Eur. Phys. J. Special Topics 175, 57-60 (2009)
https://doi.org/10.1140/epjst/e2009-01117-4

High brightness keV harmonics from relativistically oscillating plasma surfaces

¹ Department of Physics and Astronomy, Queen's University, Belfast, BT7 1NN, UK
² Blackett Laboratory, Imperial College, London, SW7 2BZ, UK
³ SUPA, Department of Physics, University of Strathclyde, Glasgow, G4 0NG, UK
⁴ Central Laser Facility, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK

Corresponding author: b.dromey@qub.ac.uk

Abstract

X-ray harmonic radiation extending to 3.3 Å, 3.8 keV from Petawatt class laser-solid interactions is presented. The harmonic spectra display a relativistic limit scaling up to ~3000th order, above which an intensity dependent scaling roll-over is observed. Highly directional beamed emission for harmonic photon energy hν > 1 keV is found to be into a cone angle < 4°, significantly less than that of the incident laser cone (20°).