Giant Two-photon Absorption in Circular Graphene Quantum Dots in Infrared Region

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 s...

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Bibliographic Details
Main Authors: Feng, Xiaobo, Li, Zhisong, Li, Xin, Liu, Yingkai
Format: Online
Language:English
Published: Nature Publishing Group 2016
Online Access:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5024087/
Description
Summary: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 1011 GM. The TPA peaks are tuned by the GQDs’ size, edge and electron relaxation rate.