操作腔外原子可控制腔内原子的压缩特性

原子偶极压缩效应的研究一直是量子光学领域中的一个十分活跃的课题,而且这些研究中多限于初始处于单原子的单态或叠加态、双原子的直积态或相干态与光场的相互作用.近年来,原子的纠缠态引起了人们极大的研究兴趣.因为纠缠态不仅证明了量子力学的非局域性,而且被广泛应用于量子计算、量子密码术、量子隐形传态等方面.最近, Yang等人研究了初始处于EPR态的两个两能级原子,其中一个注入真空态腔中,然后通过对腔外原子的操作可以控制腔内原子的发射性质.Lin等人考虑了初始处于GHZ态的三个两能级原子,让其中两个原子分别注入两个处于真空态的共振腔中.在本文中,我们分别考虑原子初始处于EPR态或GHZ态,将其中一个或两个原子同时注入一个处于相干态的光腔中,在共振条件下通过操纵腔外原子来研究腔内原子的偶极压缩效应.结果表明:对腔外原子执行一次旋转操纵和测量,可以改变腔内原子存在的偶极压缩特性.这方面的研究工作对量子态的制备和腔场的辐射控制具有一定的实际意义.     

Microwave coherent manipulation of cold atoms in optically induced fictitious magnetic traps on an atom chip

We propose a novel on-chip platform for controlling and manipulating cold atoms precisely and coherently. The scheme is achieved by producing optically induced fictitious magnetic traps(OFMTs) with 790 nm(for ~(87)Rb) circularly polarized laser beams and state-dependent potentials simultaneously for two internal atomic states with microwave coplanar waveguides. We carry out numerical calculations and simulations for controlled collisional interactions between OFMTs and addressable single atoms' manipulation on our designed hybrid atom chips. The results show that our proposed platform is feasible and flexible, which has wide applications including collisional dynamics investigation, entanglement generation,and scalable quantum gates implementation.     

Ba原子6s6p1P1←6s6s1S0跃迁的光腔衰荡光谱

建立了一套光腔衰荡原子束吸收光谱测量装置,并对Ba原子的6s6p¹P₁←6s6s¹S₀吸收谱线用光腔衰荡光谱方法进行了测量,得到了Ba原子在553.548nm不同温度下的吸收谱线线型.实验结果表明,该装置测量吸收灵敏度达到6×10^-7. 关键词： 光腔衰荡 吸收光谱 Ba原子     

Rb原子磁光阱中囚禁原子数目与实验参数的依赖关系

研究表明，Rb原子磁光阱中所囚禁的原子数目对囚禁光的光强和失谐量，回泵光的强度以及磁场梯度有很大的依赖关系.用二能级系统模型对囚禁原子数目随囚禁光的光强和失谐量的变化关系进行了预估，理论预测的结果与实验结果定性符合.实验结果也展示了囚禁原子数目随回泵光的强度和磁场梯度的变化关系，要定量解释这些实验结果则需要更复杂的理论模型.通过囚禁原子数目对实验参数依赖关系的研究，得到特定的实验参数，来获得最大数目的冷原子. 关键词： 磁光阱 冷原子     

Production of Hyperpolarized 129^Xe Gas Without Nitrogen by Optical Pumping at 133^Cs D2 Line in Flow System

We report production of hyperpolarized 129^Xe gas via spin-exchange with optically pumped Cs atoms at the D2 line, achieved at low magnetic field in a flow system and in the absence of nitrogen gas. The nuclear spin polarization of hyperpolarized 129^Xe gas is enhanced by a factor of 10000 compared to that without optical pumping under the same condition, which corresponds to polarization of about 2.66%. Due to the high spin polarization, the radiation damping of hyperpolarized 129^Xe gas has also been observed in the flow system.     

低场流动系统中超极化129Xe气体辐射阻尼的研究

辐射阻尼现象通常只有在高磁场中,利用高分辨率谱仪,才能观测到液态,像水质子这样具有大自旋浓度的信号.但是我们在低场流动系统中,利用光泵自旋交换的方法,获得高度极化的129Xe气体,从而使我们能观测到,流动系统下超极化129Xe的气态辐射阻尼信号.     

O(~3P) C_2F_4反应生成的CF_2(~3B_1)

本文报道O(~3P) C_2F_4化学发光反应生成的CF_2(~3B_1)的发射光谱和能量转移的实验研究结果,获得了一些新的振动带和Franck-Condon因子,并给出了CF_2(~3B_1)的振动态粒子数分布与C_2F_4流量的关系。     

厚透镜近似下激光驻波场中原子动力学研究

研究了在厚透镜近似下 ,原子在激光驻波场中的动力学行为 .通过直接演化一维薛定谔方程 ,发现当激光的强度较大时 ,原子束将会聚焦形成几个焦点 .如果激光的强度更大 ,驻波场中的原子将会出现一种“隧道”现象 ,此时 ,原子受一些实验参数 (如焦平面位置、激光强度等 )的影响程度将大大降低 .这种现象有利于提高原子在驻波场中聚焦沉积的效果 . The dynamics of atoms in laser standing wave (SW) in the regime of over-focused immersion-lens is studied. Through directly evolving a one-dimensional Schrdinger equation, we find that multiple focusing appears when laser intensity is larger than that required for simple focusing. If laser intensity is much higher than that for the single focusing, a "channeling" phenomenon appears, which is insensitive to the variation of some parameters, such as focal plane position and laser intensity...     

氟原子与溴代甲烷反应化学发光研究

用光子计数技术系统地探测了F(~2P)原子与溴代甲烷等(CH_3Br、CH_2Br_2和GHBr_3)反应在各种压力下的可见区(300～900 nm)化学发光,得到HF电子基态振动泛频跃迁及Br_2(B)、BrF(B)、GHF(A)、CH(A)等分子电子激发态跃迁的发射谱.求出HF(v=3)转动温度为480 K,计算机模拟光谱获得了Br_2(B)的振动布居.对比F与氯代甲烷反应的机理分析表明,初级反应主要是F提取H形成HF,多级反应产生了电子激发态的产物分子。     

Scaled-energy spectroscopy of a ｜M｜= 1 Rydberg barium atom in an electric field

We observe strong energy-dependent quantum defects in the scaled-energy Stark spectra for |M| = 1 Rydberg states of barium atoms at three scaled energies: ε = 2.000,ε = 2.500 and ε = 3.000.In an attempt to explain the observations,theoretical calculations of closed orbit theory based on a model potential including core effect are performed for non-hydrogenic atoms.While such a potential has been uniformly successful for alkali atoms with a single valence electron,it fails to match experimental results for barium atoms in the 6snp Rydberg states with two valence electrons.Our study points out that this discrepancy is due to the strong perturbation from the 5d8p state,which voids the simple approximation for constant quantum defects of principle quantum number n.