Phase cycling of extreme ultraviolet pulse sequences generated in rare gases

TL;DR

This paper introduces a new experimental method for controlling and phase cycling extreme-ultraviolet pulse sequences generated in rare gases, enabling coherent nonlinear spectroscopy in the XUV regime.

Contribution

The work presents a novel approach for timing control and phase cycling of XUV pulses, overcoming previous experimental challenges in this wavelength range.

Findings

Successful generation of narrow-bandwidth harmonics (~14 eV) in argon and krypton.

High spectral resolution characterization of the generated harmonics.

Achieved high phase stability and pathway-selective detection for nonlinear signals.

Abstract

The development of schemes for coherent nonlinear time-domain spectroscopy in the extreme-ultraviolet regime (XUV) has so far been impeded by experimental difficulties that arise at these short wavelengths. In this work we present a novel experimental approach, which facilitates the timing control and phase cycling of XUV pulse sequences produced by harmonic generation in rare gases. The method is demonstrated for the generation and high spectral resolution characterization of narrow-bandwidth harmonics ($\approx14\,$eV) in argon and krypton. Our technique simultaneously provides high phase stability and a pathway-selective detection scheme for nonlinear signals - both necessary prerequisites for all types of coherent nonlinear spectroscopy.