Optimal light storage in atomic vapor

TL;DR

This paper investigates methods to optimize light storage efficiency in warm Rb vapor using electromagnetically induced transparency, comparing two protocols and analyzing their effectiveness across different optical depths.

Contribution

It introduces and compares two optimization protocols for light storage in atomic vapor, demonstrating their consistency and effectiveness in maximizing efficiency.

Findings

Protocols achieve maximum efficiency at moderate optical depths

Efficiency drops below predictions at high optical depths

Identifies factors reducing memory efficiency at high optical depths

Abstract

We study procedures for the optimization of efficiency of light storage and retrieval based on the dynamic form of electromagnetically induced transparency (EIT) in warm Rb vapor. We present a detailed analysis of two recently demonstrated optimization protocols: a time-reversal-based iteration procedure, which finds the optimal input signal pulse shape for any given control field, and a procedure based on the calculation of an optimal control field for any given signal pulse shape. We verify that the two procedures are consistent with each other, and that they both independently achieve the maximum memory efficiency for any given optical depth. We observe good agreement with theoretical predictions for moderate optical depths (<25), while at higher optical depths the experimental efficiency falls below the theoretically predicted values. We identify possible effects responsible for this reduction in memory efficiency.