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1.
Summary The relaxation of quadrupole orientation (alignment) in an optically pumped alkali vapour is theoretically studied by taking
into account the relaxation processes by alkali-buffer gas, alkali-alkali with spin exchange and alkali-cell wall (diffusion
process) collisions. The relaxation transients of the quadrupole orientation are obtained by introducing a first-order weak-pumping
approximation (intermediate pumping) less restrictive than the usually considered (zeroth order) one.
Riassunto Il rilassamento dell’orientamento quadrupolare (allineamento) di un vapore alcalino pompato otticamente è studiato dal punto di vista teorico prendendo in considerazione i processi di rilassamento mediante collisioni base alcalina-gas tampone, base alcalina-base alcalina con scambio di spin e base alcalina-parete della cella (processo di diffusione). I transienti di rilassamento dell’orientamento quadrupolare sono ottenuti introducendo un’approssimazione di prim’ordine con pompaggio debole (pompaggio medio) meno restrittiva di quella considerata solitamente (di ordine zero).
Резюме Теоретически исследуется релаксация квадрупольной ориентации в оптически накаченных парах щелочных металлов, учитывая релаксационные процессы взаимодействия буферного газа и атомов щелочного металла, столкновения атомов щелочного металла между собой с изменением ориентации спина и столкновения атомов щелочного металла со стенкой ячейки (процесс диффузии). Обнаружены релаксационные переходные процессы для квадрупольной ориентации, вводя промежуточную накачку.相似文献
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We have demonstrated an optically pumped continuous wave Cs vapor laser with an input power to output power slope efficiency of 81%. The laser power was 0.35 W for an input power of 0.57 W, yielding an overall optical efficiency of 63%. 相似文献
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以电光调Q的Nd:YAG激光器为泵浦源,以磷酸氧钛钾(KTP)为非线性晶体,搭建了调谐范围为750~800 nm的光参量振荡器。信号光在中心波长780.2 nm处获得单脉冲能量113 mJ、脉宽15.43 ns、光斑直径5.5 mm的输出。用光栅单色仪测量信号光光谱宽度(FWHM)为0.38 nm。信号光通过120 ℃的铷蒸气池,观察到清晰的荧光轨迹。证明信号光能有效泵浦铷蒸气,可为铷激光器提供峰值功率7 MW的高强度脉冲泵浦源,进而研究铷激光器在高强度泵浦条件下的动力学过程和基础物理机制。 相似文献
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以电光调Q的Nd:YAG激光器为泵浦源,以磷酸氧钛钾(KTP)为非线性晶体,搭建了调谐范围为750~800 nm的光参量振荡器。信号光在中心波长780.2 nm处获得单脉冲能量113 mJ、脉宽15.43 ns、光斑直径5.5 mm的输出。用光栅单色仪测量信号光光谱宽度(FWHM)为0.38 nm。信号光通过120 ℃的铷蒸气池,观察到清晰的荧光轨迹。证明信号光能有效泵浦铷蒸气,可为铷激光器提供峰值功率7 MW的高强度脉冲泵浦源,进而研究铷激光器在高强度泵浦条件下的动力学过程和基础物理机制。 相似文献
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S. Bhattacharyya S. G. Nakhate 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,55(1):9-15
We have observed superfluorescence (SF) on five atomic transitions at
visible wavelengths 633.58, 635.00, 640.09, 640.61 and 736.22 nm in Doppler
broadened gas of europium (Eu) atom. The nanosecond SF pulses were observed
by longitudinally pumping Eu vapor column with a pulsed dye laser to upper
states 4f65d6s2, 8D7/2at 346.79 nm and 4f75d6p,
10F5/2at 348.73 nm from the ground state 4f76s2,
8S7/2. High optical conversion efficiency ≈10% was
measured for these SF transitions. Our experiment deals with the large
sample multilevel SF in the regime where the length of the excited
column L is greater than the maximum value of the Arecchi-Courtens
length (Lc). The observed variation of SF peak intensity (Ifl) and time
delay for SF evolution (τD) with number of atoms in the excited
state (N) resemble theoretically predicted SF scaling laws for transverse
excitation, namely Ifl∝N and tD μ 1/?N\tau_D \propto 1/{\sqrt N} although the experimental condition
is similar to the swept excitation. This could be due to the Rabi frequency
associated with the pump transition which is comparable to the SF delay time
precluding the initiation of SF at different times along the sample and
results in transverse (instantaneous) excitation. The experimental τD
values were found to be in agreement with the quantum mechanical
calculations describing SF. 相似文献
11.
Summary The effects of a static magnetic field on the relaxation of an alkali vapour by isotropic collisions with very short correlation
time are studied.
relaxation transients are specifically considered. The analytical approach to the problem allows us to get the number and
structure of eigenobservables, both the subset of degenerate eigenobservables, whose relaxation is not affected by the magnetic
field, and the subset of nondegenerate eigenobservables with magnetic-field-dependent relaxation rates. First-order approximations
to modified relaxation rates are also analytically derived.
