Optical Characterization of the Structural and Electrical Properties of the n-GaP Nanolayers Grown on Conductive (001) n-GaP Substrates

Physics of the Solid State - The results of investigations of the structural and electrical properties of a homoepitaxial nanoscale (001) n-GaP layer of 70 nm in thickness grown by metalorganic...     

Dimensional Magnetoacoustic Effects in Resonant Scattering of Longitudinal Phonons by a Layered Magnetic Structure

JETP Letters - The indirect spin–spin interaction through the field of virtual phonons polarized in the plane of incidence in a magnetic layer with slip boundaries in an unbounded nonmagnetic...     

银薄膜对光学基底表面粗糙度及光散射的影响

为了研究金属银薄膜与光学基底表面粗糙度和光散射的关系,提出了通过对光学薄膜矢量散射公式积分来获得界面粗糙度完全相关模型和完全非相关模型下其表面的总反射散射的方法.理论计算了光学基底上两种模型在不同厚度银膜下的总反射散射和双向反射分布函数.结果表明,当沉积在光学基底上的银薄膜的厚度大于80 nm后,两种模型下计算的银薄膜的表面总反射散射都等于基底的总积分散射,银薄膜能较好地复现出基底的粗糙度轮廓.实验研究表明为了复现基底的粗糙度,银薄膜的最佳厚度应在80~160 nm之间.     

银薄膜对光学基底表面粗糙度及光散射的影响

为了研究金属银薄膜与光学基底表面粗糙度和光散射的关系,提出了通过对光学薄膜矢量散射公式积分来获得界面粗糙度完全相关模型和完全非相关模型下其表面的总反射散射的方法．理论计算了光学基底上两种模型在不同厚度银膜下的总反射散射和双向反射分布函数．结果表明,当沉积在光学基底上的银薄膜的厚度大于80nm后．两种模型下计算的银薄膜的表面总反射散射都等于基底的总积分散射,银薄膜能较好地复现出基底的粗糙度轮廓．实验研究表明为了复现基底的粗糙度,银薄膜的最佳厚度应在80～160nm之间．     

SiGe/Si多重超晶格的声学声子光散射谱

ＳｉＧｅ／Ｓｉ多重超晶格的声学声子光散射谱黄大鸣刘晓晗王兴军朱海军蒋最敏（复旦大学物理系和应用表面物理国家重点实验室上海２００４３３）ＬｉｇｈｔＳｃａｔｅｒｉｎｇｆｒｏｍＡｃｏｕｓｔｉｃＰｈｏｎｏｎｓｉｎＭｕｌｔｉｐｌｅＳｉＧｅ／ＳｉＳｕｐｅｒｌａｔ...     

Scattering of image-potential-state electrons by steps on Cu(001)

Scanning tunneling spectroscopy (STS) reveals a distinct asymmetry in the scattering properties of an isolated step for the n=1 image-potential state on Cu(001). The elastic scattering probability for an electron traveling downstairs is determined from the strength of density oscillations in front of a step edge and is found to be approximately two times higher than for the opposite upstairs direction. A one-dimensional scattering model is extended to the case of asymmetric transmission and reflection coefficients. The calculations using the asymmetry measured by STS explain the dispersion and the decay rate of the n=1 band on Cu(119) measured by two-photon photoemission. In particular, the asymmetry of the decay rate can be described quantitatively with a minimum of adjustable parameters. While the results can also be transferred successfully to the Cu(1115) surface, the limit of applicability is reached for Cu(117) with a step separation of 3.5 nearest-neighbor distances. PACS 73.20.At; 79.60.Bm; 68.37.Ef; 72.10.Fk     

Scattering by Cu adatoms between image-potential bands on Cu(001)

With the increasing resolution and sensitivity of photoelectron spectroscopy, the influence of defects is becoming more and more obvious. Scattering processes induced by adsorbate atoms can be studied by time- and angle-resolved two-photon photoemission. We have examined the dynamics of electrons in image-potential states on the Cu(001) surface for statistically distributed Cu adatoms and have identified different scattering mechanisms. Scattering of electrons from the second (n=2) to the bottom of the first (n=1) image-potential band is observed, which we attribute to inelastic interband scattering with electrons in the bulk. At energies above the bottom of the n=2 band, resonant interband scattering from the n=2 to the n=1 image-potential band is found. The rate for these processes can be determined by modeling the time-resolved measurements via optical Bloch equations of a four-level system. Comparison of the transition and decay rates reveals that the decay rate of the n=2 electrons is almost exclusively changed by additional resonant interband-scattering processes upon adsorption. PACS 73.20.At; 79.60.Ht; 68.49.Jk     

Scattering of electrons on the Cu(001) surface by Co adatoms

Excited electrons at surfaces can be scattered by adsorbate atoms or defects, which changes the energy or momentum. Such scattering processes can be studied by energy, time and angle-resolved two-photon photoelectron spectroscopy. In this article the influence of statistically distributed Co adatoms on a Cu(001) surface on the dynamics of electrons in image-potential states is investigated. Different scattering mechanisms, such as interband, intraband, and bulk scattering are identified and analyzed quantitatively. Cobalt adatoms cause mainly quasielastic scattering of electrons in image-potential states. Inelastic processes are due to interactions with electrons in the substrate and are not significantly increased by Co adatoms. The results are compared to previous experimental and theoretical work on Cu adatoms. PACS 73.20.At; 68.49.Jk; 79.60.Ht     

