Induced transparency in the XUV: a pump-probe test of laser-cluster interactions

An experiment is proposed to distinguish between different laser-cluster atomistic models and their predictions. The induced transparency of rare-gas clusters, post-interaction with an extreme ultraviolet (XUV) pump-pulse, is predicted by using an atomistic hybrid quantum-classical molecular dynamics model. We find there is an intensity range for which an XUV probe-pulse has no lasting effect on the average charge state of a cluster after being saturated by an XUV pump-pulse: the cluster is transparent to the probe-pulse. Multiple complete experimental signals are calculated which include the effect of the pulse's spatial distribution as well as the cluster size distribution. The calculated experimental signals and trends are also accomplished with the addition of an ionization potential lowering model that results in effectively removing the induced transparency effect. Thus, the proposed experiment is expected to either find the new phenomenon of induced transparency in clusters or give strong evidence for the existence of the enhanced ionization phenomenon, ionization potential lowering, in nanoplasmas.