Riassunto Si studiano gli effetti di un campo magnetico statico sul rilassamento di un vapore alcalino mediante collisioni isotrope con tempo di correlazione molto breve. L’approccio analitico al problema ci permette di ottenere il numero e la struttura di autoosservabili, sia il sottogruppo delle autoosservabili degenerate, il cui rilassamento non è influenzato dal campo magnetico, sia il sottogruppo di autoosservabili non degenerate con valori di rilassamento dipendenti dal campo magnetico. Si derivano anche analiticamente approssimazioni di prim’ordine ai valori di rilassamento modificati.
Резюме Исследуется влияие статического магнитного поля на релаксацию пароь щелочных металлов в результате изотропных соударений с очень малым временем корреляции. В частности, рассматривается релаксационный переходной процесс. Аналитический подход к проблеме позволяет получить число и структуру собственных значений: подсистему вырожденных собственных величин, релаксация которых не зависит от магнитного поля и подсистему невырожденных собственных значений, для которых релаксация зависит от магнитного поля. Аналитически выводятся приближения первого порядка для модификации релаксационных переходов.相似文献
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Resonance reflection of light from the interface between a dielectric and an alkali vapor is studied. Two cases are considered in which a laser light beam is polarized either parallel or perpendicular to the plane of incidence. Upon scanning of the frequency of the incident laser radiation, in the first case, the reflection conditions vary from approximately the conditions of Brewster reflection to the conditions characteristics of total internal reflection. In the second case, the Brewster reflection conditions are not realized, and the variations in the intensity of the reflected light observed upon frequency scanning are smaller. The rotation of the plane of polarization and the laser frequency tuning make it possible to rapidly switch between these reflection conditions. 相似文献
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The observed asymmetry of tuning curves of a 70.6 μm CH3OH laser is interpreted as a consequence of unidirectional amplification in the optically pumped gas, a quantum mechanical double resonance effect. The occurrence of this effect. was verified by FIR gain measurements. 相似文献
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W. Kamke 《Physics letters. A》1975,55(1):15-16
Nuclear spin polarization in diatomic potassium molecules is produced by polarization transfer between dimers and optically pumped potassium atoms. NMR signals from K2-molecules have been measured. Linewidth studies give information on relaxation processes of nuclear magnetic polarization. 相似文献
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M. Tacke 《International Journal of Infrared and Millimeter Waves》1983,4(3):451-461
Summary A procedure for computing the shape of the wavefronts in waveguide lasers with inhomogeneous gain has been found. Its application to an optically pumped FIR laser shows that the inhomogeneous pump beam intensity will lead to sizeable effects in the output beam geometry.The same treatment is possible for other types of waveguide lasers, too. It is probable that in most cases the first order approximation is satisfactory. If waveguide losses have to be included, this can easily be accounted for by replacing G in equation (4) by (G-). 相似文献
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A. Vass B. W. Davis W. J. Firth C. R. Pidgeon 《Applied physics. B, Lasers and optics》1982,29(2):131-134
Direct frequency measurements of a13CO2/15NH3 OPFIRL output show that laser pulling effects give shifts of a few MHz, which agree well with a density matrix calculation. 相似文献
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W. A. Bookless L. W. Hrubesh C. G. Stevens E. A. Rinehart 《International Journal of Infrared and Millimeter Waves》1982,3(2):171-187
We report the generation of tunable far-infrared radiation by the optical pumping of potassium metal vapor to the13p Rykberg state. Subsequent cascade by stimulated emission is measured at several wavelengths between 76 and 146 cm–1 with a conversion quantum efficiency of greater than 10 percent. Emission observed in this region are tuned up to 18 GHz by the application of a pulsed Stark field across a parallel-plate heat pipe. Cascade branching to the 11d to 10f transition at 146 cm–1 is observed which can be tuned up to 7 cm–1 in our device. Similar branching following excitation up to the 18 p state is shown to provide almost complete tunability in the far-infrared region.Work performed under the auspices of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48. 相似文献
18.
The nuclear polarization of an optically pumped3He target can be determined by optical methods if one makes some assumptions on the kinetics of the pumping process. Experiments and calculations have been carried out to examine whether these postulates are permissible. A good agreement between experiments and theory confirms the correctness of the assumptions and consequently justify the determination of the nuclear polarization by optical methods. 相似文献
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Several new laser lines using optically pumped deuterated methanol molecules have been discovered. These not only increase
the spectral coverage of pumped methanol isotopes but may assist in the assignment of a molecular structure. 相似文献
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V. Candelier V. Giordano A. Hamel G. Théobald P. Cérez C. Audoin 《Applied physics. B, Lasers and optics》1989,49(4):365-370
Results obtained in an experimental optically pumped cesium beam frequency standard in which a single semiconductor laser is used for the state selection and the atom detection are reported. The separation between the two interaction regions is equal to 21 cm. This gives a 500 Hz linewidth which is observed with a signal to noise ratio equal to 10,000 in a 1 Hz noise bandwidth. A quartz crystal oscillator is frequency controlled by the atomic transition. The measured short term frequency stability is given by y()=2×10–12–1/2 for 1 s<500 s. Prospects for improvement of this frequency stability are discussed. 相似文献