High brightness keV harmonics from relativistically oscillating plasma surfaces
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: email@example.com
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°).
© EDP Sciences, Springer-Verlag, 2009