Post-compression of high energy terawatt-level femtosecond pulses and application to high order harmonic generation

TL;DR

This paper demonstrates a method for post-compressing high energy femtosecond pulses using optical-field ionization in helium gas, achieving 10 fs pulses at TW energy levels suitable for high harmonic generation.

Contribution

It introduces a novel post-compression technique for high energy pulses using guided helium gas ionization, enabling stable 10 fs pulses at TW levels for high harmonic generation.

Findings

Achieved 10 fs pulse duration at TW energy levels.

Controlled spectral broadening via input energy and gas pressure.

Generated structured continuous XUV spectra in high harmonic generation.

Abstract

We perform a post-compression of high energy pulses by using optical-field ionization of low pressure helium gas in a guided geometry. We apply this approach to a TW chirped-pulse-amplification based Ti:Sapphire laser chain and show that spectral broadening can be controlled both with the input pulse energy and gas pressure. Under optimized conditions, we generate 10 fs pulses at TW level directly under vacuum and demonstrate a high stability of the post compressed pulse duration. These high energy post-compressed pulses are thereafter used to perform high harmonic generation in a loose focusing geometry. The XUV beam is characterized both spatially and spectrally on a single shot basis and structured continuous XUV spectra are observed.