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Showing posts with label nonlinear terahertz response. Show all posts
Showing posts with label nonlinear terahertz response. Show all posts
We consider the nonlinear terahertz response of n-doped monolayer graphene at room temperature using a microscopic theory of carrier dynamics. Our tight-binding model treats the carrier-field interaction in the length gauge, includes phonon as well as short-range neutral-impurity scattering, and fully accounts for the intrinsic nonlinear response of graphene near the Dirac point. Treating each interaction microscopically allows us to separate contributions from current clipping, phonon creation, and elastic impurity scattering. Although neutral impurity scattering and phonon scattering are both highly energy-dependent, we find that they impact conduction-band electron dynamics very differently, and that together they can help explain experimental results concerning field-dependent terahertz transmission through graphene.
The electron states as well as the nonlinear optical rectification and second and third harmonic generations are investigated in a GaAs-based V-groove quantum wire. The single band effective mass Schrödinger equation is solved using the finite element method. The nonlinear optical coefficients were calculated from expressions derived within the compact density matrix method. It is found that this kind of nanostructures can exhibit noticeable nonlinear responses in the domain of the terahertz when the V-groove is in the open-wide geometrical configuration.
