Adiabatic approach for high harmonic generation in solids induced by intense low-frequency pulses

TL;DR

This paper develops an analytical adiabatic model for high harmonic generation in solids under intense low-frequency laser pulses, explaining key features and the dominance of interband mechanisms.

Contribution

It introduces a nonperturbative adiabatic approach with closed-form formulas for electron states, current, and HHG spectra in solids with multiband structures.

Findings

Interband mechanism dominates HHG yield.

Analytic formulas accurately describe HHG spectra.

The theory explains key features of HHG in solids.

Abstract

An analytic description of high harmonic generation (HHG) in solids induced by intense low-frequency pulses is presented within an adiabatic approach, which treats laser-matter interactions nonperturbatively. We derive the analytical expression for the laser-dressed state of an electron in an arbitrary spatially periodic potential, taking into account multiband structure of the solid target. Closed-form formulas for electron current and HHG spectra are presented. Based on the developed theory, we provide an analytic explanation for key features of HHG yield and show that the interband mechanism of HHG prevails over the intraband one.