Microscopic mechanism for transient population inversion and optical gain in graphene

Based on microscopic calculations, we predict a transient femtosecond population inversion in graphene suggesting graphene as a new active gain material covering a broad frequency range. In this paper, we microscopically shed light on the underlying elementary many-particle processes: Transient gain...

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Bibliographic Details
Published in:	Physical review. B, Condensed matter and materials physics Vol. 87; no. 16
Main Authors:	Winzer, Torben, Malić, Ermin, Knorr, Andreas
Format:	Journal Article
Language:	English
Published:	08-04-2013
Subjects:	Augers Condensed matter Femtosecond Gain Graphene Mathematical analysis Optical pumping Population inversion
Online Access:	Get full text
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Summary:	Based on microscopic calculations, we predict a transient femtosecond population inversion in graphene suggesting graphene as a new active gain material covering a broad frequency range. In this paper, we microscopically shed light on the underlying elementary many-particle processes: Transient gain and population inversion occur due to an interplay of strong optical pumping and carrier cooling that fills states close to the Dirac point giving rise to a relaxation bottleneck. The subsequent femtosecond decay of the optical gain is mainly driven by Coulomb-induced Auger recombination. Our findings are in excellent agreement with recent experimental data.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1098-0121 1550-235X
DOI:	10.1103/PhysRevB.87.165413