Coherent backscattering of intense light by cold atoms with degenerate energy levels: Diagrammatic treatment

TL;DR

This paper extends the diagrammatic pump-probe method to analyze coherent backscattering of intense light by cold atoms with degenerate energy levels, revealing how degeneracy affects CBS enhancement at high saturation.

Contribution

It introduces a generalized diagrammatic approach for CBS in atoms with degenerate levels, providing insights into the impact of degeneracy on scattering signals under saturation.

Findings

Degeneracy causes a faster decrease in CBS enhancement at high saturation.

The approach characterizes double scattering signals in optically pumped atoms.

Internal degeneracy significantly influences CBS behavior in the saturation regime.

Abstract

We present a generalization of the diagrammatic pump-probe approach to coherent backscattering (CBS) of intense laser light for atoms with degenerate energy levels. We employ this approach for a characterization of the double scattering signal from optically pumped atoms with the transition $J_g\rightarrow J_e=J_g+1$ in the helicity preserving polarization channel. We show that, in the saturation regime, the internal degeneracy becomes manifest for atoms with $J_g\geq 1$, leading to a faster decrease of the CBS enhancement factor with increasing saturation parameter than in the non-degenerate case.