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排序方式: 共有26条查询结果,搜索用时 31 毫秒
1.
建立非平行光入射多层膜的模型,给出了在圆形光束锥角入射时的薄膜特性表达式,对三类典型光学薄膜即多腔滤光片、非偏振分光薄膜和非偏振截止滤光薄膜的特性进行了数值实验。研究结果表明:随着光束入射锥角的增加,多腔滤光片的影响是中心波长向短波方向移动,透射率下降和通带形状退化;非偏振分光薄膜的s和p偏振透射率增加,宽带波纹度增加;非偏振截止滤光薄膜的通带透射率出现周期振荡,s偏振的通带波纹度大于p偏振,通带波纹度总体具有增加的趋势,过渡区的陡度具有变大的趋势。  相似文献
2.
By using first-principles simulations based on time-dependent density functional theory,the chemical reaction of an HCl molecule encapsulated in C60induced by femtosecond laser pulses is observed.The H atom starts to leave the Cl atom and is reflected by the C60wall.The coherent nuclear dynamic behaviors of bond breakage and recombination of the HCl molecule occurring in both polarized parallel and perpendicular to the H–Cl bond axis are investigated.The radial oscillation is also found in the two polarization directions of the laser pulse.The relaxation time of the H–Cl bond lengths in transverse polarization is slow in comparison with that in longitudinal polarization.Those results are important for studying the dynamics of the chemical bond at an atomic level.  相似文献
3.
通过分析铯原子在σ~+-σ~-组态的圆偏振光照射下塞曼子能级的分布情况,构造铯原子在二维磁光阱(2D-MOT)中的受力模型,利用龙格-库塔方法求解铯原子的运动方程,实现原子束产生过程的三维模拟.得出原子束流量随小孔半径、铯原子蒸汽压、激光光强、激光失谐量、磁场梯度等的变化规律.与实验数据进行比较表明受力模型的正确性,该方法能直观模拟原子束的产生,准确揭示原子束流量随各项参数的变化规律,为实验提供理论指导.  相似文献
4.
利用脉冲激光沉积(PLD)法在玻璃基片上室温生长SnS薄膜,并在Ar气保护下分别在200,300,400,500,600℃对薄膜进行快速退火处理。利用X射线衍射(XRD)、拉曼光谱仪(Raman)、原子力显微镜(AFM)、场发射扫描电子显微镜( FE-SEM)、紫外-可见-近红外分光光度计( UV-Vis-NIR)、Keithley 4200-SCS半导体参数分析仪研究了快速退火温度对SnS薄膜的晶体结构、表面形貌以及有关光学性质和电学性能的影响。所制备的SnS薄膜样品沿(111)晶面择优取向生长,退火温度为400℃时的薄膜结晶质量最好。薄膜均具有SnS特征拉曼峰。随着退火温度的升高,薄膜厚度逐渐减小,而平均颗粒尺寸逐渐增大。不同退火温度下的SnS薄膜在可见光范围内的吸收系数均为105 cm-1量级,400℃时退火薄膜的直接带隙为1.92 eV。随着退火温度从300℃升高到500℃,电阻率由1.85×104Ω·cm下降到14.97Ω·cm。  相似文献
5.
采用离子束溅射(IBS)方法制备了HfO2和Ta2O5两种金属氧化物薄膜,通过测量薄膜的椭偏参数,使用非线性最小二乘法反演计算获得薄膜的光学常数。在拟合过程中,采用L8(27)正交表设计了8组反演计算实验,在初始选定Cauchy模型后,对HfO2薄膜拟合影响最大的为表面层模型,对Ta2O5薄膜拟合影响最大的为折射率梯度模型。确定了不同物理模型对拟合函数MSE的影响权重和拟合过程中模型选择的次序,按照确定的模型选择次序拟合,最后加入弱吸收模型反演计算两种薄膜的光学常数,反演计算的MSE相对初始MSE可下降79%和39%,表明拟合过程模型选择物理意义明确,具有广泛的应用价值。在500nm处,Ta2O5薄膜的折射率梯度大于HfO2薄膜,而HfO2薄膜消光系数大于Ta2O5薄膜。表明Hf金属与Ta金属相比容易氧化形成稳定的氧化物,HfO2薄膜的吸收要高于Ta2O5薄膜。  相似文献
6.
