共查询到20条相似文献,搜索用时 31 毫秒
1.
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
2.
Imaging an atomic beam using fluorescence 总被引:1,自引:0,他引:1
A fluorescence detection scheme is applied to image an atomic beam. Using two laser diodes as the sources of detection light and pumping light respectively, the fluorescence image of the atomic beam is then observed by a commercial CCD-camera, which is corresponding to the atomic state and velocity distribution. The detection scheme has a great utilization in the experiments of cold atoms and atomic optics. 相似文献
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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
5.
K. Yasutake H. Ohmi M. Shimizu A. Takeuchi H. Kakiuchi K. Yoshii Y. Mori 《Applied physics. B, Lasers and optics》2000,71(6):787-793
A velocity spectrometer for a neutral atomic beam has been developed to prepare a monovelocity atomic beam. In order to disperse
a relatively fast atomic beam according to its longitudinal velocity, a magnetic quadrupole lens with a large magnetic gradient
has been used. The device was made using NdFeB permanent magnets. The magnetic gradient in the quadrupole was measured to
be sufficiently large (1 T/cm) and uniform along the radial direction. The resonance fluorescence spectra of the Li atomic
beam after passing through the magnetic quadrupole lens have been measured by using a single-mode tunable laser. From the
peak shift of the fluorescence spectrum, the exerted force on Li atoms by the magnetic lens was 8160 times as large as the
acceleration of gravity. Using the present spectrometer, we have measured the longitudinal velocity distribution of the thermal
Li beam at 800 °C, which was in good agreement with the result from the fluorescence spectra. It is expected that a monovelocity
Li atomic beam of 1000 m/s with a velocity spread narrower than 1% can be easily formed with a compact experimental arrangement
using the developed velocity spectrometer. In this case, the available flux given as a fraction of the incident Li flux is
estimated to be about 1%. A high-velocity resolution of 0.03% is expected at the available fractional flux of about 0.01%.
Received: 5 June 2000 / Revised version: 14 August 2000 / Published online: 8 November 2000 相似文献
6.
The lifetimes of atomic CoI states have been determined using the delayed coincidence technique. A tunable dye laser pumped by a nitrogen laser was employed for the excitation of cobalt atoms in an atomic beam. The lifetimes were derived from the time dependent fluorescence intensity of the observed lines after the excitation. For the measurement of the lifetimes of thee 4 F 9/2,f 4 F 9/2 andf 4 F 7/2 levels a two step excitation was applied. In case of overlapping measurement we find our results to be in good agreement with those reported by Becker [1]. 相似文献
7.
Hoseong Kim Jaeho Choi Kook-Nyung Lee Yong-Kweon Kim Eun-mi Kim Byung-Gee Kim 《Optics and Lasers in Engineering》2006,44(11):1198-1208
A novel optical arrangement for fluorescence detection that employs spatial separation as well as spectral filter to increase the signal to noise ratio is proposed. Using a prism and two mirrors, the elliptical laser beam of a laser diode, as an excitation light, is homogenized and the transmitted excitation light is separated from the fluorescence not to reach the collecting optics. Uncooled CCD can capture the fluorescence image of up to 40 fluorescently-labeled protein patterns without scanning or mechanical translation. This paper presents the simulation, construction and measurement results of the developed optical system. The measurements show that the combination of prism and mirrors converts the excitation light from the laser diode to uniform illumination on the specimen, and provides the separation between excitation and fluorescence light to give high signal to noise ratio. It is also possible to assay various protein concentrations ranging from 1000 to 10 ng/ml reliably. We believe that the proposed fluorescence detection system can be used to build a commercially valuable, low cost, hand-held or miniature fast detection device for point-of-care applications. 相似文献
8.
P. Valente H. Failache A. Lezama 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(2):133-140
We have observed resonant features in the spectrum of the fluctuations of a linearly polarized diode laser beam transmitted
through a rubidium vapor cell, corresponding to the evolution of the atomic spin in the presence of a constant magnetic field.
The observed resonances occur at a noise frequency corresponding to twice the Larmor frequency of ground state rubidium atoms
and are due to two-photon Raman processes involving the carrier frequency and the noise sideband. We observed noise resonances
for frequencies of the order of one MHz via heterodyne detection. Due to nonlinear Faraday rotation, we detected emitted light
with polarization orthogonal to the incident field. The influence of the laser light fluctuations on the transmitted light
noise spectrum was investigated by using two diode laser sources with different spectral bandwidths. The observed features
are in qualitative agreement with a semiclassical theoretical model that treats laser fluctuations up to first order. 相似文献
9.
Yun Long Zhuanxian Xiong Xi Zhang Mengjiao Zhang Baolong Lv Lingxiang He 《中国光学快报(英文版)》2014,12(2):21401-37
The laser cooling of ytterbium(Yb) atoms needs a 399-nm laser which operates on the strong1S0-1P1 transition and can be locked at the desired frequencies for different Yb isotopes.We demonstrate a frequency locking method using the fluorescence spectrum of an Yb atomic beam as a frequency reference.For unresolved fluorescence peaks,we make the spectrum of the even isotopes vanish by using the strong angular-dependence of the fluorescence radiations;the remained closely-spaced peaks are thus clearly resolved and able to serve as accurate frequency references.A computer-controlled servo system is used to lock the laser frequency to a single fluorescence peak of interest,and a frequency stability of 304 kHz is achieved.This frequency-locked laser enables us to realize stable blue magneto-optic-traps(MOT) for all abundant Yb isotopes. 相似文献
10.
