Terahertz photon mixing effect in gapped graphene

Authors

Yee Sin Ang, University of WollongongFollow
Shareef Sultan, University of Wollongong
Asya Tawfiq, University of WollongongFollow
Juncheng Cao, Shanghai Institute of Microsystem and Information Technology
Chao Zhang, University of WollongongFollow

RIS ID

61916

Publication Details

Ang, Y. Sin., Sultan, S., Tawfiq, A., Cao, J. & Zhang, C. (2012). Terahertz photon mixing effect in gapped graphene. Journal of Infrared, Millimeter and Terahertz Waves, 33 (8), 816-824.

Abstract

We theoretically calculate the terahertz waves mixing effect in doped graphene with a finite bandgap. The temperature dependence of the nonlinear intraband optical response at bandgap opening of few tens of meVare investigated. When the external electric field is weak, a moderate level of bandgap opening is found to slightly enhance the nonlinear optical response. The optical response is however significantly altered under strong-field condition. The strong-field nonlinear optical conductivity exhibits two distinct response ‘hot spot’: (i) low temperature with large bandgap and (ii) high temperature with small bandgap. The electric field required for the nonlinear response to dominate over the linear response is typically in the order of 10⁴ V/cm. This value increases rapidly by a factor of 10 in large bandgap and high temperature regimes. Our results suggest that photon mixing effect in gapped graphene is strongly gapped dependent and hence the bandgap opening has to be carefully engineered in order to optimize the photon mixing effect in gapped graphene.