共查询到20条相似文献,搜索用时 343 毫秒
1.
L. Zhou Z. Y. Xiong W. Yang B. Tang W. C. Peng K. Hao R. B. Li M. Liu J. Wang M. S. Zhan 《General Relativity and Gravitation》2011,43(7):1931-1942
Experimental realizations of cold 85Rb atom interferometers in Wuhan are reviewed in this paper. The application of atom interferometers in local gravity measurement
are reported. The resolutions of gravity measurement are 2.0 × 10−7g for 1 s and 4.5 × 10−9g for 1,888 s. The absolute g value was derived with a difference of 1.6 × 10−7g compared to the gravity reference value. The tidal phenomenon was observed by continuously monitoring the local gravity
over 123 h. A 10-meter atom interferometer designed for precision gravity measurement and the equivalence principle test is
under construction, the latest status is reported for the first time. 相似文献
2.
Min-kang Zhou Zhong-kun Hu Xiao-chun Duan Bu-liang Sun Jin-bo Zhao Jun Luo 《Frontiers of Physics in China》2009,4(2):170-173
Precisely determining gravity acceleration g plays an important role on both geophysics and metrology. For gravity measurements and high-precision gravitation experiments,
a cold atom gravimeter with the aimed resolution of 10.−9g/Hz1/2 (1 g=9.8 m/s2) is being built in our cave laboratory. There will be four steps for our 87Rb atom gravimeter, Magneto-Optical Trap (MOT) for cooling and trapping atoms, initial state preparation, π/2-π-π/2 Raman
laser pulse interactions with cold atoms, and the final state detection for phase measurement. About 108 atoms have been trapped
by our MOT and further cooled by moving molasses, and an atomic fountain has also been observed.
相似文献
3.
This paper reports an experiment on laser cooling of 87 Rb atoms in pulsed diffuse light,which is the key step towards a compact cold atom clock.It deduces an empirical formula to simulate the pulse cooling process based on the loading of cold atoms in cooling time and the loss in the dead time,which is in agreement with the experimental data.The formula gives a reference to select the parameters for the cold atom clock. 相似文献
4.
《Physics letters. A》2014,378(30-31):2034-2037
A novel method of angled incidence for diffuse laser cooling of 87Rb is presented to improve the distribution of cold atom density in an integrating sphere. The angled injection scheme could cool more atoms in the middle of the sphere compared to the previous normal injection scheme. The loading time of the cold atoms for the angled injection scheme is twice as that of the normal injection scheme. The SNR and the contrast of the detected signal would be improved in the angled injection scheme. 相似文献
5.
6.
等效原理是广义相对论的两个基本假设之一,也是爱因斯坦对弱等效原理的推广.目前,大量实验证明弱等效原理在一定的实验精度内是成立的.将引力与标准模型统一起来的新理论都要求弱等效原理破缺,因此更高精度的弱等效原理检验具有重要的科学意义.本文介绍了原子干涉仪的原理,回顾了利用原子干涉仪开展微观粒子弱等效原理检验实验研究的历史和现状,介绍了双组分原子干涉仪检验弱等效原理实验涉及的振动噪声抑制、拉曼光移频与相位噪声抑制、四波双衍射拉曼跃迁原子干涉、信号探测与数据处理等关键问题及研究进展,分析了高精度微观粒子弱等效原理检验研究的发展趋势,介绍了长基线原子干涉仪、空间原子干涉仪、超冷原子源以及纠缠原子源制备等方面的研究动态,展望了微观粒子弱等效原理检验研究的发展前景. 相似文献
7.
提出了采用四台阶相位光栅与微透镜阵列组合产生一种新颖的表面空心微光阱阵列的方案,研究了表面空心微光阱阵列的光强分布,计算了相应的光学囚禁势,并讨论了该微光阱阵列在原子分子光学中的潜在应用.研究表明当用1W的YAG激光照射时,在1cm2面积上可产生近104个空心光阱,每个光阱具有较小的囚禁体积和较大的有效光强及其强度梯度,对85Rb原子的光学囚禁势可达190μK.如此深的光阱足以囚禁冷原子或冷分子,并可用于实现全光型原子或分子玻色-爱因斯坦凝聚,甚至制备新颖的光学晶格等.
