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1.
Precise measurement of the line width of the photoassociation spectra of ultracold molecules by using a frequency shifter 下载免费PDF全文
We propose a technique to precisely measure the line width of the photoassociation spectra of the excited cesium molecule by using a frequency shifter to generate two laser beams with a precise frequency difference. A series of photoassociation (PA) spectra are recorded with two laser beam induced molecular lines, whose peak separation serves as an accurate frequency ruler to measure the line width of the PA spectra. The full width half maximum line width was studied as a function of PA laser intensity. The extrapolated value at zero laser intensity is (34.84 ± 0.22) MHz. By analyzing other broadening mechanisms, a value of (32.02 ± 0.70) MHz was deduced. It is shown that this scheme is inexpensive, simple, robust, and is promising for applications in a variety of other atomic species. 相似文献
2.
Precise measurement of the line width of the photoassociation spectra of ultracold molecules by a frequency shifter 下载免费PDF全文
We propose a technique to precisely measure the line width of the photoassociation spectra of the excited cesium molecule by using a frequency shifter to generate two laser beams with a precise frequency difference. A series of photoassociation spectra are recorded with two laser beams induced molecular lines, whose peak separation serves as an accurate frequency ruler to measure the line width of the photoassociation (PA) spectra. The full width half maximum line width was studied as a function of PA laser intensity. The extrapolated value at zero laser intensity is (34.84 ± 0.22) MHz. By analyzing other broadening mechanisms, a value of (32.02 ± 0.70) MHz was deduced. It is shown that this scheme is inexpensive, simple, robust, and is promising for applications in a variety of other atomic species. 相似文献
3.
A. Godone F. Levi S. Micalizio J. Vanier 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):5-13
An analysis of the phenomenon of coherent population trapping as observed by means of the dark state in the case of optically
thick vapors in alkali metal atoms is presented. Very different behaviors are predicted for the observation of the dark state
in the fluorescence and transmission spectra of the same atomic sample when the optical length is not negligible. Among other
effects, the dark line observed in the fluorescence signal may look inverted appearing as a bright line, while in the transmission
signal a narrowing of the line width resonance line is observed for an increase of the atomic density. In the pure three-level
scheme a subnatural width is predicted. These effects, related to the electromagnetically induced transparency phenomenon,
are readily observed in experiments, which are found to be in excellent agreement with the theory developed.
Received 28 March 2001 and Received in final form 3 October 2001 相似文献
4.
W. Hartig W. Rasmussen R. Schieder H. Walther 《Zeitschrift für Physik A Hadrons and Nuclei》1976,278(3):205-210
The frequency distribution of the fluorescent light induced by monochromatic dye laser radiation was investigated. To exclude the influence of the Doppler width a strongly collimated atomic beam was used. The spectrum was measured by means of a piezoelectrically tunable spherical Fabry Perot. The interaction region between the laser light and the atomic beam was placed into the center of the interferometer. Thus the observed fluorescence spectrum was considerably more intense than in the case where the interferometer is used separately from the beam. The fluorescence spectrum was observed for different directions of polarization of the incident laser beam. In the case of weak excitation the spectrum consists of a sharp component essentially due to elastically scattered light. At high intensities a structure of three components is observed which is in agreement with theoretical predictions when circularly polarized light is used for excitation. 相似文献
5.
W. Hartig W. Rasmussen R. Schieder H. Walther 《Zeitschrift für Physik A Hadrons and Nuclei》1976,71(6):205-210
The frequency distribution of the fluorescent light induced by monochromatic dye laser radiation was investigated. To exclude the influence of the Doppler width a strongly collimated atomic beam was used. The spectrum was measured by means of a piezoelectrically tunable spherical Fabry Perot. The interaction region between the laser light and the atomic beam was placed into the center of the interferometer. Thus the observed fluorescence spectrum was considerably more intense than in the case where the interferometer is used separately from the beam. The fluorescence spectrum was observed for different directions of polarization of the incident laser beam. In the case of weak excitation the spectrum consists of a sharp component essentially due to elastically scattered light. At high intensities a structure of three components is observed which is in agreement with theoretical predictions when circularly polarized light is used for excitation. 相似文献
6.
