High-harmonic spectroscopy of strongly bound excitons in solids

TL;DR

This paper investigates how high-harmonic spectroscopy can be used to detect and analyze excitons in solids, revealing their signatures, recombination, and energy shifts through ab initio simulations and analytical models.

Contribution

It introduces a novel approach to identify and study excitons in solids using high-harmonic spectra, combining simulations and analytical insights.

Findings

Exciton populations produce distinct signatures in high-harmonic spectra.

Exciton recombination signatures can be detected in the spectra.

Shifts in exciton energy levels are imprinted in harmonic signals.

Abstract

We explore the nonlinear response of ultrafast strong-field driven excitons in a one-dimensional solid with ab initio simulations. We demonstrate from our simulations and analytical model that a finite population of excitons imprints unique signatures to the high-harmonic spectra of materials. We show the exciton population can be retrieved from the spectra. We further demonstrate signatures of exciton recombination and that a shift of the exciton level is imprinted into the harmonic signal. The results open the door to high-harmonic spectroscopy of excitons in condensed-matter systems.