Enhanced harmonic generation in relativistic laser plasma interaction
  We report the enhancement of individual harmonics generated at a relativistic ultra-steep plasma vacuum interface. Simulations show the harmonic emission to be due to the coupled action of two high velocity oscillations -- at the fundamental $\omega_L$ and at the plasma frequency $\omega_P$ of the bulk plasma. The synthesis of the enhanced harmonics can be described by the reflection of the incident laser pulse at a relativistic mirror oscillating at $\omega_L$ and $\omega_P$. 
C. R\"odel, E. Eckner, J. Bierbach, M. Yeung, B. Dromey, T. Hahn, S.   Fuchs, A. Galestian, M. Wuensche, S. Kuschel, D. Hemm...
physics.plasm-ph physics.optics