利用原子束研究光的力学效应

本文介绍了我们利用原子束研究光的力学效应的原理、方法和主要结果．我们测量了激光偏转原 子束的原子空间分布，观察了在光场作用下原子动量的扩散，验证了二能级原子共振荧光中亚泊松光子，统计分布，研究了慢原子在驻波场中的运动行为，提出了沟道原子光谱技术的新方法，并用这种方法观 察了钠原子的超精细结构．     

光的力学效应及光阱力的测量

介绍一个利用光镊技术直观地演示光的力学效应的实验。简要讨论了开设这一实验的背景和目的，给出了光镊原理、实验装置、光阱力的测量方法和实验安排。     

腔光力学研究进展

腔光力学研究光子与宏观机械振子的相互作用,目前已成为研究量子世界与经典世界之间的过渡以及研究非经典和非线性效应的重要领域。本文首先介绍该领域中的基本物理概念,包括辐射压力、光机械哈密顿量、海森堡–朗之万方程、方程的线性化等。然后综述近年来一些新奇光力学效应的发现和研究进展,包括光力诱导透明、非互易光传播、高阶边带产生、光机械纠缠等。最后提出了一些研究展望。     

球面波场下原子的力学效应及球面波磁光阱

从理论上计算了原子在球面波场中的受力情况,提出具体球面波磁光阱(MOT)的方案,计算结果表明,球面波冷却和捕陷原子的方法具有冷却原子的范围大和捕陷原子的数目多,冷却效率高等优点。并可极大地缩小装置的体积。     

利用激光微束力学效应操纵生物体的实验研究

用光线光学方法对光束作用于微粒的力学问题进行分析,着重介绍了利用激光微束力学效应对多种生活活性细胞进行操纵的实验研究。     

量子光力学

2012年7月出版的Physics Today杂志刊登了维也纳大学物理系的Markus Aspelmeyer教授、亚利桑那大学物理系与光科学学院的Pierre Meystre教授和加州理工学院应用物理系的Keith Schwab教授关于量子光力学的特写文章.摘译如下：     

光的多普勒效应实验--介绍一个自学物理实验

介绍利用一台迈克耳孙干涉仪,配上一套自制的可使反射镜缓慢移植的简易装置进行光的多普勒效应测速实验。     

应变液晶的负压光效应和反式压光效应

介绍聚合物分散液晶和应变液晶概念,给出聚合物分散液晶调光玻璃的"正压光效应"、"负压光效应"和"反式压光效应"三种效应定义.实验制备出负压光效应和反式压光效应新型应变调光玻璃样品,测试样品散射态雾度90%以上,半透明态透光率接近30%.用偏光显微术研究压光效应原理,表明对样品施加垂面按压或拉伸的应力诱导作用会引起液晶微滴中液晶分子具有某些特殊排列方式,导致样品光学性质发生显著变化.建立垂面拉伸液晶微滴模型,计算模拟所绘出的图形与偏光显微镜照片独特花样十分相似,进而合理解释了实验现象.应变液晶压光效应研究具有聚合物分散液晶基础研究意义和开发非电控调光玻璃的实际应用价值.     

FP腔中光驱动微悬臂的双稳效应的研究

研究了高灵敏度悬臂梁与光纤端面构筑的低精细度FP型光腔中光驱动的悬臂梁振动的双稳效应。通过改变输入到光腔内的激光功率,检测与之相应的悬臂梁的形变。在实验中发现悬臂梁的形变随激光功率的改变呈现非线性变化的关系,在激光功率增大到一定闽值时可以诱导产生光力双稳效应。通过改变光腔初始腔长成功实现了对产生光力双稳效应阈值的调节。     

Research on mechanical stability for third-generation light source

The mechanical stability, a key problem for the 3^rd synchrotron light source, is essential for the electron beam performance. This paper analyzes the influences of the first eigenfrequency and Q value on the mechanical stability. Then the research on the improvement of the mechanical stability for the magnet girder assemblies (MGAs) and the dipole concrete assemblies (DCAs), both of which are the main parts of the Shanghai Synchrotron Radiation Faculty (SSRF), is performed. The measurement result shows that the mechanical stability is improved obviously for the MGAs by using the auxiliary supports and for the DCAs by using polymer-modification concrete instead of common concrete. The paper can give some guidance to the mechanical design of the 3^rd generation light sources.     

