Extremely Nonlinear Optics Using Shaped Pulses Spectrally Broadened in an Argon- or Sulfur Hexafluoride-Filled Hollow-Core Fiber

Andreas Hoffmann,Michael Zürch,Christian Spielmann

doi:10.3390/app5041310

Andreas Hoffmann, Michael Zürch + Show 1 more

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https://doi.org/10.3390/app5041310

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Abstract

In this contribution we present a comparison of the performance of spectrally broadened ultrashort pulses using a hollow-core fiber either filled with argon or sulfur hexafluoride (SF6) for demanding pulse-shaping experiments. The benefits of both gases for pulse-shaping are studied in the highly nonlinear process of high-harmonic generation. In this setup, temporally shaping the driving laser pulse leads to spectrally shaping of the output extreme ultraviolet (XUV) spectrum, where total yield and spectral selectivity in the XUV are the targets of the optimization approach. The effect of using sulfur hexafluoride for pulse-shaping the XUV yield can be doubled compared to pulse compression and pulse-shaping using argon and the spectral range for selective optimization of a single harmonic can be extended. The obtained results are of interest for extending the range of ultrafast science applications drawing on tailored XUV fields.

Highlights

High-harmonic generation (HHG) has been extensively studied to generate extreme ultraviolet (XUV) and soft-X-ray frequencies supporting the generation of pulses down in the attosecond range [1]
The high average power of optimized high-harmonic generation (HHG) sources allow coherent diffraction imaging [6] which paves the way for using HHG sources for biological and medical applications [7], especially bearing in mind the ongoing effort to push HHG into the water window [8,9]
The optimization for the total XUV yield was performed for four different gas pressures in the HHG-hollow-core fiber (HCF) and the results are summarized in Figure 6, where the integrated signal between 23 nm and 43 nm was used as fitness parameter

Summary

Introduction

High-harmonic generation (HHG) has been extensively studied to generate extreme ultraviolet (XUV) and soft-X-ray frequencies supporting the generation of pulses down in the attosecond range [1]. The spectral, spatial and temporal properties of the HHG radiation make it a versatile tool in atomic and molecular spectroscopy [2]. To realize a matched source for the envisaged spectroscopic applications, much work has been done in controlling the shape of the HHG spectrum by either modifying the driving laser field [3,4] or using multicolor fields [5]. Using shaped driving laser fields is a promising way to increase the HHG conversion efficiency. Two major scaling laws render HHG difficult for practical applications, namely:

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