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arXiv · 2208.08143

Two-photon absorption in semiconductors: a multi-band length-gauge analysis

W. -R. Hannes·M. F. Ciappina
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Abstract

The simplest approach to deal with light excitations in direct-gap semiconductors is to model them as a two-band system: one conduction and one valence band. For such models, particularly simple analytical expressions are known to exist for the optical response such as multi-photon absorption coefficients. Here we show that generic multi-band models do not require much more complicated expressions. Our length-gauge analysis is based on the semiconductors Bloch equations in the absence of all scattering processes. In the evaluation, we focus on two-photon excitation by a pump-probe scheme with possibly non-degenerate and arbitrarily polarized configurations. The theory is validated by application to graphene and its bilayer, described by a tight-binding model, as well as bulk Zincblende semiconductors described by k.p theory.

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W. -R. Hannes, M. F. Ciappina. 2022-08-17. Two-photon absorption in semiconductors: a multi-band length-gauge analysis. https://doi.org/10.1103/physrevb.106.115204

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