关键词:
空心光阱
冷原子或冷分子
光学晶格 相似文献
8.
文章首先简单介绍了冷原子操纵与控制的基本原理。然后,重点介绍了几何与波动原子光学及其器件的研究内容、潜在应用和最新进展,其中包括:原子束的反射和原子反射镜;原子束偏转(折射)、聚焦成像和原子透镜;原子衍射和原子光栅;原子干涉和原子干涉仪;原子全息学及其技术等。 相似文献
9.
《Comptes Rendus Physique》2014,15(10):875-883
Since the first atom interferometry experiments in 1991, measurements of rotation through the Sagnac effect in open-area atom interferometers have been investigated. These studies have demonstrated very high sensitivity that can compete with state-of-the-art optical Sagnac interferometers. Since the early 2000s, these developments have been motivated by possible applications in inertial guidance and geophysics. Most matter-wave interferometers that have been investigated since then are based on two-photon Raman transitions for the manipulation of atomic wave packets. Results from the two most studied configurations, a space-domain interferometer with atomic beams and a time-domain interferometer with cold atoms, are presented and compared. Finally, the latest generation of cold atom interferometers and their preliminary results are presented. 相似文献
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11.
Persistent efforts in both theory and experiment have yielded increasingly precise understanding of the helium atom. Because
of its simplicity, the helium atom has long been a testing ground for relativistic and quantum electrodynamic effects in few-body
atomic systems theoretically and experimentally. Comparison between theory and experiment of the helium spectroscopy in 1s2p3P
J
can potentially extract a very precise value of the fine structure constant á. The helium atom can also be used to explore
exotic nuclear structures. In this paper, we provide a brief review of the recent advances in precision calculations and measurements
of the helium atom.
相似文献
12.
K. Nakagawa Y. Suzuki M. Horikoshi J.B. Kim 《Applied physics. B, Lasers and optics》2005,81(6):791-794
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 相似文献
13.
M. Al-Amri M. Babiker 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,48(3):417-421
We explain why a system of cold 85Rb atoms at temperatures of the order T≈ 7.78× 10-5 K
and below, but not too low to lie in the quantum reflection regime, should be automatically repelled from
the surface of a conductor without the need of an evanescent field, as in a typical atom mirror, to counteract the van
der Waals attraction. The
repulsive potential arises naturally outside the conductor and is effective at distances from the
conductor surface of about 400 nm, intermediate between
the van der Waals and the Casimir-Polder regions of variation. We propose that such a field-free reflection capability should
be useful
as a component in cold atom traps.
It should be practically free of undesirable field
fluctuations and would be operative at distances for which surface roughness, dissipative effects and other finite conductivity
effects should be negligibly small. 相似文献
14.
We report on the efficient generation of cold rubidium atoms as a potential coherent atom source for atom lithography. We
successfully trapped and cooled 2.6 × 108 atoms in 5 s with a conventional magneto-optical trap simply by enlarging the diameter of the laser beam to 20 mm. The size
of the laser-cooled atom cloud was measured to be 10 × 7 × 7 mm3. The number of trapped atoms was approximately 10 times as large as that of previous typical results, while the loading time
of atoms remained the same. 相似文献
15.
Ling Xiao Xu-cheng Wang Ben-chang Zheng Yan-ling Meng Hua-dong Cheng Liang Liu Yu-zhu Wang 《Optik》2012,123(5):442-446
Kinetic behavior of cold 87Rb atoms in integrating sphere is presented under adiabatic release. Decay time of cold atom cloud is deduced by calculation of residual cold atom number evolution under adiabatic release and agrees well with our experimental observation. Number evolutions of residual cold atoms under different kinds of acceleration have been studied in detail. Sequence laser pulse cooling is key technique for the successive operation of cold atom clock. The process of laser pulse cooling is numerically simulated and fitted with experiments, optimized distribution of cooling and dead time to get enough cold atoms is put forward to satisfy the demand of cold atom clock. 相似文献
16.
