Floquet-Volkov interference in a semiconductor

TL;DR

This study demonstrates the experimental observation of Floquet-Volkov interference in black phosphorus, revealing asymmetric spectral modulation controlled by light polarization, which advances understanding of light-matter interactions at ultrafast timescales.

Contribution

It provides the first experimental evidence of Floquet-Volkov interference in a semiconductor, showing controllable asymmetric spectral modulation via pump polarization.

Findings

Asymmetric spectral weight modulation observed in Floquet-Volkov states

Control of interference asymmetry through pump polarization rotation

Insights into quantum interference of light-field dressed electronic states

Abstract

Intense light-field can dress both Bloch electrons inside crystals and photo-emitted free electrons in the vacuum, dubbed as Floquet and Volkov states respectively. These quantum states can further interfere coherently, modulating light-field dressed states. Here, we report experimental evidence of the Floquet-Volkov interference in a semiconductor - black phosphorus. A highly asymmetric modulation of the spectral weight is observed for the Floquet-Volkov states, and such asymmetry can be further controlled by rotating the pump polarization. Our work reveals the quantum interference between different light-field dressed electronic states, providing insights for material engineering on the ultrafast timescale.