Complete characterization of a bright coherent table-top soft x-ray source up to the keV regime

• Unité de recherche: COST
• Numéro de projet: C13.0116
• Titre du projet anglais: Complete characterization of a bright coherent table-top soft x-ray source up to the keV regime

Mots-clé (Anglais)

high-order harmonic generation; wavefront measurements; soft x-ray laser keV photon range; absolute phase stable pulses; attosecond pulses; FEL seeding

Programme de recherche (Anglais)

COST-Action MP1203 - Advanced X-ray spatial and temporal metrology

Description succincte (Anglais)

Table-top and bright soft x-ray sources are excellently suited for time-resolved investigations down to the attosecond regime at high repetition rate. Conventional table-top sources are based on high-order harmonic generation in a rare gas driven by an intense near-IR Ti:sapphire laser. While this scheme offers short pulses (70 as) there are severe limitations in photon fluence and maximum achievable photon energies (<100 eV) which are cumbersome for many applications. Very recent investigations have shown a promising route towards overcoming the cut-off limitations by generating the harmonics with a mid-infrared (mIR) laser. Following those lines I want to explore different techniques to extend the maximum photon energies up to the keV range while enhancing the photon flux beyond state of the art. Such investigations are timely since a powerful table-top keV source delivering sub-femtosecond pulses opens new opportunities, such as time-resolved imaging applications of magnetic domains or seeding of a free electron laser at significantly shorter wavelength than state of the art. In order to enhance the harmonic fluence different approaches will be considered, such as mIR-driven HHG in ions. On the other hand the potential of optimizing the temporal shape of the driving electric field shall be explored for HHG by use of few-cycle pulses or by mixing different mid-IR frequencies. For those studies a carrier-envelope phase stable laser system is being developed.

Autres indications (Anglais)

Full name of research-institution/enterprise: Paul Scherrer Institute (PSI) / EPF Lausanne OVGA/324

Partenaires et organisations internationales (Anglais)

AT; HR; CZ; DK; EE; FI; FR; DE; EL; HU; IE; IT; PL; PT; RO: RS; SK; SI; ES; SE; TR; UK; US; TN

Résumé des résultats (Abstract) (Anglais)

The development of powerful, table-top soft x-ray lasers towards shorter wavelengths than what is delivered from state of the art technology is a very active field of research due to numerous scientific applications. Conventional table-top sources are based on high-order harmonic generation (HHG) in a rare gas driven by an intense near-infrared Ti:sapphire laser. While this scheme offers short pulses in the attosecond domain there are severe limitations in photon fluence and maximum achievable photon energies (<100 eV). One of the main objectives of our group is to overcome the source limitations in view of the maximum flux and photon energy by generating HHG radiation with an advanced mid-infrared laser source. The powerful mid-infrared laser at hand delivers intense mid-infrared laser pulses of several milli-Joules within only a few optical cycles. Our laser source is ideally suited for extending the cut-off photon energy produced by HHG towards the keV range. Our current activities aim at improving the conversion efficiency in order to realize a coherent x-ray source which is powerful enough for real-world applications. Furthermore we actively work on advanced metrology for characterizing the x-ray laser radiation in the range of 100-1000 eV. Our activities include the exploration of a novel temporal pulse characterization technique based on a THz streaking camera and a wavefront sensor.

Références bases de données (Anglais)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C13.0116