刘丹丹  张红 《中国物理 B》2013,(10):234-239
By using first-principles simulations based on time-dependent density functional theory, the chemical reaction of an HCl molecule encapsulated in C60 induced by femtosecond laser pulses is observed. The H atom starts to leave the Cl atom and is reflected by the C60 wall. The coherent nuclear dynamic behaviors of bond breakage and recombination of the HCl molecule occurring in both polarized parallel and perpendicular to the H-Cl bond axis are investigated. The radial oscillation is also found in the two polarization directions of the laser pulse. The relaxation time of the H-Cl bond lengths in transverse polarization is slow in comparison with that in longitudinal polarization. Those results are important for studying the dynamics of the chemical bond at an atomic level.  相似文献
7.
 为了制备满足设计要求的宽角度、宽波段减反膜,利用离子束溅射沉积技术,在时间-功率控厚的模式下,对膜层沉积速率进行了精确修正。在实验中,利用时间-功率控厚的离子束溅射沉积技术,选择HfO2和SiO2作为高低折射率组合,在超抛ZF6玻璃基底上制备了宽角度、宽带减反膜,通过对实验后的透过率光谱曲线的数值反演计算,获得膜层厚度修正系数,初步得到了沉积速率随沉积时间变化的规律。利用修正后的沉积参数制备设计的膜系,在0°~30°入射角度下,600~1 200 nm波段的平均透过率达到99%以上。  相似文献
8.
刘丹丹  张红 《中国物理 B》2011,20(9):97105-097105
We report theoretical studies on the plasmon resonances in linear Au atomic chains by using ab initio time-dependent density functional theory. The dipole responses are investigated each as a function of chain length. They converge into a single resonance in the longitudinal mode but split into two transverse modes. As the chain length increases, the longitudinal plasmon mode is redshifted in energy while the transverse modes shift in the opposite direction (blueshifts). In addition, the energy gap between the two transverse modes reduces with chain length increasing. We find that there are unique characteristics, different from those of other metallic chains. These characteristics are crucial to atomic-scale engineering of single-molecule sensing, optical spectroscopy, and so on.  相似文献
9.
The photoabsorption spectra of (SiO2)n (n = 2-5) clusters [including isomers (D3h, D2d) structures of (SiO2)3 and (C2v, D2h, D4h) structures of (SiO2)4] are calculated by using time-dependent density-function theory. The equilibrium geometries, the binding energy, the gap between the highest occupied and lowest unoccupied molecular orbitals and vertical ionization potential for corresponding structures are computed using several methods with different types of the basis functions. It is found that the polarizability functions are necessary for the basis functions when optimize the structures of silicon oxide clusters. For different geometries of various clusters and the related isomers, their spectra are very different. Meanwhile, the comparison between using local-density generalized-gradient approximations for exchange-correlation potentials shows that both the calculated spectra present the same spectral feature. We suggest that the calculated photoabsorption spectra could be taken as a tool to elucidate the isomers and dusters structure.  相似文献
10.
 制备低亚表面损伤的超光滑光学基底,是获得高损伤阈值薄膜的前提条件。针对石英材料在不同加工工序中引入亚表面损伤层的差异,首先利用共焦显微成像结合光散射的层析扫描技术,对W10和W5牌号SiC磨料研磨后的亚表面缺陷进行了检测,讨论了缺陷尺寸与散射信号强度、磨料粒径与损伤层深度间的对应关系;同时,采用化学腐蚀处理技术对抛光后样品的亚表面形貌进行了刻蚀研究,分析了化学反应生成物和亚表面缺陷对刻蚀速率的影响、不同深度下亚表面缺陷的分布特征,以及均方根粗糙度与刻蚀深度间的联系。根据各道加工工艺的不同采用了相应的亚表面检测技术,由此来确定下一道加工工序,合理的去除深度,最终获得了极低亚表面损伤的超光滑光学基底。  相似文献
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