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1.
The phenomenon of coherent population trapping for a four-level model of alkaline atoms with optical pumping by nonresonant
light is analytically investigated. Expressions for experimentally observed signals are derived for different variants of
induced magnetodipole transitions in the hyperfine structure of the ground state of atoms within the density matrix formalism.
No light-induced frequency shift of the signal of radio-optical resonance is observed irrespective of the radio field amplitude
and optical and thermal relaxation rates. It is demonstrated that with the use of modulation technique of phase detection
of experimentally observed signal, its discrimination power reaches a maximum under conditions of simultaneous modulation
of the pumping light intensity and radio-field frequency, which in principle is not observed in the classical two-level model
of optically oriented atoms in the magnetic resonance.
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Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 12–16, August, 2006. 相似文献
2.
V. V. Semenov 《Russian Physics Journal》1999,42(2):226-231
We have calculated the tensor component of the light shift for the frequency of the rf optical microwave resonance on the
magnetically independen 0−0 and 1, −1 transitions in rubidium-87 atoms under conditions of isotope filtering of the resonant
pump light. We have observed a difference between the temperatures of the filter cell at which a zero frequency shift is achieved
for the rf optical resonance for these transitions. We have noted that selective optical pumping on theD
1 lines is advisable when using a two-photon microwave transition in rubidium vapor in applications.
St. Petersburg State Technical University, St. Petersburg. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika,
Vol. 42, No. 2, pp. 86–90, February, 1999. 相似文献
3.
A. S. Shalin 《Journal of Applied Spectroscopy》2006,73(5):719-726
The integrodifferential equation method is used to study the spectrum of a nanoparticle colloid for the example of interaction
of three arbitrarily arranged dielectric particles made up of nonresonant atoms (the eigenfrequency of the transition is far
from the emission frequency) with incorporated barium atoms in an external optical radiation field. The effect on the light-scattering
properties of a nanosphere in the ensemble of its distant “neighbors” is studied; an additional peak associated with them
is observed as a frequency close to the resonance for an isolated nanosphere, which under certain conditions has higher intensity
than the main peak corresponding to optical near-field resonance in a two-particle system. The dependence of the spectrum
of the nanosized system on the geometric structure is studied, and it is shown that very precise tuning of the resonance frequency
is possible by varying the angular distribution of the particles.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 641–646, September–October, 2006. 相似文献
4.
5.
Q. Beaufils A. Crubellier T. Zanon B. Laburthe-Tolra é. Maréchal L. Vernac O. Gorceix 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):99-104
We develop a theoretical model to describe the
radio-frequency (rf) induced coupling of a pair of colliding atoms
to a Feshbach molecule when a magnetic field arbitrarily far from
the Feshbach resonance is modulated in time. We use the dressed atom
picture, and show that the coupling strength in presence of rf is
equal to the Feshbach coupling strength multiplied by the square of
a Bessel function. The argument of this function is equal to the
ratio of the atomic rf Rabi frequency to the rf frequency. We
experimentally demonstrate this law by measuring the rate of
rf-association of molecules using a Feshbach resonance in d wave
collisions between ultra-cold chromium atoms. 相似文献
6.
E. A. Protasov 《Applied magnetic resonance》2010,38(3):371-384
A nuclear magnetic resonance relaxometer operating in a continuous mode of the high-frequency low-power generation upon a
rapid approach to resonance, and consequent “passage” through resonance for the time of the signal decay has been developed.
In addition to the increased signal-to-noise ratio, the application of the periodic audio-frequency modulation of the magnetic
field under adiabatic conditions has enabled us to obtain the absorption derivative, which, in turn, has allowed us to record
the establishment of the thermodynamic equilibrium between spins and the lattice. Experimental data on the amplitude–relaxation
response of the relaxometer are given. Spin–lattice relaxation times of some proton-containing substances have been determined
as well. 相似文献
7.
8.
