arXiv:1612.05411

Macroscopic magnetic field generated in laser atom interaction

Swarupananda Pradhan

Published Dec 16, 2016• 2 citations

Abstract

We observe shift in the zero magnetic field resonance as the handedness of resonantly interacting circularly polarized light is changed. The characteristic of the shift resembles with the Zeeman light shift that arises due to interaction of non-resonant circularly polarized light with atom. However many attributes of our observed resonant phenomena like dependence on buffer gas, saturation of the shift with light intensity and involved time constant in evolution of the shift contradicts to the fictitious magnetic field model. We propose collective alignment of atomic magnetic moment giving rise to a real magnetic field as a possible mechanism behind the observed shift. The characteristic changes in the signal profile with respect to the three axis magnetic field have been established that can reveal many subtle issues pertaining to the phenomenon.

DOI: 10.48550/arxiv.1612.05411

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arXiv:1612.05411

Macroscopic magnetic field generated in laser atom interaction

Swarupananda Pradhan

Published Dec 16, 2016• 2 citations

arXiv HTML PDF

Abstract

DOI: 10.48550/arxiv.1612.05411

Related papers

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Physical Review AFeb 1, 1972265 citations

D1

and

D2

frequencies, with the size of the detuning from the

D2

resonance being twice that from the

D1

resonance, and it is circularly polarized to produce an ac Stark shift that takes the form of a pure Zeeman shift. Slow rubidium atoms are extracted from a magneto-optical trap and then spin polarized. The atoms traversing the laser-intensity gradient on one side of the Gaussian beam profile show deflections that depend on the atomic spin state and the laser polarization. When the laser-beam axis is aligned with the slit that defines the atomic beam, we observe focusing and defocusing of the atomic beam.

D1

and

D2

transition frequencies, with the size of the detuning from the

D2

resonance twice that from the

D1

resonance. The direction of the effective magnetic field is along the laser propagation axis, and its magnitude is proportional to the vector polarizability of the atom and to the laser intensity. We use stimulated Raman spectroscopy on an optically pumped slow atomic beam from a magneto-optical trap to measure the vector polarizability and saturated absorption spectroscopy to show that the scalar polarizability vanishes at the particular detuning.

{\mathcal{H}}_{e}

which depends on the polarization and spectral profile of the incident light. In order to check the structure of

{\mathcal{H}}_{e}

, we have performed a detailed experimental study of the ground-state energy sublevels of various kinds of atoms perturbed by different types of nonresonant light beams. Attention is paid to the modification of the Zeeman structure due to

{\mathcal{H}}_{e}

. We have been able to obtain experimentally in the ground state of

^{199}\mathrm{Hg}

^{201}\mathrm{Hg}

, and

^{87}\mathrm{Rb}

, Zeeman light shifts that are larger than the width of the levels due to the thermal relaxation. The removal of the Zeeman degeneracy in zero external field, due to a nonresonant light irradiation, is observed by different optical-pumping techniques; the full Zeeman diagram of the perturbed atoms is also determined when a static field ${\stackrel{\ensuremath{\rightarrow}}{\mathrm{H}}}_{0}$ is added. We have checked that the effect of

{\mathcal{H}}_{e}

can be described in terms of fictitious static electric or magnetic fields. These fictitious fields can be used to act selectively on a given atomic level.