Two-photon absorption in silicon using real density matrix approach

TL;DR

This paper introduces an analytical model based on the Real Density Matrix Approach to better understand two-photon absorption in silicon, providing insights into experimental data for indirect-gap semiconductors.

Contribution

It presents a novel analytical expression for two-photon absorption in silicon using the Real Density Matrix Approach, enhancing understanding of excitonic effects in indirect-gap materials.

Findings

Analytical expression for two-photon absorption coefficient dispersion

Explains experimental trends in silicon absorption data

Minimal fitting required for data explanation

Abstract

Two-photon absorption in indirect gap semiconductors is an frequently encountered, but not well-understood phenomenon. To address this, the Real Density Matrix Approach is applied to describe two-photon absorption in silicon through the excitonic response to the interacting fields. This approach produces an analytical expression for the dispersion of the two-photon absorption coefficient for indirect-gap materials, and can be used to explain trends in reported experimental data for bulk silicon both old and new with minimal fitting.