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中性原子的激光导引及其应用 总被引:1,自引:0,他引:1
文章综述了采用中空光纤中红失谐高斯模式,红失谐高斯激光束,中空光纤中蓝失谐消逝波和蓝失谐暗中空光束实现中性原子激光导引的原理,方法和实验及其最新进展,并简单介绍了激光导引原子技术在原子光学领域中的应用。 相似文献
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利用全量子理论和数值计算方法,研究隧穿量子点分子模型与光场相互作用的量子信息保真度,通过计算机模拟出量子点分子、光场和系统的保真度随时间的演化图像,分析了压缩系数和失谐量对量子信息保真度的影响.结果表明:改变初始光场的压缩系数和失谐量能调节相互作用系统的量子信息保真度. 相似文献
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提出了一种采用蓝失谐局域中空光束实现中性原子冷却与囚禁的新方法,并采用Monte-Carlo模拟方法研究了局域中空光束中原子强度梯度冷却(即Sisyphus冷却)的 动力学过程. 研究发现一个温度约为5μK和密度为10^12—10^13cm^3的超冷原子样品可以在我们的单束局域中空光束势阱中获得,而且这一原子密度可通过改变聚焦系统的相对孔径来加以调控. 因此,这一蓝失谐的局域中空光束还可用于实现全光型玻色-爱因斯坦凝聚.
关键词:
局域中空光束
原子囚禁
强度梯度冷却 相似文献
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压缩相干态光场与Λ型三能级原子相互作用的纠缠特性 总被引:1,自引:1,他引:0
利用量子熵理论,研究了压缩相干态光场与Λ型三能级原子的量子纠缠随时间的演化特性.结果表明:光场与原子纠缠度依赖于初态原子能级叠加系数、光场压缩参量、相干态振幅参量及失谐量与耦合系数之比.当光场压缩参量增大时,光场与原子的最大纠缠度增大;若场失谐量与耦合系数之比增大,光场与原子纠缠则呈现周期性演化,系统呈现接近退纠缠;若场失谐量与耦合系数之比增大,光场与原子纠缠呈现周期性,场失谐量与耦合系数的比值足够大时,在一定时刻系统可处于稳定的最大纠缠态,且系统演化呈现周期性. 相似文献
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提出了一种采用单模光纤、环形二元相位板和微透镜组成的光束整形系统产生亚微米局域空心光束的方案. 根据瑞利-索莫菲衍射积分公式, 数值计算了微透镜焦平面附近的场分布, 详细研究了空心光束的暗斑尺寸与单模光纤模场半径和微透镜焦距的关系. 数值计算结果表明: 在微透镜焦平面附近光场分布近似对称, 在焦点处场强近似为零, 周围场强逐渐增大, 形成半径约为0.4 μm的三维封闭的球形空心光场区域, 即亚微米局域空心光束. 当局域空心光束为蓝失谐时, 光场中的原子将被囚禁在光场最弱处. 若加上抽运光, 原子将受到蓝失谐局域空心光束与抽运光共同激发的强度梯度Sisyphus冷却. 本文利用该方案产生的亚微米局域空心光束构建单原子的囚禁与冷却器件, 并以单个87Rb原子为例, 利用Mont-Carlo方法研究亚微米局域空心光束中单原子囚禁与强度梯度冷却的动力学过程, 结果表明利用该器件可以获得温度在5.8 μK量级的超冷单原子. 相似文献
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采用量子模型对近共振激光驻波原子透镜会聚Cr原子束、形成纳米量级光栅结构的物理过程进行数值模拟。为提高原子透镜的成像质量,对各种像差,如衍射像差、球差、色差、及原子束发散角、原子磁支能级、原子同位素等因素引起的像差进行了理论分析。模拟结果表明,相比粒子光学模型,量子模型能更加精确地描述原子会聚结果,且能解释原子在驻波光场中的衍射现象。在各种像差中,原子束发散角是最主要的因素,其影响大于衍射像差、球差、色差。原子的磁支能级、同位素等因素对像差影响很小,可以忽略不计。激光冷却准直原子束的方法可以减小束发散角引起的像差,压缩原子速度Vz分布范围的方法可以减小色差。 相似文献
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We present a generalized two-state theory to investigate the quantum dynamics and statistics of an atom laser with nonlinear couplings. The rotating wave approximate Hamiltonian of the system is proved to be analytically solvable. The fraction of output atoms is then showed to exhibit an interesting collapse and revival phenomenon with respect to the evolution time, a sign of nonlinear couplings. Several nonclassical effects, such as sub-Poissonian distribution, quadrature squeezing effects, second-order cross-correlation and accompanied violation of Cauchy-Schwartz inequality are also revealed for the output matter wave. The initial global phase of the trapped condensate, in weak nonlinear coupling limits, is found to exert an interesting impact on the quantum statistical properties of the propagating atom laser beam. 相似文献
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We present a generalized two-state theory to investigate the quantum dynamics and statistics of an atom laser with nonlinear couplings. The rotating wave approximate Hamiltonian of the system is proved to be analytically solvable. The fraction