The optical pumping of Cs atoms with light of the D 1 line under magnetic resonance conditions is numerically calculated. This calculation is done to check the suggestion that an unexpectedly strong influence of the polarization of the pumping light on the resonance signals of transverse alignment, which we observed experimentally, is caused by the coupling between orientation and alignment by means of the magnetic field and/or the pumping light. This suggestion has been confirmed: upon circularly polarized pumping, the shape of the signal line of transverse alignment proved to be similar, as well as in the experiment, to the shape of the signal line of transverse orientation and was sharply different from the shape of the line of alignment observed upon linearly polarized pumping. For metastable 23 S 1 4He atoms, in accordance with the experimental data, the calculated shape of the signal line of transverse alignment is found to be independent of the polarization of the pumping light. The calculations also confirm the possibility of a reverse effect: the influence of alignment on orientation, which manifests itself in the occurrence of orientation upon pumping with unpolarized light under magnetic resonance conditions. For Cs atoms exposed to a field of ~0.6 Oe, the largest contribution to this effect is yielded by the field coupling of orientation and alignment, whereas, for metastable 23 S 1 4He atoms, the largest contribution is made by the light coupling of these polarization moments. 相似文献
9.
S. P. Dmitriev N. A. Dovator R. A. Zhitnikov V. A. Kartoshkin V. D. Mel’nikov 《JETP Letters》1997,65(5):399-401
An experiment on the observation of spin polarization of metastable helium atoms interacting with optically oriented sodium
atoms under continuous rf discharge conditions is described. Laser radiation with alternating-sign circular polarization,
tuned to the resonance excitation of the 32
S
1/2–32
P
1/2 transition in Na atoms, is used as the source for optical pumping of ground-state sodium atoms.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 5, 385–387 (10 March 1997) 相似文献
10.
We have solved a self-consistent problem on interaction of two dipole atoms located at an arbitrary distance from each other
with the field of a quasiresonance light wave, whose intensity is sufficient for the system to manifest nonlinear properties.
The atoms are considered as two-level systems described by means of Bloch optical equations, while the field inside of the
system includes both Coulomb and retarded parts. We consider a situation where atoms are identical and the distance between
them is much smaller than the length of an outer light wave. The distribution of an electric field both inside of a small
object and outside of it is found numerically. It is shown that the amplitude of the electric field in a wave zone depends
substantially on the frequency of the external field and interatomic distance, while the field distribution differs from the
field pattern of an electric dipole. At definite values of the external field intensity an optical multistability is a feature
of the system under investigation. We have elucidated the conditions under which the multistability is manifested in the present
system. The results obtained are considered as the near-field effect in the optics of small objects, which makes it possible
to investigate the structure of small objects by means of optical radiation.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 375–378, May–June, 2000.
The present work was supported by the Russian Foundation for Fundamental Research (grant 98-02-16035) and by a grant from
the Federal Purpose-Oriented Program “Integration.” 相似文献
11.
V. V. Semenov 《Journal of Applied Spectroscopy》1997,64(1):72-76
The conditions for optimization of the regimes of optical pumping in optically oriented alkali atoms under total overlap of
the components of low-frequency Zeeman and multiphoton shf resonances in the ground state are considered. The difference in
the contribution of the light of pumping by the D1 line to the rates of longitudinal and transverse relaxation is shown in terms of a two-level model of rubidium and cesium
atoms, and values of the optimum pumping rate corresponding to the maximum of the quality factor of the recorded signal have
been calculated. Experimental estimation of the relaxation rates was made by the signal of low-frequency Zeeman resonance
in optically oriented rubidium and cesium atoms under conditions of homogeneous and inhomogeneous magnetic fields. It is shown
that in pumping by the D1 line from a lamp source and with balance of the dark times of the longitudinal and transverse relaxation the optimum pumping
rate differs significantly from its values known from the literature.
St. Petersburg State Technical University, 29, Politekhnicheskaya St., St. Petersburg, 195251, Russia. Translated from Zhurnal
Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 71–75, January–February, 1997. 相似文献
12.
We study the behaviour of atoms in a field with both static magnetic field and radio frequency (rf) magnetic field. We calculate the adiabatic potential of atoms numerically beyond the usually rotating wave approximation, and it is pointed that there is a great difference between using these two methods. We find the preconditions when RWA is valid. In the extreme of static field almost parallel to rf field, we reach an analytic formula. Finally, we apply this method to 87 Rb and propose a guide based on an rf field on atom chip. 相似文献
13.
