Radiation from an atom located in an external electromagnetic field

A. P. Kazantsev

И. Д. Феранчук, A. A. Ivanov, Van-Hoang Le +1 more

V. N. Streltsov

А. Ч. Измайлов

The possibility of controlling the motion of microparticles by means of external electromagnetic fields (nonresonance laser radiation, in particular) that induce potential wells for such particles, which are characterized by fixed spatial distribution but deepen over time to a certain level, are analyzed. It is assumed that the particles are located in high vacuum and are affected by nondissipative external forces. Slowing down of relatively fast particles when they pass through the discussed potential wells is shown. Such slowing down of particles is demonstrated using a nonresonance laser beam with intensity increasing over time as an example. Specific features of particle dynamics in the electromagnetic fields under consideration in the case of a one-dimensional rectangular potential well are studied in detail based on simple analytical relations derived from the fundamental equations of classical mechanics. The methods of particle cooling and localization demonstrated in the present work can substantially increase spectroscopy resolution of various microparticles, including, under certain conditions, atoms and molecules.

Vl. V. Kocharovsky, Vl. V. Kocharovsky, Alexey A. Belyanin

It is shown that spontaneous emission of an excited atom is suppressed, and electromagnetic instability of the ground state is possible, if an atom is located in the vicinity of an active medium which amplifies the propagating radiation. The effect is due to a modified and phase-shifted near field of an oscillating atomic dipole, which prevails over the usual radiation reaction field related to the wave zone. The necessary conditions for the reversal of the total electromagnetic back reaction are found, and possible experimental realizations are discussed.