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"Linear and nonlinear optical response of massless Dirac fermions"

Dr. Alexey Belyanin
Texas A&M University


Massless Dirac electrons in graphene and on the surface of 3D topological insulators such as Bi2Se3 demonstrate universal optical absorbance and strong optical nonlinearities. Although both systems constitute an isotropic medium for in-plane electron excitations, their second-order nonlinear susceptibility becomes non-zero when its spatial dispersion is taken into account. In this case the anisotropy is induced by in-plane wave vectors of obliquely incident or in-plane propagating electromagnetic waves. We discuss peculiarities of linear optical response and apparent violation of gauge invariance. We outline the main results of a quantum theory of the second-order nonlinear response and discuss its application to various nonlinear processes, such as second harmonic generation, parametric decay, and generation of entangled photon-plasmon states. If time permits, we will also discuss some of the exciting optical phenomena predicted for massless Dirac fermions in a strong magnetic field.

Wednesday, October 26, 2016
IQSE 578, 12:30 Noon
Mitchell Physics Building

Institute for Quantum Science and Engineering
Texas A&M University

(Sandwiches, salad, and soda to be served at 12:00 Noon)

Host: Dr. Alexey Akimov