Abstract

Judiciously designed two-dimensional THz metamaterials consisting of resonant metallic structures embedded in a dielectric environment locally enhance the electromagnetic field of an incident THz pulse to values sufficiently high to cause nonlinear responses of the environment. In semiconductors, the response is attributed to nonlinear transport phenomena via intervalley scattering, impact ionization, or interband tunneling and can affect the resonant behavior of the metallic structure, which results, for instance, in mode switching. So far, several studies have demonstrated nonlinear mode switching [1,2], but even though the physics underlying the field-induced semiconductor response was tentatively assigned to specific carrier generation mechanisms, a detailed picture and especially the relevant time scales of mode switching are still under debate.

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