Gain characteristics of THz surface plasmons in electrically pumped monolayer graphene

¹ Qingdao Key Laboratory of Terahertz Technology, College of Electronic Communication and Physics,Shandong University of Science and Technology, Qingdao 266590, P.R. China
² College of Electronic Information Engineering, Tianjin University of Technology, Tianjin 300384, P.R. China

^a e-mail: ypzhang1976@126.com

Received: 30 October 2014
Revised: 9 December 2014
Accepted: 22 December 2014
Published online: 27 January 2015

Abstract

Considering the electrically pumped monolayer graphene structures with split gates, we calculated propagation index and the imaginary part of ac conductivity, and numerically simulated the surface plasmons (SPs) frequency dependence on the absorption coefficient and the real part of the propagation index. From the simulations, the SPs gain is larger at low temperature, small gate voltage, long momentum relaxation time and high bias voltage. We compared SPs absorption coefficient and the real part of the propagation index between electrically pumped and optically pumped monolayer graphene. SPs stimulated in electrically pumped monolayer graphene have a large gain with higher bias voltage.