The formation of ultracold metastable RbCs molecules is observed in a double species magneto-optical trap through photoassociation below the 85Rb(5S1/2) + 133Cs(6P3/2) dissociation limit followed by spontaneous emission. The molecules are detected by resonance enhanced two-photon ionization. Using accurate quantum chemistry calculations of the potential energy curves and transition dipole moment, we interpret the observed photoassociation process as occurring at short internuclear distance, in contrast with most previous cold atom photoassociation studies. The vibrational levels excited by photoassociation belong to the 5th 0+ or the 4th 0? electronic states correlated to the Rb(5P1/2, 3/2) + Cs(6S1/2) dissociation limit. The computed vibrational distribution of the produced molecules shows that they are stabilized in deeply bound vibrational states of the lowest triplet state. We also predict that a noticeable fraction of molecules is produced in the lowest level of the electronic ground state. 相似文献
17.
J. S. Bakos G. P. Djotyan P. N. Ignácz M. Á. Kedves M. Serényi Zs. Sörlei J. Szigeti Z. Tóth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(1):141-149
The displacement of Rb atoms in a magneto-optical trap (MOT) caused by the force of a finite time series of counter-propagating
frequency modulated light pulse pairs is measured as a function of the chirp of the pulses. The frequency modulated light
pulses induced 85Rb 52S1/2 F=3 ↔ 85Rb 52P3/2 F'=2, 3, 4 excitation and de-excitation of the atoms. The result of this excitation
de-excitation process is a force causing the acceleration and, consequently, the displacement of the maximum of the spatial
distribution of the trap atoms. The time dependence of the populations of the levels of the atom are calculated — including
also the 85Rb 52S1/2 F=2 and F'=1 states — as
the result of the interaction with the finite train of counter propagating frequency modulated light pulses by the solution
of the Bloch equations. As the result of the measurement the interval of the chirp of the frequency modulated light of given
intensity where the transitions take place, are determined. The results of the experiment and the expectation on the basis
of model calculations are in qualitative agreement. 相似文献
18.
19.
S. Nakayama 《Optics Communications》1984,50(1):19-25
Theoretical calculation of 85Rb and 133Cs D1 signals in polarization spectroscopy is presented by using the method of velocity-selective optical pumping in a four-level system. Since good agreement between theory and experiment has been found in Na D1 polarized signals, the theoretical calculation can be also applied to Rb and Cs D1 lines. Rb and Cs atoms have higher total angular momentum F in the hyperfine structures than Na atom and then the calculation is more complicated. The relative signal intensities in polarization spectroscopy are compared with those in saturation spectroscopy. 相似文献
20.
Simon Rainville Michael P. Bradley James V. Porto James K. Thompson David E. Pritchard 《Hyperfine Interactions》2001,132(1-4):177-187
We report new values for the atomic masses of the alkali 133Cs, 87Rb, 85Rb, and 23Na with uncertainties ≤ 0.2 ppb. These results, obtained using Penning trap single ion mass spectrometry, are typically two
orders of magnitude more accurate than previously measured values. Combined with values of h/m
atom from atom interferometry measurements and accurate wavelength measurements for different atoms, these values will lead to
new ppb-level determinations of the molar Planck constant N
A
h and the fine structure constant α. This route to α is based on simple physics. It can potentially achieve the several ppb
level of accuracy needed to test the QED determination of α extracted from measurements of the electron g factor. We also demonstrate an electronic cooling technique that cools our detector and ion below the 4 K ambient temperature.
This technique improves by about a factor of three our ability to measure the ion's axial motion.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献