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1.
实验中通过互组跃迁689 nm激光抽运形成三重态最低能态原子布居,引入688 nm激光改变三重态最低能态间的原子布居,利用抽运光与探测光空间分离的方法观测碱土金属锶原子的三重态能态间跃迁(5s6s)3S1 → (5s5p)3Pj(j=0,1,2)的吸收谱线,对应三条跃迁线的激光波段为679 nm, 688 nm和707 nm.探测三重态原子跃迁谱线可以用于锶原子冷却中再抽运光707 nm和679 nm激光频率的直接锁定,相比于通常利用的腔传递技术,可以把再抽运光频率锁定在原子跃迁谱线上,有利于提高锶原子冷却中俘获原子数目的长期稳定性. 相似文献
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高强度的亚稳态惰性原子束流在原子分子物理实验研究中具有广泛的应用.使用射频电离方法和激光横向冷却技术制备了高强度的亚稳态氪原子束流,并使用数值模拟方法对横向冷却激光场中的原子径迹进行了分析.通过激光诱导荧光光谱方法测量原子束的束流特性,结果显示,横向冷却后在束流源下游230 cm处的原子束流强度达1.6atoms/(s*sr),束流强度提高了两个量级.利用这种高强度原子束流,我们成功囚禁了1.3×1010个亚稳态84Kr原子,同时冷原子装载速率达到了3.0×1011atoms/s;并利用该装置成功地实现了高亮度的亚稳态氩原子束和原子阱.
关键词:
横向冷却
原子束
原子阱
惰性气体 相似文献
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利用纳秒激光脉冲所激发的超声纵波, 非接触地测量了蓝宝石单晶沿c轴方向的弹性模量 C33随温度的变化关系. 结果表明, 在室温到1000 ℃ 的范围内, 蓝宝石的弹性模量C33随温度T的升高而减小, 两者之间近似呈如下二次关系: C33 = - 1.541× 10-5T2 - 0.021T + 498.3. 由于该方法利用激光烧蚀效应激发出了强度很大的纵波, 因此对弹性模量的测量具有较高的精度, 估算C33的测量误差不超过0.1%. 相似文献
7.
本文从理论和实验上对Cs39D态Rydberg原子在弱电场作用下的Stark效应做了详细研究. 理论上利用数值方法计算了Cs原子39D态的Stark结构;实验上,采用两步激发超冷基态原子获得超冷Rydberg原子,通过场电离的方法获得了39D态的Stark光谱,测量获得α5/22,α5/20,α3/22和α3/20相应的极化率分别为:62(7),-146(13), 73(6) 和-106(20) MHz·V-2cm2,实验结果与理论相符合. 相似文献
8.
应用群论及原子分子反应静力学方法推导了SiO2分子的电子态及其离解极限,采用B3P86方法,在6-311G**水平上,优化出SiO2基态分子稳定构型为单重态的C2V构型,其平衡核间距Re=RSi—O=0.1587 nm,∠OSiO=111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率ν(B2)=945.4cm-1,弯曲振动频率ν(A1)=273.5 cm-1和反对称伸缩振动频率ν(A1)=1362.9cm-1.在此基础上,使用多体项展式理论方法,导出了基态SiO2分子的全空间解析势能函数,该势能函数准确再现了SiO2(C2V)平衡结构. 相似文献
9.
利用新建激光溅射交叉分子束装置,结合时间切片速度成像技术开展了金属原子态-态反应动力学的相关研究. 超声金属原子束是由激光溅射金属棒产生,结合无气体溢流通道的自由扩散设计,得到了质量很好的金属原子超声束. 本文选择Al+O2反应体系来测试新建金属交叉分子束实验装置的性能. 通过(1+1) 共振多光子电离技术,以AlO(D2∑+)为中间态来探测特定转动态的产物AlO自由基. 相同波长下可以同时得到反应产物AlO(X2∑+,v=0,N和N+14)两个转动态的速度成像,分别对应着Δv=1的P(N)和R(N+14)跃迁. 在244.145 nm同时探测到P(15)和R(29)的跃迁,形成的两个环在切片成像图中可以完全区分开,这两个跃迁分别对应着反应产物AlO(v=0,N=15)和AlO(v=0,N=29)两个转动态. 对应此两个转动态的能级差为403 cm-1. 这两个反应产物转动态的区分表明了该实验装置与最近的一篇研究报道[J. Chem. Phys. 140, 214304 (2014)]相比较,具有较好的碰撞能量分辨率. 相似文献
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通过对NO与He流动混合气体放电, 产生了激发态的NO(a4Πii) 分子. 利用光外差-浓度调制吸收光谱技术测量了NO分子在12530-12850 cm-1波段内的吸收光谱, 并标识出b4Σ--a4Πi(4,0)带在该波段内的324条光谱跃迁谱线. 采用标准4Σ--4Πi哈密顿量模型, 通过非线性最小二乘法拟合其中267条谱线, 拟合残差(0.0071 cm-1) 接近实验系统测量误差(0.007 cm-1). 获得的主要分子常数与文献提供的常数符合, 并且拟合得到了精细结构分子常数. 相似文献
11.