The beam—gas-laser two-step excitation technique of a fast ion beam is used for precision measurements of atomic life-times. By observing the decay of the purely laser induced fluorescence radiation, the lifetimes of eight fine-structure levels 2p2 to 2p9 in the NeI 2p53p configuration were measured with total standard deviations of 0.2 to 0.5%. 相似文献
11.
We report here the development of collinear laser spectroscopy (CLS) system at VECC for the study of hyperfine spectrum and isotopic shift of stable and unstable isotopes. The facility is first of its kind in the country allowing measurement of hyperfine splitting of atomic levels using atomic beams. The CLS system is installed downstream of the focal plane of the existing isotope separator online (ISOL) facility at VECC and is recently commissioned by successfully resolving the fluorescence spectrum of the hyperfine levels in \(^{85,87}\)Rb. The atomic beams of Rb were produced by charge exchange of 8 keV Rb ion beam which were produced, extracted and transported to the charge exchange cell using the ion sources, extractor and the beam-line magnets of the ISOL facility. The laser propagating opposite to the ion / atom beam direction was allowed to interact with the atom beam and fluorescence spectrum was recorded. The experimental set-up and the experiment conducted are reported in detail. The measures needed to be carried out for improving the sensitivity to a level necessary for studying short-lived exotic nuclei have also been discussed. 相似文献
12.
An Experiment to Demonstrate the Hyperfine Splitting of Atoms in a Lecture Hall The detection of laser induced fluorescence from a thermal atomic beam allows in a simple way for the observation of the hyperfine splitting of ground and excited Na-atoms. A suitable experimental setup is able to show in a lecture hall not only the atomic beam itself but also the consequences of electron and nuclear spin. The laser light used is transmitted from the laser in the laboratory into the lecture hall by a fiber glass cable. The experiment is able to show also the effects of optical pumping and, if additionally an external magnetic field is applied to the observation region, the Zeeman effect. 相似文献
13.
激光诱导击穿光谱技术是一种新型的原子光谱分析技术,具有实时快速、 多元素同时分析和样品预处理简单等特点,从一出现便受到研究人员的广泛关注,但分析灵敏度差一直是限制该技术发展的重要因素。基于共振激发的激光诱导击穿光谱技术将原子荧光光谱技术和激光诱导击穿光谱技术结合,对目标元素进行选择性激发,可以大幅提高激光诱导击穿光谱技术的分析灵敏度,极大地拓展了LIBS技术在痕量元素检测领域的应用。本文综述了基于共振激发的激光诱导击穿光谱技术的研究进展,介绍了激光诱导等离子体中荧光光谱的产生过程以及基于共振激发的激光诱导击穿光谱技术的基本类型和基础原理,详细分析了烧蚀激光能量、 共振激发激光能量和波长、 烧蚀激光和共振激发激光之间的延时以及光谱采集门宽对光谱增强效果的影响,阐述了其在冶金、 环境监测、 同位素检测等领域的应用现状和存在的问题,并对其未来发展前景进行了展望。 相似文献
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Six atomic spectral lines induced by NaRb molecules in the absorption spectrum of sodium-rubidium vapour have been observed in the wavelength range 611–641 nm. For sodium-rubidium vapour, the laser induced fluorescence spectra at laser wavelengths 616.04 and 615.81 nm and the excitation spectra at sodiumD-lines with the laser scanning in the range 613.9–616.9 nm have also been measured. The possible mechanisms for the appearance of these absorption lines are discussed. 相似文献
16.
常见食用油和煎炸食用油的激光诱导荧光光谱特性 总被引:1,自引:0,他引:1
为了实现地沟油的快速检测,利用激光诱导荧光探测技术搭建了食用油类快速检测系统。对多种食用油和煎炸食用油(地沟油的一种)进行了光谱采集,建立了多种食用油和煎炸食用油的荧光光谱数据库,发现煎炸食用油的特征荧光光谱与常见食用油之间存在较大差异,在此基础上利用主成分分析法和BP神经网络实现了油类识别、地沟油的快速检测,总体识别率高达97.5%。实验证明激光诱导荧光光谱技术具有快速非接触和灵敏度高等优点,与BP神经网络相结合能够实现油类的快速识别,成为地沟油快速检测的一种新方法。 相似文献
17.
碳涂层对激光诱导金属等离子体辐射强度的影响 总被引:2,自引:2,他引:0
为了降低样品表面对激光束的反射率,提高激光诱导等离子体的辐射强度,文章报道了一种在钢样品表面涂抹碳层的方法.实验结果表明,当一束高能量激光(~25 D作用于覆盖有适当厚度碳涂层的钢样品时,激光等离子体发射的谱线强度提高了10%~28%.为解释谱线强度增强的机理,测量了等离子体的激发温度.此外,实验研究还发现,更强的原子发射光谱出现在激光等离子体径向的1 mm处,而不是在其中心位置. 相似文献
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19.
研究了激发光增强时其对荧光关联谱(FCS)测量的影响. 强激发光产生的饱和激发会改 变激光诱导荧光的空间分布函数,从而影响FCS的测量结果. 首先根据饱和吸收的物理模型,推导出强激发光情况下有效探测区域变化的定量公式,获得了FCS测量所得到的粒子数和扩散时间与饱和激发光强和激光光强的函数关系,并用于消除饱和吸收造成的系统误差.采用Monte-Carlo模拟方法和实验,对理论分析结果进行了验证. 这将有助于完善FCS分析方法的理论模型,为高激发光强度下的FCS探测提供依据.
关键词:
荧光关联谱
饱和激发
Monte-Carlo模拟 相似文献
20.
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