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arXiv · 1812.11306

Doping Induced Second Harmonic Generation in Centrosymmetric Graphene from Quadrupole Response

Yu Zhang·Di Huang·Yuwei Shan·Tao Jiang·Zhihong Zhang·Kaihui Liu·Lei Shi·Jinluo Cheng·John E. Sipe·Wei-Tao Liu·Shiwei Wu
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Abstract

For centrosymmetric materials such as monolayer graphene, no optical second harmonic generation (SHG) is generally expected because it is forbidden under the electric-dipole approximation. Yet we observed a strong, doping induced SHG from graphene, with its highest strength comparable to the electric-dipole allowed SHG in non-centrosymmetric 2D materials. This novel SHG has the nature of an electric-quadrupole response, arising from the effective breaking of inversion symmetry by optical dressing with an in-plane photon wave vector. More remarkably, the SHG is widely tuned by carrier doping or chemical potential, being sharply enhanced at Fermi edge resonances, but vanishing at the charge neutral point that manifests the electron-hole symmetry of massless Dirac Fermions. The striking behavior in graphene, which should also arise in graphene-like Dirac materials, expands the scope of nonlinear optics, and holds the promise of novel optoelectronic and photonic applications.

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Yu Zhang, Di Huang, Yuwei Shan, Tao Jiang, Zhihong Zhang, Kaihui Liu, Lei Shi, Jinluo Cheng, John E. Sipe, Wei-Tao Liu, Shiwei Wu. 2018-12-29. Doping Induced Second Harmonic Generation in Centrosymmetric Graphene from Quadrupole Response. https://doi.org/10.1103/physrevlett.122.047401

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