Measurement and simulation of laser-induced fluorescence from non-equilibrium ultracold neutral plasmas

TL;DR

This study combines measurements and simulations of laser-induced fluorescence to investigate early-time ion dynamics in ultracold neutral plasmas, revealing insights into non-equilibrium behavior and coherent oscillations.

Contribution

It introduces a detailed simulation framework for laser-induced fluorescence in ultracold plasmas and demonstrates its effectiveness in probing early-time ion dynamics.

Findings

Observation of initial Bloch vector rotation

Detection of disorder-induced heating

Identification of coherent ion velocity oscillations

Abstract

We report new measurements and simulations of laser-induced fluorescence in ultracold neutral plasmas. We focus on the earliest times, when the plasma equilibrium is evolving and before the plasma expands. In the simulation, the ions interact via the Yukawa potential in a small cell with wrapped boundary conditions. We solve the optical Bloch equation for each ion in the simulation as a function of time. Both the simulation and experiment show the initial Bloch vector rotation, disorder-induced heating, and coherent oscillation of the rms ion velocity. Detailed modeling of the fluorescence signal makes it possible to use fluorescence spectroscopy to probe ion dynamics in ultracold and strongly coupled plasmas.