Scattering of the wavepacket of an atom by a resonance standing light wave

V. A. Grinchuk, A. P. Kazantsev, E. F. Kuzin +4 more

A. P. Kazantsev, Gregory I. Surdutovich, Valery P. Yakovlev +1 more

Vladimir G. Minogin

V. A. Grinchuk, I. A. Grishina, E. F. Kuzin +3 more

In this paper we present some new results concerning the observed anomalous frequency properties of the process of the neutral atom scattering in the standing light wave field near the reflecting mirror. The investigations were carried out using the method of scattering of the sodium atomic strip beam, intersecting at right angle the region of the standing light wave field. The standing light wave field was formed by two counterpropagating waves of resonant laser radiation -- incident and reflected from the mirror, mounted at a distance of about 1 cm from the atomic beam. The coherence length of the laser radiation was about 10 cm, that's why the interaction of atoms with the field of two counterpropagating light waves was coherent. The width of the strip atomic beam (a equals 0.02 cm) was much less than the distance to the mirror. The specific feature of the given setup is the use of pulsed laser radiation with the duration (tau) less than 1/(gamma) ((gamma) -1- the time of resonant level spontaneous decay), so the atoms are scattered only due to the induced light pressure force. In this paper the detailed investigation of the distance R influence on the scattering process was carried out. With this purpose the mirror was mounted at different distances from the atomic beam. (truncated)

Mikhail Vladimirovich Fedorov, MA Efremov, VP Yakovlev +1 more

The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic scattering in the case of a sufficiently long interaction time.

Maxim A. Efremov, Mikhail Vladimirovich Fedorov

The Kapitza-Dirac effect (KDE), or the scattering of electrons by a standing light wave, is considered quantum mechanically with electron states before scattering taken in the form of wavepackets with homogeneously distributed `centres of mass'. The angular distribution functions of electrons after scattering and the average angle of scattering are found. This approach is used to establish the applicability conditions of purely classical, purely quantum-mechanical and intermediate results in the theory of KDE, as well as to describe some new regimes of scattering, characteristics of which depend explicitly on the size of the wavepackets before scattering.