天文光纤机械扰模器调制环形光场的实验研究

光纤入射光束的角度和位置的变化对光纤出射光束的远场光强分布有较大影响。通过分析光纤出射光场的光强分布,研究了斜光束的偏轴角对光纤出射光场的影响。光纤耦合理论说明光纤的宏弯曲会使光纤内部模式相互耦合,根据这一原理设计一种能使光纤宏弯曲并以此来改善光纤出射场分布的机械扰模器。在实验中,对不同偏轴角入射及处于不同扰模程度的光斑进行中值滤波、高斯拟合等处理,得到光斑的径向光强分布曲线、高斯拟合度、不同出射焦比范围的能量变化等参数,以此分析机械扰模器的扰模效果。     

光拍频法测光速实验的改进

光速的测定是物理学中一个十分重要的课题,文章介绍光拍法测光速原理,结合现有实验仪器,对原有光拍频法测光速的公式加以变换,光速测量的精度有了很大提高。     

Distortion effects in light hypernuclei

We have studied the particle-bound levels in the hypernuclei_Λ ^3,4H,_Λ ⁵He,_Λ ⁸Li and_Λ ^8,9Be in the framework of the full microscopic Resonating Group Method (RGM). In a first step we have solved the respective nuclear many-body problem within the RGM. For each hypernucleus we have then performed a static calculation, in which the nuclear degrees of freedom were kept fixed, and a dynamical calculation in which nuclear degrees of freedom were allowed to vary. The differences between these two studies allowed us to investigate nuclear distortion effects caused by the presence of theΛ-particle. We find the nuclear distortion effects to be inverse proportional to the binding of the nuclear constituents. Thus, the strongest effects are observed for_Λ ³H and for_Λ ⁹Be. Our dynamical approach does not show the strong overbinding of_Λ ³H and_Λ ⁹Be as reported in other cluster model studies. Our results for thep-shell hypernuclei agree reasonably well with those obtained in a semi-microscopic Orthogonal Condition Model (OCM) study which used the same effectiveΛN-interaction as employed in our calculation.     

液晶光阀实时图像变换实验

利用“液晶光阀变换系统”,开发和设计了“液晶光阀实时图像变换实验”。该实验内容包括：测试液晶光阀的工作曲线,确定液晶光阀的对比度,测试液晶光阀的响应时间,观察单缝的频谱,图像实时反转和微分,图像实时相减。     

一种基于机械式拼接的结构光扫描测量方法

测量大尺寸零部件一般需要较大的测量范围,而高精密扫描传感器往往视野较小。为了解决该矛盾,提出了一种基于机械式拼接的结构光扫描测量方法,通过结构光扫描仪获取局部高精点云,并利用高精十字平移台实现数据拼接。分析了测量系统的组成和测量原理,提出了一种基于加权非线性优化的外参标定方法,求解出结构光扫描仪和十字平移台之间非实物坐标系的变换关系。在实验中验证了系统在300 mm的测量范围内球心距的均方根误差（root-mean-square error,RMSE）优于45 μm;同时对实物进行了测量,检验了测量系统的实用性。     

Quantum mechanical single-gold-nanocluster electroluminescent light source at room temperature

Electrically contacted gold-nanocluster arrays formed within electromigration-induced break junctions exhibit bright, field-dependent electroluminescence in the near infrared (650-800 nm). Intensity autocorrelation of spatially isolated individual nanocluster emission driven at high electrical frequency (f(ac)= approximately 200 MHz) reveals antibunched electroluminescence at room temperature. These results demonstrate the single quantum nature of several-atom gold molecules and suggest their use as room-temperature electrically driven single-photon sources.     

Generating EPR-entangled mechanical state via feeding finite-bandwidth squeezed light

Einstein–Podolski–Rosen(EPR) entanglement state is achievable by combining two single-mode position and momentum squeezed states at a 50:50 beam-splitter(BS). We investigate the generation of the EPR entangled state of two vibrating membranes in a ring resonator, where clockwise(CW) and counter-clockwise(CCW) travelling-wave modes are driven by lasers and finite-bandwidth squeezed lights. Since the optomechanical coupling depends on the location of the membranes, CW and CCW can couple to the symmetric and antisymmetric combination of mechanical modes for a suitable arrangement, which corresponds to a 50:50 BS mixing. Moreover, by employing the red-detuned driving laser and tuning the central frequency of squeezing field blue detuned from the driving laser with a mechanical frequency, the squeezing property of squeezed light can be perfectly transferred to the mechanical motion in the weak coupling regime. Thus, the BS mixing modes can be position and momentum squeezed by feeding the appropriate squeezed lights respectively, and the EPR entangled mechanical state is obtained. Moreover, cavity-induced mechanical cooling can further suppress the influence of thermal noise on the entangled state.     

A one-dimensional microscopic quantum mechanical theory of light enhanced desorption

A one-dimensional microscopic quantum mechanical model is used to inquire whether it is possible to enhance the desorption rate by employing a laser to induce vibrational excitation of the chemisorptive bond. For model parameters simulating CO/Cu it is found that the required laser intensity is very large, roughly 10⁴ times that of a conventional high power CO₂ laser (whose intensity we take to be $\text{5 × 10}{}^{10}\text{W}\text{cm}{}^2$). We suggest that surface roughness can be used to enhance substantially the effect of the laser and possibly to enable the observation of laser enhanced desorption.