Sven Mannervik 《Hyperfine Interactions》2000,127(1-4):237-245
Collinear ion beam laser spectroscopy has been utilized in the ion storage ring CRYRING in order to measure lifetimes of metastable
states in singly charged ions. The laser light has been used for selective probing of the population decay of individual fine
structure or hyperfine structure states. With the use of a mechanical shutter, time resolved studies could be performed with
millisecond resolution. In another experiment, the cw laser light was used to optically pump stored ions from the ground state
into a specific metastable state. With most of the stored ions in the metastable state, direct observation of the decay of
the forbidden transition from the metastable state to the ground state could be observed passively. Measurements of metastable
lifetimes in Ca+, Sr+, Xe+ and Eu+ will be discussed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
Nicolò Beverini 《Optics Communications》2009,282(13):2527-6429
We carried out theoretical investigation about velocity-selective atomic excitation on long-lived (metastable) levels of an atomic vapour in a thin cell by a monochromatic laser beam, running in the normal direction. The regime of coherent Rabi oscillations is considered on the light-induced transition from a sublevel of the ground quantum term to a metastable atomic level. On the basis of density matrix equations for the two-level system, we analysed the atomic population density of the metastable level, when the sample is irradiated by resonant monochromatic laser beam with an annular cross-section versus atomic velocities and versus the detuning, the amplitude, and the geometry of the laser beam. It is shown that, in the centre of the annular region, it can be obtained a population distribution on the metastable level as a function of the laser detuning, characterized by a sharp narrow resonance profile, whose width is reduced with respect to the thermal Doppler width roughly by the ratio between the diameter of the irradiated region and the inner thickness of the cell. We suggest high-sensitive schemes, in order to detect these sub-Doppler resonances, by probing the population of the metastable state with a second laser beam, resonant with a transition leaving from the metastable level. The case of 1S0 → 3P1 spin-forbidden transition of Ca is discussed in more detail 相似文献
13.
We report on a calculation of five lifetimes of metastable levels in Ar II, obtained with a relativistic Hartree-Fock method in which most of the intravalence correlation is represented within a configuration interaction scheme while core-valence correlation is described by a core-polarization model potential with a core-penetration corrective term. The quality of the calculation has been assessed through an experimental determination of the radiative lifetime of the metastable 3d 4F9/2 level. The experiment was performed with a laser probing technique on a stored ion beam at the CRYRING of Stockholm.Received: 16 January 2004, Published online: 30 March 2004PACS:
31.10. + z Theory of electronic structure, electronic transitions, and chemical binding - 32.70.Cs Oscillator strengths, lifetimes, transition moments 相似文献
14.
M. D. Hoogerland J. P. J. Driessen E. J. D. Vredenbregt H. J. L. Megens M. P. Schuwer H. C. W. Beijerinck K. A. H. van Leeuwen 《Applied physics. B, Lasers and optics》1996,62(4):323-327
Using a three-step transverse laser cooling scheme, a strongly diverging flow of metastable Ne(3s
3
P
2] atoms is compressed into a well-collimated, small diameter atomic beam (e.g., 1.4 mrad HWHM divergence at 3.6 mm beam diameter) with an unmodified axial velocity distribution centered at 580 m/s. The maximum increase in beam flux 1.04 m downstream of the source is a factor 1400; the maximum increase in phase space density, i.e., brightness, is a factor 160. The laser power used is only 140 mW. The scheme is extendable to a large variety of atomic species and enables the application of bright atomic beams in many areas of physics. 相似文献
15.
J. Walls R. Ashby J.J. Clarke B. Lu W.A. van Wijngaarden 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):159-162
The lithium D lines were studied using a diode laser that was frequency modulated by an electro-optic modulator, to excite an atomic beam.
The transmission of part of the laser beam through an etalon was monitored to correct for the nonlinearity of the laser scan.
The results for the 6,7Li 2 S
1/2 and 2 P
1/2 hyperfine splittings agree very well with the best existing data while those for the D1 isotope shift and 6,7Li fine structure splittings disagree significantly from data obtained by a previous laser atomic beam experiment. Our result
for the D1 isotope shift is very close to the latest value computed using Hylleraas variational theory.
