Spatial polarization gating of high-harmonic generation in solids

TL;DR

This paper introduces spatial polarization gating, a technique that uses a spatially varying laser ellipticity to enhance the spatial resolution of high-harmonic generation in solids, enabling imaging beyond the diffraction limit.

Contribution

The paper presents a novel spatial polarization gating method that improves the spatial resolution of high-harmonic generation in solids and explores its potential for super-resolution imaging.

Findings

Experimental and numerical validation of the method

Suppression of high harmonics in elliptical fields

Potential application to nonlinear structured illumination microscopy

Abstract

High-harmonic generation from solids can be utilized as probe of ultrafast dynamics, but thus far only over extended sample areas, since its spatial resolution is diffraction-limited. Here we propose spatial polarization gating, that is using a spatially varying ellipticity of a driving laser pulse to reduce the spatial profile of high-harmonic emission below the diffraction limit and hence increase spatial resolution. We show experimentally and by numerical simulations that our method is generally applicable as suppressing high harmonics in elliptical fields is a common response in all solids. We also briefly explore the possibility of applying this technique to widefield imaging, specifically to nonlinear structured illumination microscopy. Our findings indicate that spatial polarization gating can enable all-optical femto-to-attosecond label-free imaging beyond the Abbe limit.