13-14 June 2013, Annual meeting NAUUL - 'Operation of PW laser facilities', Jena, Germany

Venue: Dornburg Castle, Jena, Germany

Topics:
• measurement of the intensity at >10^21W/cm2
• detection & correction of laser pulse aberrations
• Detection & shielding of secondary radiation
• Novel targets & target manipulation
• Issues of current laser designs

The 2013 annual meeting of the Networking Activity of Ultra-intense Ultrashort Lasers (NAUUL) was held at the Dornburg Castle, near Jena (Germany), the 13th and 14th of June 2013. It was co-organized by Prof. Gerhard Paulus (Helmholtz Institute – Jena, Germany), Prof. Philippe Martin (CEA – Saclay, France), and Dr. Ricardo Torres (CLPU – Salamanca, Spain). The meeting coincided with the 2nd Workshop on Operation of PW-class Lasers, the first of which took place in 2012 in Paris.

The workshop was devoted to PW-class lasers and addressed the most pressing issues concerning the day-to-day operation of high-intensity lasers, including topics like pulse characterisation and control, targetry, detection of secondary radiation, etc. It attracted some of the most recognised experts from Europe on each topic. One of these problems is how to measure accurately the properties of the laser pulses at such high powers. In particular, some novel methods for measuring ultra-high intensities were proposed, based on the momentum distribution of laser-produced ions (Gerhard Paulus), laser-induced Zeeman effect (Evgeny Stambulchik – Weizmann Institute of Science, Israel), and non-linear Thomson scattering (Antonino Di Piazza – Max Planck Institute for Nuclear Physics, Heidelberg, Germany). The enhancement of the pulse contrast and its measurement is another important issue, which becomes more critical as the intensities get higher. Also critical is the current impossibility to measure the pulse contrast in a single shot. Methods to reduce the pre/post-pulses and the experience with the Polaris laser in Jena (Malte Kaluza – Helmholtz Institute – Jena, Germany) and the Vulcan laser in the UK (Alexis Boyle – CLF-RAL, UK) were presented.

Apart from the issues concerning the lasers themselves, the utilization of these systems in the laboratory poses many technical difficulties. The protection of the electronic equipment against the electromagnetic pulse generated by the laser shot was addressed by Eyal Kroupp (Weizmann Institute of Science, Israel). The production of microtargets for laser-plasma interaction is becoming very challenging due to the ever more sophisticated target designs demanded by the experimenters, and the need to deliver targets at the high repetition rates of current state-of-the-art high-intensity lasers. The most advanced techniques for target fabrication and characterization were presented by Chris Spindloe (CLF-RAL, UK). The increasing repetition rate of forthcoming laser systems also pose a challenge to the detectors of the particles originated in the laser-target interaction. Josefine Metzkes (Helmholtz-Zentrum Dresden-Rossendorf, Germany) showed her achievements in the development of online proton detectors based on scintillators.

Finally, representatives from two branches of the Extreme Light Infrastructure (ELI) - ELI-ALPS (Attosecond Light Pulse Source, Mikhail Kalashnikov) and ELI-NP (Nuclear Physics, Traian Dascalu) - presented an update of the progress on both projects, and the commercial companies Amplitude Technologies (Gilles Riboulet) and Thales Optronique (Denis Levaillant) provided the manufacturers' point of view into the problems of operating PW-class lasers.

Ricardo Torres

Organizers:
Philippe Martin (CEA, Saclay, France)
Ricardo Torres (CLPU, Salamanca, Spain)
Gerhard G. Paulus (University & HI Jena, Germany)