Cooperative Emission of a Coherent Superflash of Light

TL;DR

This paper studies the transient coherent transmission of light in a cold strontium gas, revealing a superbright flash caused by cooperative atomic emission, and explains the underlying physical mechanisms.

Contribution

It demonstrates the observation of a superflash phenomenon and provides a simplified physical explanation of cooperative atomic emission in transient conditions.

Findings

Peak intensity exceeds three times the incident light.

Cooperative forward emission is the key mechanism.

Fast transient control clarifies physical processes.

Abstract

We investigate the transient coherent transmission of light through an optically thick cold stron-tium gas. We observe a coherent superflash just after an abrupt probe extinction, with peak intensity more than three times the incident one. We show that this coherent superflash is a direct signature of the cooperative forward emission of the atoms. By engineering fast transient phenomena on the incident field, we give a clear and simple picture of the physical mechanisms at play.