41 research outputs found
Alignment-to-orientation conversion in the ground state of atomic Cs with linearly polarized laser excitation
In this study we explored the angular momentum alignment-to-orientation
conversion occurring in various alkali metals -- K, Rb, Cs. We used a
theoretical model that is based on Optical Bloch equations and uses the density
matrix formalism. Our model includes the interaction of all neighboring
hyperfine levels, the mixing of magnetic sublevels in an external magnetic
field, the coherence properties of the exciting laser radiation, and the
Doppler effect. Additionally we simulated signals where the ground- or the
excited-state coherent processes were switched off allowing us to determine the
origins of obtained signals. We also performed experiments on Cs atoms with two
laser beams: linearly polarised Cs D1 pump and circularly polarized Cs D2
probe. We used the pump beam to create angular momentum alignment in the ground
state and observed the transmission signal of the probe beam as we changed the
magnetic field. Full analysis of the experimentally obtained transmission
signal from a single circularly polarized probe laser component is provided.Comment: arXiv admin note: text overlap with arXiv:2006.1501
Angular momentum spatial distribution symmetry breaking in Rb by an external magnetic field
Excited state angular momentum alignment -- orientation conversion for atoms
with hyperfine structure in presence of an external magnetic field is
investigated. Transversal orientation in these conditions is reported for the
first time. This phenomenon occurs under Paschen Back conditions at
intermediate magnetic field strength. Weak radiation from a linearly polarized
diode laser is used to excite Rb atoms in a cell. The laser beam is polarized
at an angle of pi/4 with respect to the external magnetic field direction.
Ground state hyperfine levels of the 5S_1/2 state are resolved using
laser-induced fluorescence spectroscopy under conditions for which all excited
5P_3/2 state hyperfine components are excited simultaneously. Circularly
polarized fluorescence is observed to be emitted in the direction perpendicular
to both to the direction of the magnetic field B and direction of the light
polarization E. The obtained circularity is shown to be in quantitative
agreement with theoretical predictions.Comment: Accepted for publication in Phys. Rev.