Implementation of a double-scanning technique for studies
of the Hanle effect in rubidium vapor 总被引:1,自引:0,他引:1
A. Atvars M. Auzinsh E. A. Gazazyan A. V. Papoyan S. V. Shmavonyan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):411-417
We have studied the resonance fluorescence of a
room-temperature rubidium vapor exited to the atomic 5P3/2
state (D2 line) by powerful single-frequency cw laser radiation
(1.25 W/cm2) in the presence of a magnetic field. In these
studies, the slow, linear scanning of the laser frequency across the
hyperfine transitions of the D2 line is combined with a fast
linear scanning of the applied magnetic field, which allows us to
record frequency-dependent Hanle resonances from all the groups of
hyperfine transitions including V- and Λ-type systems.
Rate equations were used to simulate fluorescence signals for
85Rb due to circularly polarized exciting laser radiation with
different mean frequency values and laser intensity values. The
simulation show a dependence of the fluorescence on the magnetic
field. The Doppler effect was taken into account by averaging the
calculated signals over different velocity groups. Theoretical
calculations give a width of the signal peak in good agreement with
experiment. 相似文献
7.
四能级原子相干系统的探讨 总被引:1,自引:1,他引:0
对N型四能级原子与光场相互作用的原子相干效应进行了理论计算,讨论了能级衰减率、激光线宽以及基态间的驰豫对原子相干效应的影响。原子第四能级的衰减率、激光线宽以及基态间驰豫增大,原子相干性将会减弱。 相似文献
8.
David J. Butcher 《应用光谱学评论》2013,48(6):543-562
Abstract Lasers have advantages compared to conventional light sources, which include high power, a monochromatic emission profile, stability, and rapid tuning across an atomic line. These advantages have resulted in superior analytical figures of merit and methods of background correction compared to conventional light sources. The most widely used lasers for atomic spectrometry include dye laser systems, optical parametric oscillator systems, and diode lasers. Three principal techniques employ lasers as light sources. Laser‐excited atomic fluorescence spectrometry (LEAFS) involves the use of laser light to excite atoms that emit fluorescence and serves as the analytical signal. Laser‐enhanced ionization (LEI) involves laser excitation of atoms to an excited state energy level at which collisional ionization occurs at a higher rate than from the ground state. Diode laser atomic absorption spectrometry (DLAAS) employs a DL as a source to excite atoms in an atom cell from the ground state to an excited state. The analytical signal is involves the ratio of the incident and transmitted beams. Recent applications of these techniques are discussed, including practical applications, hyphenated techniques employing laser‐induced plasmas, and work to characterize fundamental spectroscopic parameters. 相似文献
9.
10.
We consider the possible physical processes that may arise in a three-level atom when only two of its levels interact with a strong electromagnetic field and when the atomic transition frequency is nearly equal to once and twice the frequency of the laser field, respectively. There have been found pronounced cooperative effects in the spectrum of the two-level system, which is in resonance with the laser field, arising from the presence of the third level. The excitation spectra describing the transitions from the first excited state into the second excited state and from that to the ground state consist, apart from the two central peaks, of two pairs of sidebands which are induced by the laser field of the neighbouring system. Detailed expressions of the spectral functions for the physical processes of one- and two-photon resonance fluorescence have been derived and discussed in the limit of high photon densities. The excitation spectrum of the low frequency modes has been considered and discussed in detail. It is found that quantum beats in spontaneous emission may appear in the spectra of the one- and two-photon resonance fluorescence arising from the interference between the two atomic transition frequencies and the frequency of the laser field. The importance of the low frequency modes that occur in the processes in question has been pointed out. 相似文献
11.
Ramsey schemes with pulses of different lengths and with a composite pulse have been analyzed taking into account a finite width of the laser line and spontaneous relaxation of atomic levels. The optimal parameters of pulses corresponding to the maximum suppression of the excitation-related shift and the maximum resonance amplitude have been found for both schemes. According to the numerical results, spontaneous relaxation of the atomic levels and a finite width of the laser line must be taken into account in the calculation of the optimal parameters of the excitation pulses. The Ramsey scheme with a composite pulse is less sensitive to fluctuations of the Rabi frequency than the scheme with pulses of different lengths. 相似文献
12.
