Generation of even and odd high harmonics in resonant metasurfaces using single and multiple ultra-intense laser pulses

TL;DR

This paper demonstrates a nanoscale gallium phosphide metasurface that efficiently generates even and odd high harmonics using ultra-intense mid-infrared laser pulses, enabling advanced control of light-matter interactions at the nanoscale.

Contribution

It introduces a resonant GaP metasurface platform for high harmonic generation, achieving high efficiency and broad photon energy coverage with minimal reabsorption.

Findings

Efficient generation of even and odd harmonics between 1.3 and 3 eV.

Single-shot measurements prevent material damage.

Facilitates control over perturbative and non-perturbative regimes.

Abstract

High harmonic generation (HHG) opens a window on the fundamental science of strong-field light-mater interaction and serves as a key building block for attosecond optics and metrology. Resonantly enhanced HHG from hot spots in nanostructures is an attractive route to overcoming the well-known limitations of gases and bulk solids. We demonstrate a nanoscale platform for highly efficient HHG driven by strong mid-infrared laser pulses: an ultra-thin resonant gallium phosphide (GaP) metasurface. The wide bandgap and the lack of inversion symmetry of the GaP crystal enable the generation of even and odd harmonics covering a wide range of photon energies between 1.3 and 3 eV with minimal reabsorption. The resonantly enhanced conversion efficiency facilitates single-shot measurements that avoid material damage and pave the way to controllable transition between perturbative and non-perturbative regimes of light-matter interactions at the nanoscale.