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

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.

22 pages, 9 Figures, submitted to PRB, Comments are welcomed

References in corpus (12)

• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• The electronic properties of bilayer graphene
• Universal dynamical conductance in graphite
• Optical and magneto-optical far-infrared properties of bilayer graphene
• Determination of the gate-tunable bandgap and tight-binding parameters in bilayer graphene using infrared spectroscopy
• Third order nonlinearity of graphene: effects of phenomenological relaxation and finite temperature
• Current injection by coherent one- and two-photon excitation in graphene and its bilayer
• Two-photon absorption in two-dimensional materials: The case of hexagonal boron nitride
• Higher-order contributions and non-perturbative effects in the non-degenerate nonlinear optical absorption of direct-gap semiconductors
• Im$\{{\chi }^{(3)}\}$ spectra of 110-cut GaAs, GaP, and Si near the two-photon absorption band edge
• Non-Degenerate Two-Photon Absorption in ZnSe: Experiment and Theory
• Nonlinear optical conductivity of a two-band crystal I