87Rb D1线法拉第反常色散光学滤波

为了得到在高背景噪音下对弱信号光的提取,实验研究了基于⁸⁷Rb D₁线5S_1/2F=2→5P_1/2 F'=1跃迁的795 nm法拉第反常色散光学滤波器.充铷的样品池所含⁸⁷Rb的比例高于自然铷,样品池处在均匀的磁场中并且夹在两个相互正交的偏振片之间.入射的探测光通过样品池,与原子相互作用,由于法拉第旋转效应实现滤波功能.改变实验条件,透射结果随之明显变化.当温度从340 K升高到360 K,透射谱的变化情况被细致记录,并且分析了导致透射情况变化的原因.在适当的工作温度以及磁场条件下,得到线宽为约220 MHz的超窄带透射谱线,谱线透过率约为48%.⁸⁷Rb D₁线的实验结果优于⁸⁵Rb的吸收线.     

Simple and efficient magnetic transport of cold atoms using moving coils for the production of Bose–Einstein condensation

We have developed a simple magnetic transport method for the efficient loading of cold atoms into a magnetic trap. Laser-cooled ⁸⁷Rb atoms in a magneto-optical trap (MOT) are transferred to a quadrupole magnetic trap and they are then transported as far as 50 cm by moving magnetic trap coils with a low excess heating of atoms. A light induced atom desorption technique helps to reduce the collision loss during the magnetic transport. Using this method, we can load cold ⁸⁷Rb atoms into a magnetic trap in an ultra high vacuum chamber with high efficiency, and we can produce ⁸⁷Rb condensate atoms. PACS 39.25.+k; 32.80.Pj; 03.75.Pp     

Feshbach resonances in $\mathsf{^{23}}$Na- $\mathsf{^{87}}$Rb

We describe s-wave collisions between ultracold ²³Na and ⁸⁷Rb atoms in the presence of a magnetic field. For any collision input channel knowledge of the singlet and triplet intermolecular potentials [1] enables us to predict the variation in scattering lengths as a function of the magnetic field. We employ the Born-Oppenheimer approximation to predict several Feshbach resonances for ²³Na⁸⁷Rb. We also include a discussion of why these resonances are expected to be narrow as observed in the case of ⁸⁷Rb₂.Received: 6 August 2004, Published online: 23 November 2004PACS: 34.90. + q Other topics in atomic collisions - 03.75.Hh Multicomponent condensates     

Effect of magnetic field on a multi window ladder type electromagnetically induced transparency with 87Rb atoms in vapour cell

In this work, we experimentally study the effect of externally applied magnetic field on a ladder type EIT in a vapour cell consisting of ⁸⁷Rb atoms. The introduction of magnetic field causes the Zeeman splitting of the hyperfine levels of ⁸⁷Rb atoms and hence the number of available windows of transparency increases. We report the observation of nine such windows. Such multi window EIT systems are capable of storing pulses at the different frequencies, corresponding to these windows hence paving the way for realization of multi frequency quantum memories. Also, the total bandwidth of storage is 218.4 MHz which is two orders of magnitude higher than that typically obtained in single window EIT based storage systems. These systems have tremendous applications in the field of speedy transmission of data over a long distance quantum communication channel.     

Study of EIT resonances in an anti-relaxation coated Rb vapor cell

We study the sign of resonances obtained in electromagnetically induced transparency (EIT). Resonances of both kinds—bright (corresponding to enhanced absorption) and dark (corresponding to reduced absorption)—are obtained when the frequency of a probe beam is scanned. The experimental results, presented earlier, use magnetic sublevels of a hyperfine transition in the D₁ line of ⁸⁷Rb along with a magnetic field of 27 G. The atoms are contained in a vapor cell at room temperature, and with anti-relaxation coating on the walls. A quantitative theoretical model, which reproduces the experimental results quite well, is presented for the first time. The model solves the density matrix of the sublevels involved, and uses two regions—one with both the light and magnetic field, and the second without light and just a magnetic field. This ability to have both bright and dark resonances promises applications in sub- and super-luminal propagation of light.     

Orientational frequency shifts of microwave 0-0 superfine resonance in 87Rb vapor with selective optical pumping

The orientational frequency shift of the UHF radio-optical resonance in the ⁸⁷Rb vapor with a selective optical pumping by laser and lamp sources is studied experimentally and theoretically. A leading role of the tensor component of the light shift is noticed for both excitation modes, and a modulation technique of the resonance frequency orientation shift suppression is demonstrated. We show that it is necessary to ensure a constancy of the angle between the pump light direction and the external magnetic field vector when using a rubidium quantum discriminator based on moving and rotating carriers.     

