High harmonic generation with circularly polarized fields in solid: a quantum trajectory perspective

TL;DR

This paper explores high harmonic generation in solids driven by elliptically polarized laser fields, introducing a reciprocal-space-trajectory method to explain the phenomena and providing new insights into the underlying physics.

Contribution

It develops the reciprocal-space-trajectory (RST) method to quantitatively analyze HHG in solids and elucidate the effects of laser ellipticity on the harmonic spectra.

Findings

Two-plateau structure in HHG spectra depends on laser ellipticity.

First plateau decreases while second plateau increases with ellipticity.

RST method accurately reproduces and explains HHG phenomena.

Abstract

We investigate the high harmonic generation (HHG) in solids driven by laser fields with different ellipticities. The HHG spectra show a two-plateau structure within the energy gap between the valence band and the first conduction band. These two plateaus depend distinctly on the laser ellipticity. The first plateau is decreased while the second plateau is enhanced with increasing the laser ellipticity. To understand these phenomena, we develop an intuitive Reciprocal-Space- Trajectory (RST) method, with which HHG in solids is explained by a trajectory-ensemble from different initial states and different ionization times in the reciprocal space. In the framework of RST, we can not only quantitatively reproduce the HHG spectra, but also well understand the underlying physics of these phenomena, providing a deep insight into the mechanism of HHG in solids.