Spectral dependence of diffuse light dynamics in ultracold atomic 85Rb

TL;DR

This study combines experiments and simulations to analyze how the spectral properties influence the decay dynamics of multiply scattered light in ultracold 85Rb atoms, revealing near resonance effects and Fourier component interactions.

Contribution

It provides a detailed spectral analysis of diffuse light dynamics in ultracold atoms, integrating experimental data with Monte Carlo simulations to interpret scattering behavior.

Findings

Decay is nearly exponential at long times regardless of detuning.

Near resonance scattering involves Fourier components of the pulse.

Beating observed between Rayleigh scattered light and pulse Fourier components.

Abstract

We report a combined experimental and theoretical simulation of multiply scattered light dynamics in an ultracold gas of 85Rb atoms. Measurements of the spectral dependence of the time-decay of the scattered light intensity, following pulsed excitation with near resonance radiation, reveals that the decay for long times is nearly exponential, with a decay constant that is largely independent of detuning from resonance. Monte Carlo simulations of the multiple scattering process show that, for large detunings, near resonance scattering of Fourier components of the excitation pulse plays a significant role in the effect. This interpretation is supported by the observations, and successful modelling, of beating between Rayleigh scattered light at the excitation carrier frequency with the Fourier components of the excitation pulse that overlap significantly with the atomic resonance.