Evidence of self-polarization of the ground degenerate atomic level during optical pumping on a two-quantum transition

A. P. Kazantsev, Vladimir S. Smirnov, A. M. Turmaikin +1 more

N. L. Kosulin, Anatolii M Tumaikin

Julie A. Byrne, Ildar R. Gabitov, Gregor Kovačič

Vasyl P. Kunets

The nonlinear optical transmission of CdSe single crystals and saturation thresholds at different polarizations of the pumping wave are studied in a range of the exponential absorption tail. Theoretical calculations performed in the framework of a two-level model with the twofold degenerate ground state corresponding to the optical transitions in E ⟂ C and E‖ C polarizations are also presented. Results obtained for the absorption saturation regime clearly witnesses in favour of the polarization self-action effect and relaxation processes between transitions polarized orthogonally.

Christopher Feuillade, P. R. Berman

A theory of saturation spectroscopy is developed which accounts for effects of level degeneracy. The theory can be applied to those situations in which a pump laser field of arbitrary strength and polarization acts between two manifolds of degenerate or nearly degenerate atomic levels, while a probe laser field of arbitrary strength and polarization acts between a coupled manifold of levels. As such, this theory of "three-level" systems could, in principle, include effects arising from level degeneracy, optical pumping, atomic motion, transient laser fields, different polarizations and strengths for pump and probe fields, and atomic transit across the laser fields. The present calculation, however, is limited to a study of optical pumping and field polarization effects for pump fields of arbitrary strength and weak probe fields interacting with a single velocity subclass of atoms. Probe absorption line shapes clearly display the effects of pump-field strength (Rabi splittings), pump-field polarization (positions and number of Rabi-split resonance peaks), pump-field detuning (positions of resonance peaks), and optical pumping (relative strengths of the resonance peaks). The calculation is carried out with the use of an irreducible tensor basis for the atomic density matrix although a standard ($m$-basis) calculation is included in an appendix.

A. M. Akulshin, V. L. Velichanskiǐ, M. V. Krasheninnikov +4 more