Received 8 April 2002 / Received in final form 26 June 2002 Published online 21 January 2003
RID="a"
ID="a"e-mail: wvw@yorku.ca 相似文献
16.
K. Suchanek M. Suchanek A. Nikiel T. Pałasz M. Abboud A. Sinatra P.-J. Nacher G. Tastevin Z. Olejniczak T. Dohnalik 《The European physical journal. Special topics》2007,144(1):67-74
An accurate optical method to measure the nuclear
polarization of 3He atoms in the 11S ground state is
described. The absorption of a weak, probe laser beam is used to
measure the relative populations of two hyperfine sublevels of the
23S metastable state that are not addressed by the pumping
laser beam. Since a common spin temperature between the ground and
metastable states is established by metastable exchange
collisions, the nuclear polarization can be derived from these
absorption measurements. The method is highly sensitive, robust,
and can be used to monitor the dynamics of optical pumping and
relaxation processes without interfering with them. It was
successfully implemented and tested in the 0.45–2.0 T magnetic
field range at the 3He gas pressure up to 67 mbar. 相似文献
17.
M. Shimizu K. Yasutake H. Ohmi A. Takeuchi H. Kakiuchi K. Yoshii Y. Mori 《Applied physics. B, Lasers and optics》2001,72(2):227-230
For laser collimation of neutral F atoms, a resonance transition cycle between the metastable and the upper excited states
(3s4
P
5/2?3p4
D
0
7/2) can be used as a two-level closed system. We have determined the lifetime of the metastable state (3s4
P
5/2) in F atoms by measuring the decay curve of the fluorescence intensity as a function of distance from the plasma source.
Combining the measured velocity of F radicals from the Doppler shift of the fluorescence peak, we have obtained the lifetime
of the F metastable state as 3.7±0.5 μs. With this short metastable lifetime of F radicals, the simple Doppler cooling method
using spontaneous light force is not practical for laser collimation of F radicals. Use of stimulated light force may be necessary
to collimate F radical beams in a short distance.
Received: 4 July 2000 / Published online: 13 September 2000 相似文献
18.
A simple method to determine the thermal focal length of LD end-pumped solid-state laser with stable resonator is presented. The M2 factor describing the quality of the beam can be obtained by scanning a slit through the multi-mode Gaussian beam field. The waist width of the beam and the corresponding TEM00 under the same parameters of laser are then deduced through the law of multi-mode Gaussian beam propagation. Based on the standard matrix theory of stable resonator, the thermal focal length of the gain medium can be easily achieved. To show the application of this approach, the thermal focal length of an LD pumped Nd:YVO4 laser is measured and the experimental results are in agreement with the theoretical prediction. 相似文献
19.
M. Boustimi J. Baudon M. Ducloy J. Reinhardt F. Perales C. Mainos V. Bocvarski J. Robert 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(2):141-144
The transmission of metastable argon atoms through nano-slit or micro-slit gratings is studied by use of time of flight and
angular analysis. This transmission departs from the simple geometric one essentially by two ways: (i) the elastic or diagonal
part of the van der Waals (vW) interaction with the solid causes an angular narrowing of the emerging beam; (ii) the off-diagonal
vW interaction induces the exothermal fine structure transition 3
P
0↦3
P
2 (ΔE = 175 meV) leading to large scattering angles; the resulting angular distribution is very sensitive to the roughness of the
surface in the direction of the depth. An extension of these experiments to transversally coherent beams is proposed. It should
be considered as a first step towards a new type of interferometer in which the inelastic diffraction makes the gratings work
as beam splitters or mirrors.
Received 6 July 2001 and Received in final form 17 September 2001 相似文献
20.
A fast krypton ion beam with an energy of 10 keV is transferred through a mass filter and neutralized in a Rb- (or Cs-) vapour charge exchange cell. The emerging beam of metastable Kr atoms of a selected Kr isotope is collinearly irradiated with a tunable cw GaAlAs diode laser at 811 nm. The spectrum of the 1s
5–2p
9 transition covers 10 GHz and consists of one line each for the five stable isotopes of Kr with even mass number and 15 hyperfine structure lines of83Kr. The individual lines are recorded by detecting the fluorescence signal perpendicular to the beams. Photons are guided to the PM tube by diffuse reflection from a high reflectance thermoplastics light collector. Up to 20 photons per atom are emitted by cycling between the two states during the flight time of 1.2 µs through the detector. The observed absorption linewidth of 100 MHz is a combination of laser linewidth and energy uncertainty in the fast atomic beam. In order to achieve maximum isotope selectivity the beam energy has to be adjusted in such a way that the Doppler shifted lines of all isotopes form an optimum pattern for detecting the very rare isotopes81Kr and85Kr in natural environmental samples. 相似文献