备了8.2nm—107.2nm范围内不同厚度的Ag薄膜,并用X射线衍射及计算机辅助优化程序对薄膜的微结构和光学常数进行了测试分析. 结构分析表明:制备的Ag薄膜均呈多晶状态,晶体结构均呈面心立方;随着膜厚的增加,薄膜的平均晶粒尺寸逐渐增大,晶面间距逐渐减小. 计算机辅助优化编程计算的薄膜光学常数分析表明:在波长550nm处,当膜厚小于17.5nm时,随着膜厚的增加,折射率n快速减小,消光系数k则快速增大;当膜厚大于17.5nm时,n和k逐渐趋于稳定.
关键词:
直流溅射镀膜
银膜
微结构
光学常数 相似文献
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设计了中心波长800 nm带宽约500 nm的啁啾镜对, 在550–1050 nm波长范围内提供约-60 fs2群延迟色散(group delay dispersion, GDD), 通过啁啾镜对的形式使GDD振荡波纹由单个啁啾镜的±100 fs2减小到±20 fs2. 采用双射频离子束溅射方法进行制备, 用白光干涉仪进行色散性能测试, 从测试结果可以看出, 制备的啁啾镜的反射率、GDD性能和设计值符合得比较好. 制备出的550–1050 nm超宽带啁啾镜对在钛宝石激光器腔外进行色散补偿, 原输入脉冲由24–27 fs压缩到12 fs, 这是国产超宽带啁啾镜对的首次应用.
关键词:
超快激光
啁啾镜对
群延迟色散
色散补偿 相似文献
28.
Phase shift of polarized light through sculptured thin films: Experimental measurements and theoretical study 下载免费PDF全文
A slanted columnar TiO2 sculptured anisotropic thin film (ATF) is prepared via the glancing angle deposition technique and used as the phase retardation plate. The tilted nanocolumn microstructures of thin film induce the optical anisotropy. With the biaxial birefringent model, the optical constants dispersion equations of TiO2 ATF are derived by fitting the transmittance spectra for s-and p-polarized waves measured at normal and oblique incidence within 400 nm–1200 nm. The phase shift of polarized light after reflection and/or transmission through the TiO2 ATF is analyzed with the characteristic matrix employing the extracted structure parameters. The theoretical studies reasonably well accord with the experimental results measured with spectroscopic ellipsometry. In addition, the dependences of the phase shift on the coating physical thickness and oblique incidence angle are also discussed. Birefringence of the biaxial ATF provides a sophisticated phase modulation by varying incidence angles over a broad range to have a wide-angle phase shift. 相似文献
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A novel single-cavity narrowband Fabry–Pe′rot(FP) polarizing filter at normal incidence,constructed from a sandwich structure with sculptured anisotropic space layer and symmetric isotropic HR mirrors,is designed and prepared.The optical performances of transmittance,phase shift,central wavelength,and bandwidth for two polarized states are analyzed with the characteristic matrix.The numerical studies accord reasonably well with the experimental results.It is demonstrated that the polarization state of the electromagnetic wave and phase shift can be modulated by employing an anisotropic space layer in the polarizing beam splitter system.The birefringence of the anisotropic space layer provides a sophisticated phase modulation by varying the incidence angles over a broad range to have a wide-angle phase shift. 相似文献
30.
通过Sn助熔剂法在高温下合成一种Zintl相化合物α-BaZn2P2,通过X射线单晶衍射确定其晶体结构与α-BaCu2S2同构,属于Pnma空间群。α-BaZn2P2的晶格参数为:a=0.976 78(5) nm,b=0.413 34(2) nm,c=1.060 55(5) nm。与高温相β-BaZn2P2的层状结构不同,低温相α-BaZn2P2具有三维网格结构。其中ZnP4四面体通过共边和共顶2种方式连接形成阴离子框架,Ba2+作为阳离子填隙其中。基于密度泛函理论计算了该化合物的能带结构和态密度,结果表明该化合物是窄带隙半导体(Eg=0.4 eV)。另外,DSC和变温XRD结果表明高温下α-BaZn2P2分解为Ba4P5,ZnP4等二元相。 相似文献