40K-87Rb原子冷却的半导体激光系统

对⁴⁰K-⁸⁷Rb原子冷却的半导体激光系统提出了一种实验方案，并进行了初步实验.采用三台外腔光栅反馈半导体激光器(ECDL)、四台注入锁定从激光器和一台半导体激光放大器组成激光系统.三台ECDL通过声光调制器产生四束光，分别作为⁴⁰K和⁸⁷Rb原子的冷却光和再抽运光，四束不同频率成分的激光分别注入锁定四台从激光器，然后Rb 冷却光、K冷却光和K再抽运光再同时注入半导体激光放大器进行放大.该装置可同时产生冷却⁴⁰K和⁸⁷Rb原子的冷却光和再抽运光，结构紧凑、工作稳定. 关键词： 简并费米气体 激光器系统 外腔光栅反馈半导体激光器 半导体激光放大器     

<Superscript>87</Superscript>Rb NMR study of the magnetic structure of the quasi-two-dimensional antiferromagnet RbFe(MoO<Subscript>4</Subscript>)<Subscript>2</Subscript> on a triangular lattice

⁸⁷Rb nuclear magnetic resonance was experimentally studied in a quasi-two-dimensional Heisenberg antiferromagnet RbFe(MoO₄)₂. Dipole fields at the ⁸⁷Rb nuclei were found over a wide range of temperatures and static magnetic fields. Magnetic structures in the ordered phase were determined at various magnetic fields.     

Doppler-free spectroscopy using magnetically induced dichroism of atomic vapor: a new scheme for laser frequency locking

We demonstrate a Doppler-free spectroscopic method that we test on ⁸⁷Rb and ⁸⁵Rb vapor. By using a magnetic field to induce a dichroism on the sample, we generate a dispersive signal with low background, which allows us to lock a diode laser even on small spectroscopic features. We elaborate the advantages of this simple and easy method by comparing it to other methods. Received 15 October 2002 Published online 17 December 2002     

高密度冷原子云辐射陷获效应造成的荧光减弱现象

实验测量了磁光阱的磁场关断之后的荧光变化,观察到几十ms量级的荧光上升过程. 根据实验条件进行分析,在高密度冷原子云中辐射陷获效应造成额外的非相干抽运光场是造成磁光陷阱紧束缚状态下荧光减弱的原因. 同时还进行了简单的数值模拟,结果表明只有考虑到散射光场的频率重分布效应,计算结果方能与实验符合. 关键词： 冷原子云 辐射陷获 频率重分布     

Two field nonlinear Faraday rotation in rubidium vapor in a Doppler-free geometry

Nonlinear Faraday rotation with counter-propagating light beams was investigated in a rubidium vapor cell. Observations across all hyperfine and crossover resonances of the D₂ line of ⁸⁷Rb atoms were made. Additionally, rotation spectra as a function of pump and probe intensity, pump polarization and external magnetic field strength were studied.The investigations were performed in a regime where the pump beam power was sufficiently low relative to the probe power to avoid polarization rotation due to pump-induced anisotropy. Our results are analyzed in the context of Bennett structures and coherent optical processes.     

Possibility of the use of the magnetic field for creating a quantum filter on the <Emphasis Type="Italic">D</Emphasis><Subscript>1</Subscript><Superscript>87</Superscript>Rb line

The possibility of the use of the F = 2?F = 1 transition of the D ₁ absorption line of the ⁸⁷Rb atom for creating of a single-photon quantum filter based on coherent population trapping (CPT) has been analyzed. It has been shown that the external magnetic field is necessary for ensuring the creation of the quantum filter on boson isotopes of alkali atoms. The field strength should be enough for the manifestation of the splitting of the Zeeman CPT resonances that is much larger than their spectral widths. The splittings of the CPT resonances, which characterize the nonlinearity of the Zeeman effect, have been measured for the ⁸⁷Rb atom and the possibility of the use of this system for the quantum filter is concluded.     

