title: Giant Two-photon Absorption in Circular Graphene Quantum Dots in Infrared Region.
abstract: We investigate theoretically the two-photon absorption (TPA) for circular graphene quantum dots (GQDs) with the edge of armchair and zigzag on the basis of electronic energy states obtained by solving the Dirac-Weyl equation numerically under finite difference method. The expressions for TPA cross section are derived and the transition selection rules are obtained. Results reveal that the TPA is significantly greater in GQDs than conventional semiconductor QDs in infrared spectrum (2-6 um) with a resonant TPA cross section of up to 10(11 )GM. The TPA peaks are tuned by the GQDs' size, edge and electron relaxation rate.
authors.affiliation: School of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Feng
authors.affiliation: School of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, China.
authors.forename: Zhisong
authors.initials: Z
authors.lastname: Li
authors.affiliation: School of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: School of Physics and Electronic Information, Yunnan Normal University, Kunming 650500, China.
authors.forename: Yingkai
authors.initials: Y
authors.lastname: Liu