Unconventional double-bended saturation of optical transmission in graphene due to many-particle interactions

TL;DR

This study uncovers a novel double-bended saturation phenomenon in graphene's optical transmission, driven by complex many-particle interactions and phase-space filling, with distinct saturation fluences and physical origins.

Contribution

It provides the first combined theoretical and experimental analysis revealing an unconventional double-bended saturation behavior in graphene due to many-particle effects.

Findings

Identification of two separate saturation fluences with three orders of magnitude difference

Demonstration of the physical origin of each saturation behavior

Revealing the role of many-particle scattering and phase-space filling in saturation dynamics

Abstract

We present a joint theory-experiment study on the transmission/absorption saturation after ultrafast pulse excitation in graphene. We reveal an unconventional double-bended saturation behavior: Both bendings separately follow the standard saturation model exhibiting two saturation fluences, however, the corresponding fluences differ by three orders of magnitude and have different physical origin. Our results reveal that this new and unexpected behavior can be ascribed to an interplay between fluence- and time-dependent many-particle scattering processes and phase-space filling effects.