Improved stabilization scheme for extreme ultraviolet quantum interference experiments

TL;DR

This paper presents an enhanced phase stabilization scheme for XUV interferometric experiments, improving signal stability by incorporating stabilization of the XUV beam path in free electron laser setups.

Contribution

The authors extend existing stabilization methods by including XUV beam path stabilization, leading to better phase stability in extreme ultraviolet interferometry.

Findings

Significant signal improvement with the new stabilization scheme

Effective stabilization of both seed laser and XUV beam paths

Enhanced phase stability in XUV interferometric experiments

Abstract

Interferometric pump-probe experiments in the extreme ultraviolet (XUV) domain are experimentally very challenging due to the high phase stability required between the XUV pulses. Recently, an efficient phase stabilization scheme was introduced for seeded XUV free electron lasers (FELs) combining shot-to-shot phase modulation with lock-in detection. This method stabilized the seed laser beampath on the fundamental ultraviolet wavelength to a high degree. Here, we extend this scheme including the stabilization of the XUV beampath, incorporating phase fluctuations from the FEL high gain harmonic generation process. Our analysis reveals a clear signal improvement with the new method compared to the previous stabilization scheme.