The normal-incidence reflectivity of a plasma generated on a solid surface by a very intense laser field is studied. We demonstrate that the reflected field has the form of trains of subfemtosecond pulses under suitable conditions. Particle-in-cell computations are presented and compared with a naïve moving-mirror model. The physical origin of this behavior is discussed in terms of the relativistic motion of the electron plasma.
[Optical Society of America ]
Luis Plaja, Luis Roso, Kazimierz Rzazewski, and Maciej Lewenstein, "Generation of attosecond pulse trains during the reflection of a very intense laser on a solid surface," J. Opt. Soc. Am. B 15, 1904-1911 (1998)