Use of sub-Doppler optical resonances for measurement of weak magnetic fields by means of extremely thin rubidium vapor cell

We study experimentally and theoretically D ₁ lines of ⁸⁵Rb and ⁸⁷Rb atoms and show that using atomic-velocity-selective optical resonances which are formed in the transmission spectrum of an atomic rubidium-filled submicron cell at single pass of linearly polarized laser radiation, it is possible to measure weak magnetic fields beginning with 5 G. Having in mind the results obtained earlier with use of also submicron cell with ⁸⁷Rb (D ₁ line) and circularly polarized laser radiation, the entire range of measurable magnetic fields (both homogeneous and inhomogeneous) becomes 5–5000 G.     

Magnetic conveyor belt transport of ultracold atoms to a superconducting atomchip

We report the realization of a robust magnetic transport scheme to bring >3 × 10⁸ ultracold ⁸⁷Rb atoms into a cryostat. The sequence starts with standard laser cooling and trapping of ⁸⁷Rb atoms, transporting first horizontally and then vertically through the radiation shields into a cryostat by a series of normal- and superconducting magnetic coils. Loading the atoms in a superconducting microtrap paves the way for studying the interaction of ultracold atoms with superconducting surfaces and quantum devices requiring cryogenic temperatures.     

Nonlinear resonant polarization rotation under conditions of coherent population trapping

Nonlinear resonant optical rotation was studied over a wide range of experimental parameters at the Rb D ₁ F = 2→F′ = 1 transition in the ⁸⁷Rb vapor under conditions of coherent population trapping. The angle of rotation was found to depend nonmonotonically on the laser intensity and applied magnetic field. The effect of optical pumping out to the level F = 1 is discussed. It is demonstrated experimentally that the Faraday rotation angle increases twofold upon the compensation for pumping.     

Magnetic resonance frequency shifts upon spin-exchange collisions of alkali atoms

Magnetic resonance frequency shifts caused by spin-exchange collisions between ⁸⁷Rb and ¹³³Cs atoms are calculated, and temperature dependences of magnetic resonance frequency shifts are drawn for two hyperfine states (F = 1, 2) of ⁸⁷Rb atoms. The obtained dependences are compared with experimental data.     

Experimental demonstration of the sensitivity of an optically pumped quantum magnetometer

The sensitivity σ of an optically pumped quantum magnetometer is measured directly by comparing the output frequencies of ⁸⁵Rb and ⁸⁷Rb magnetometers integrated in a single two-isotope cell. The result σ₈₇=59.6±6 fT Hz^−1/2 agrees well with the value σ ₈₇ ^light =53.7±2 fT Hz^−1/2 obtained indirectly by measuring 87 the ratio of the resonance steepness to the shot noise of light.     

EXPERIMENTAL STUDY OF AC ZEEMAN EFFECT IN 87Rb ATOMIC FREQUENCY STANDARD

We have proved experimentally that the frequency shift formula of AC Zeeman effect presented by us is correct. In a ⁸⁷Rb atomic frequency standard we add a new microwave field which causes the frequency shift of O-O transition frequency of ⁸⁷Rb atomic ground state. This frequency shift as a function of frequency and power of the added microwave field is measured. The experimental results agree with theory.     

Analyses of transmission characteristics of Rb, Rb and Rb Faraday optical filters at 532 nm

In this paper, the transmission characteristics for Rb, ⁸⁵Rb and ⁸⁷Rb Faraday optical filters at 532 nm that can be used to detect the practical and important frequency-doubled Nd:YAG laser are analyzed and discussed. The theoretical model of an excited-state Faraday optical filter based on the hyperfine structures of atomic system in the intermediate field, what is to our knowledge, is firstly reported. This model predicts that the peak transmission is approximately 50% with an equivalent bandwidth of less than 3 GHz for filters operating on the 5P_1/2 → 10S_1/2 transition in Rb, ⁸⁵Rb and ⁸⁷Rb vapors, respectively. Moreover, the transmission property of ⁸⁷Rb atomic vapor is superior to that of Rb, ⁸⁵Rb atomic vapors, which makes it more suitable for the operation material of Faraday optical filters by comparison with natural Rb vapor.     

85Rb灯对87Rb原子的光抽运

本文对用⁸⁵Rb灯不经滤光泡直接对⁸⁷Rb吸收泡的光抽运作了观测,得到了比传统的用⁸⁷Rb灯经⁸⁵Rb滤光泡对⁸⁷Rb吸收泡进行光抽运更强的基态0—0跃迁共振讯号。并在一定温度下观察到负的共振讯号。到目前为止,还不能对这种负的共振讯号作出解释。同时还测量了共振线宽和光频移。对在⁸⁷Rb原子频标中应用的可能性作了评述。 关键词：