本文报道了一种基于激光抽运射频共振的铯原子磁力仪. 通过圆偏振光将铯原子抽运到暗态, 实现偏极化. 外磁场存在时, 原子磁矩将以拉莫尔频率绕外磁场进动. 在共振射频磁场的作用下, 原子被去极化而重新吸收光子. 通过探测出射光光谱可以测得拉莫尔频率进而得到外磁场的信息. 本文通过运用自制的894 nm 外腔半导体激光器, 建立了激光稳频装置和低噪声磁场测量环境, 实现了一种基于铯原子激光抽运射频共振的磁力仪. 通过磁力仪参数优化以及闭环测量, 磁力仪测量的外磁场达到了19 fT/Hz1/2的极限灵敏度和1.8 pT/Hz1/2的本征灵敏度, 空间分辨率小于2 cm.
关键词:
光抽运
塞曼效应
光探测磁共振
磁力仪 相似文献
14.
Kroner M Weiss KM Biedermann B Seidl S Manus S Holleitner AW Badolato A Petroff PM Gerardot BD Warburton RJ Karrai K 《Physical review letters》2008,100(15):156803
We demonstrate optically detected spin resonance of a single electron confined to a self-assembled quantum dot. The dot is rendered dark by resonant optical pumping of the spin with a laser. Contrast is restored by applying a radio frequency (rf) magnetic field at the spin resonance. The scheme is sensitive even to rf fields of just a few microT. In one case, the spin resonance behaves as a driven 3-level lambda system with weak damping; in another one, the dot exhibits remarkably strong (67% signal recovery) and narrow (0.34 MHz) spin resonances with fluctuating resonant positions, evidence of unusual dynamic processes. 相似文献
15.
The excitation of axial radio-frequency (rf) magnetic induction by an axial rf current is observed in a conductor with circular
magnetic anisotropy when a weak magnetizing field is applied. The conductor is an amorphous cobalt-based wire, which exhibits
azimuthal magnetic anisotropy. It serves as the central conductor in a coaxial line. The axial rf magnetic induction produces
an emf in an induction coil coaxial to the conductor. The induction coil is part of a matched receiving circuit. The power
conversion coefficient is as high as tens of percent. The measurements demonstrate the high sensitivity of the conversion
coefficient to an external field. The theory of ferromagnetic resonance faithfully describes the results of the observations.
Zh. Tekh. Fiz. 69, 58–63 (March 1999) 相似文献
16.
17.
We describe an alkali-metal magnetometer for detection of weak magnetic fields in the radio-frequency (rf) range. High sensitivity is achieved by tuning the Zeeman resonance of alkali atoms to the rf frequency and partially suppressing spin-exchange collisions in the alkali-metal vapor. We demonstrate magnetic field sensitivity of 2 fT/Hz(1/2) at a frequency of 99 kHz with a resonance width of 400 Hz. We also derive a simple analytic expression for the fundamental limit on the sensitivity of the rf magnetometer and show that a sensitivity of about 0.01 fT/Hz(1/2) can be achieved in a practical system with a measurement volume of 200 cm3. 相似文献
18.
The results of an experimental and theoretical investigation of strong turbulence produced by an external rf field in the
plasma of a beam-plasma discharge are presented. The modulation instability of a rf electric field, perpendicular to a constant
magnetic field, in the frequency range between the lower-hybrid and ionic Langmuir frequencies, has been investigated. It
is shown that the low-frequency fields can be used to control beam relaxation.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 9, 608–612 (10 November 1996) 相似文献
19.
The orientational frequency shift of the UHF radio-optical resonance in the 87Rb vapor with a selective optical pumping by laser and lamp sources is studied experimentally and theoretically. A leading role of the tensor component of the light shift is noticed for both excitation modes, and a modulation technique of the resonance frequency orientation shift suppression is demonstrated. We show that it is necessary to ensure a constancy of the angle between the pump light direction and the external magnetic field vector when using a rubidium quantum discriminator based on moving and rotating carriers. 相似文献
20.
A contact-free method of modulation spectroscopy of semiconductor heterostructures is developed. The method employs the effect
of an intensity-modulated rf or microwave field on the reflection of the probe light and makes it possible to investigate
electron-hole interaction effects in different layers of a heterostructure. A model is proposed which explains the characteristic
features of the rf-modulated optical reflection spectra observed on selectively doped GaAs/AlGaAs heterostructures is proposed.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 3, 217–221 (10 February 1998) 相似文献