D. Mathura and F. A. Rajgara Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai 400 005, India Received 9 June 2010; accepted 30 June 2010; published online 9 August 2010
Intense, ultrashort pulses of 800 nm laser light 12 fs, 4 optical cycles of peak intensity 5 x10^14 W cm−2 have been used to irradiate gas-phase Xen clusters n=500–25 000
so as to induce multiple ionization and subsequent Coulomb explosion. Energy distributions of exploding ions are measured in the few-cycle domain that does not allow sufficient time for the cluster to undergo expansion due to Coulombic and hydrodynamic pressures. This results in overall dynamics that appear to be significantly different to those in the many-cycle regime. One manifestation is that the maximum ion energies are measured to be much lower than those obtained when longer pulses of the same intensity are used. Ion yields are cluster-size independent but polarization dependent in that they are significantly larger when the polarization is perpendicular to the detection axis than along it. This unexpected behavior is qualitatively rationalized in terms of a spatially anisotropic shielding effect induced by the electronic charge cloud within the cluster. © 2010 American Institute of Physics.
EFS Comments: This is in keeping with expectations and observed effects using switching technology to drive the LEEF cycle.