1 Introduction In 1 92 0 ,O .Sternmadeafirstpreliminarydeterminationofthevelocitydistributioninatomicbeamwithamechanicapparatus[1] .Afterthat,J.A .EldridgeandLammertmadebetterdeterminationsofthevelocitydistributionwitharotatingslotteddisk[1,2 ] .Theseearlyexperim… 相似文献
13.
In this paper, by using the detecting laser beam interacts with the atomic beam at a sharp angle and the Doppler frequency shift effect, the velocity distribution in cesium atomic beam is measured with a diode laser of narrow linewidth of 1 MHz. The effects of the atomic natural line width and cycling transition detecting factor on the measured results have been analyzed. Finally, the measured results have been compared with the theoretical calculation. 相似文献
14.
U. Klingbeil J. Kowalski F. Träger H. B. Wiegemann G. zu Putlitz 《Applied Physics A: Materials Science & Processing》1978,17(2):199-201
Lamb-dips have been observed in the weak calcium intercombination line by monitoring resonance fluorescence in an atomic beam
excited by light of a stabilized cw dye laser inside or outside the laser cavity. A highly sensitive detection scheme is described. 相似文献
15.
16.
F. Träger R. Neumann J. Kowalski G. zu Putlitz 《Applied Physics A: Materials Science & Processing》1977,12(1):19-22
A laser spectrometer with an intracavity atomic beam having a spectral resolution of about 3 MHz was developed and applied to atomic resonance fluorescence spectroscopy of the very weak Ca intercombination line λ=6573 Å. 相似文献
17.
在原子法激光同位素分离工程中,电子枪加热金属铀产生的原子蒸气的密度、速度以及温度等宏观量分布特性是非常重要的参数.为了分析电子枪功率和束宽对原子蒸气密度、速度、温度、质量通量和速度分布等物理特性的影响,采用直接MonteCarlo方法用柱坐标模拟了铀原子平面蒸发动力学过程.在电子枪加热方式下,蒸发源温度场不均匀,而且温度场随电子枪功率和束宽变化.着重研究这种变化对蒸气各种物理特性的影响.模拟结果表明,电子枪功率越高,蒸气径向宏观漂移速度越大,蒸发量越大;电子束束宽越窄,蒸发量越大.
关键词:
金属蒸发
原子法激光同位素分离
直接MonteCarlo
电子枪 相似文献
18.
We point out the influence of the different noise sources which occur in the detection of the fluorescence signal induced by a laser in an atomic beam. We have developed a theoretical model which takes account of the atomic shot noise, photon noise, laser-frequency noise and a partition noise linked to the imperfect detection of the fluorescence photons. The calculations have been performed for two- and three-level atomic systems. We detail the own contribution of each noise source and give some predictions concerning the value of the fluorescence signal to noise ratio. We determine predominance domains of each noise source which depend on the values of key parameters such as the atomic flux intensity and the laser spectral linewidth. We particularly show that the laser-frequency noise, which induces a coupling between the emission of fluorescence photons by various atoms, leads to a saturation of the S/N ratio for intense atomic fluxes. Moreover, we point out that the optical pumping process associated with a three level atomic system leads to an interesting laser-noise filtering effect. 相似文献
19.
The dynamics of interaction of laser radiation resonant with the transitions of D2 line in atomic Cs133 in the presence of an external magnetic field is studied. Populations of levels and dynamics of resonant fluorescence at scanning frequency of the laser radiation with linear and circular polarizations are considered. 相似文献
20.
本文给出一均匀增宽的三能级原子模型,在泵浦场和激光场同时存在时,讨论了双光子激光的增益、频率位移及弱泵浦时,稳态运转的阈值条件。同时讨论了相干泵浦对激光线宽的影响。其结果和仅存在非相干泵浦和泵浦不存在时的结果作了比较。 相似文献