(非弹性)光散射概念

(非弹性)光散射现象的发现、研究和应用已有八十余年的历史,所涉及的过程,特征量,及由此关系到的物理概念、各种图像特别的繁多;想要统一、规范它们似乎难以达到。但对已成熟的,如:光散射(包括非弹性、弹性);选择定则;虚态;散射截面;相干性;‘和’、‘差’频;波数、波矢、偏振和模式等概念还是可以给出完好的解说和认识的。该文给出了上述概念的物理内容,尽可能的给出相应的图像,以便获得明白的结论。     

激光相干层析成像的光散射模拟计算

利用低相干光作为光源的光学相干层析技术是一种新型成像技术。本文利用蒙特－卡罗（Ｍｏｎｔｅ－Ｃａｒｌｏ）模拟计算方法研究了该技术在不同的散射条件下,相干调制信号随散射系数的变化关系,得出了单次散射和多次散射的差别以及它对成像质量的影响,并进一步讨论了利用单次散射和多次散射信号,提高光学相干层析术图像清晰度和信号强度的方法。还研究了光束半径大小对成像分辨率的影响及变化过程,得出了对实验有指导意义的结果     

不同涂层对微粗糙基底的极化光散射影响

为了研究涂层与基底间的极化光散射,应用一阶矢量衍射理论推导出基底极化双向反射分布函数(PBRDF)。将理论分析结果与实验数据比较并数值模拟分析了在相关和非相关模型下,SiO2和TiO2涂层厚度对PBRDF的影响。考察了不同折射率对基底PBRDF的影响。结果表明随着SiO2涂层厚度的增加,相关和非相关模型下的PBRDF逐渐靠近同时逐渐和裸基底重合,即能逐渐复现基底的粗糙度轮廓;随着TiO2涂层厚度的增加,PBRDF逐渐变大,即TiO2涂层对基底有较好的平滑作用。折射率的实部和虚部对PBRDF的影响相反。因此通过对不同涂层PBRDF进行测量和计算可以反演出基底的光学信息。     

基片温度对PLD制备ZnO薄膜光学常数的影响

光谱椭偏仪被用来研究用脉冲激光沉积方法在Si(100)基片上,温度分别为400,500,600,700 ℃制备的ZnO薄膜的特性。利用三层Cauchy散射模型拟合椭偏参数,计算了每个温度下制备的ZnO薄膜在400~800 nm波长范围内的折射率(n)和消光系数(k)。发现基片温度对光学常数有很大的影响。通过分析XRD表征的晶体结构和 AFM表征的薄膜表面形貌,发现折射率的变化归因于薄膜堆积密度的变化。为了获得具有较好的光学和薄膜质量的ZnO薄膜,相比与其他沉积温度600 ℃或许是最佳的沉积温度。     

散射光场中的光学涡旋

散射光场中的光学涡旋叶茂，王鹏业，戴建华，张洪钧（四川大学物理系成都６１００６４）（中国科学院物理研究所北京１０００８０）ＯｐｔｉｃａｌＶｏｒｔｉｃｅｓｉｎＡＴｈｅｒｍａｌＲａｙｌｅｉｇｈＳｃａｔｔｅｒｉｎｇＬｉｇｈｔＦｉｅｌｄ￥ＭａｏＹｅ；ｐｅｎｇ...     

Opto-Mechanical Effects in Superradiant Light Scattering by Bose-Einstein Condensate in an Optical Cavity

We investigate the effects of a movable mirror (cantilever) of an optical cavity on the superradiant light scattering from a Bose-Einstein condensate (BEC) in an optical lattice. We show that the mirror motion has a dynamic dispersive effect on the cavity-pump detuning. Varying the intensity of the pump beam, one can switch between the pure superradiant regime and the Bragg scattering regime. The mechanical frequency of the mirror strongly influences the time interval between two Bragg peaks. We find that when the system is in the resolved side band regime for mirror cooling, the superradiant scattering is enhanced due to coherent energy transfer from the mechanical mirror mode to the cavity field mode.     

Opto-Mechanical Effects in Superradiant Light Scattering by Bose-Einstein Condensate in an Optical Cavity

We investigate the effects of a movable mirror (cantilever) of an optical cavity on the superradiant light scattering from a Bose-Einstein condensate (BEC) in an optical lattice. We show that the mirror motion has a dynamic dispersive effect on the cavity-pump detuning. Varying the intensity of the pump beam, one can switch between the pure superradiant regime and the Bragg scattering regime. The mechanical frequency of the mirror strongly influences the time interval between two Bragg peaks. We find that when the system is in the resolved side band regime for mirror cooling, the superradiant scattering is enhanced due to coherent energy transfer from the mechanical mirror mode to the cavity field mode.