of output atoms is then showed to exhibit an interesting collapse and revival phenomenon with respect to the evolution time, a sign of nonlinear couplings. Several nonclassical effects, such as sub-Poissonian distribution, quadrature squeezing effects, second-order cross-correlation and accompanied violation of
Cauchy-Schwartz inequality are also revealed for the output matter wave. The
initial global phase of the trapped condensate, in weak nonlinear coupling
limits, is found to exert an interesting impact on the quantum statistical properties of the propagating atom laser beam. 相似文献
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针对现有的冷原子实验用的多数保偏光纤输入型扩束准直器不能对输入激光束的偏振进行精确调节的缺陷,提出了一种全长度为135mm,输出圆形光斑有效直径为20mm的紧凑型偏振可调激光扩束准直器.该扩束准直器中的偏振棱镜和波片偏振轴均可独立调节,能对单模保偏光纤输入光束的偏振态进行精确调节和保持.所研制的激光扩束准直器在三维磁光阱冷原子实验中制备出了满足冷原子干涉实验要求的冷原子团,冷原子团原子数为5×108,温度约为10μK,并获得了最大上抛高度为1.156m的原子喷泉飞行时间信号. 相似文献
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A cold atom source is important for quantum metrology and precision measurement. To reduce the quantum projection noise limit in optical lattice clock, one can increase the number of cold atoms and reduce the dead time by enhancing the loading rate. In this work, we realize an enhanced cold mercury atom source based on a two-dimensional (2D) magneto-optical trap (MOT). The vacuum system is composed of two titanium chambers connected with a differential pumping tube. Two stable cooling laser systems are adopted for the 2D-MOT and the three-dimensional (3D)-MOT, respectively. Using an optimized 2D-MOT and push beam, about 1.3×106 atoms, which are almost an order of magnitude higher than using a pure 3D-MOT, are loaded into the 3D-MOT for 202Hg atoms. This enhanced cold mercury atom source is helpful in increasing the frequency stability of a neutral mercury lattice clock. 相似文献
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基于半经典理论,分析了中性钠原子在激光驻波场中的受力特征,以此为基础分别对不同纵向运动速度和横向运动速度条件下中性钠原子的运动轨迹进行了仿真运算,得到了不同速度条件下中性钠原子的运动轨迹特征,基于累计算法进一步对不同速度条件下中性钠原子的沉积特性进行了仿真,当钠原子的纵向运动速度符合最可及速度(740 m/s)时,纳米沉积条纹的半高宽为2.78 nm,条纹对比度为38.5 ∶1,当纵向运动速度偏离最可及速度(350 m/s)时,纳米沉积条纹的半高宽为29.1 nm,其对比度下降为15 ∶1.而当中性钠原子
关键词:
原子光刻
激光驻波场
条纹半高宽
条纹对比度 相似文献
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Long, narrow all-light atom guide 总被引:5,自引:0,他引:5
A 1-mm-diameter all-light atom guide capable of transporting ultracold atoms tens of centimeters with high efficiency is described. We made the atom tunnel, a dark hollow beam that is blue detuned from resonance, by passing a few tens of milliwatts of energy from a TEM(00) diode laser beam through an optical sequence composed of three axicons and a simple lens. We demonstrate transport of 10(8)Cs atoms approximately 20 cm with minimal heating. We show that it is possible for one to control the direction and speed of the atoms in the tunnel by varying the detuning of the tunnel beam. 相似文献