Dynamics of the critical surface in high-intensity laser-solid interactions: modulation of the XUV harmonic spectra.
The generation of harmonics from the interaction of an intense (I>or=10(18) W cm(-2)) laser with a solid surface is investigated. Modulation of the harmonic emission spectrum with a periodicity of 2 to 4 harmonics is observed at higher laser intensities. A similar modulation is predicted by a particle-in-cell simulation. The modulation is shown to be caused by the higher modes of oscillation of the critical surface during the interaction. As a result, the dynamics of the critical surface can be inferred from the shape of the harmonic spectrum.
Watts
I
I
The Blackett Laboratory, Imperial College of Science, Technology and Medicine, Prince Consort Road, London SW7 2BZ, United Kingdom.
Zepf
M
M
Clark
E L
EL
Tatarakis
M
M
Krushelnick
K
K
Dangor
A E
AE
Allott
R M
RM
Clarke
R J
RJ
Neely
D
D
Norreys
P A
PA