Anomalous behavior of the saturated absorption resonance line shape on the $1\phantom{\rule{0.2em}{0ex}}{s}_{5}\ensuremath{-}2\phantom{\rule{0.2em}{0ex}}{p}_{8}(J=2\ensuremath{-}J=2)$ transition in the Ne atom is experimentally observed. The shape of the saturation resonance on transitions with degenerate excited states of atoms is numerically analyzed. The reasons and conditions for the anomalous behavior of the resonance line shape and the formation of its doublet spectral structure are established. The influence of the resonant light pressure force on the amplitude and the frequency properties of the saturated resonance is investigated. It is shown, that the asymmetry of the doublet splitting of the resonance is caused by the effect of resonant light pressure.
We report on the observation of a light-pressure-induced asymmetry of the well-known absorption dip occurring in optical saturation spectroscopy. This asymmetry is due to the small modification of the atomic velocity distribution that is caused by the spontaneous scattering force of the saturating light field. Our measurements were performed on the \ensuremath{\lambda}=555.65 nm
1S0${\mathrm{\ensuremath{-}}}^{3}$
P1 transition in atomic ytterbium vapor by the use of a frequency-modulated test field propagating collinearly with the scattering field. The experimental results clearly confirm theoretical predictions and demonstrate the significance of the phenomenon for high-resolution laser spectroscopy.
Anomalous behavior of the shape of saturated absorption resonance on the transition 1 s 5 → 2 p 8 ( J =2→ J =2) in the Ne atom is experimentally observed. The shape of the saturation resonance on transitions with degenerate excited states of atoms is analyzed numerically and the reasons for the anomalous behavior of the resonance shape and the formation of its doublet spectral structure are established. The effect of the resonance light pressure on the amplitude and frequency properties of resonance is investigated. It is shown that the asymmetry of the doublet splitting of the resonance is associated with the effect of resonance light pressure.