Abstract
In this experimental work we report our findings about a Ladder (
Ξ
) transition 5S
1∕2
→ 5P
3∕2
→ 5D
3∕2
of
85
Rb atoms under different laser power combinations. Based on the ratio of power levels of two individual lasers, which are used in counter-propagating configuration, the system exhibits double resonance optical pumping and Autler-Townes splitting. The excursion of the
Ξ
level coupling is studied alongwith photon counting of blue light originating from 5D
3∕2
→ 6P
3∕2
→ 5S
1∕2
non-degenerate decay. The blue photon statistics shows that emitted radiation are thermal. However the probability density of the integrated photon count vs. laser power exhibits a jump in intensity scale followed by a long tail, which resembles Lèvy type distribution. This may be considered as a signature when the level dressing changes in
Ξ
system as theoretically discussed earlier by Abi-Salloum [T.Y. Abi-Salloum, J. Mod. Opt.
57
, 1366 (2010); T.Y. Abi-Salloum, Phys. Rev. A
81
, 053836 (2010)].
Graphical abstract