Polarization Dependence of Bulk Ion Acceleration from Ultrathin Foils Irradiated by High-Intensity Ultrashort Laser Pulses

'The acceleration of ions from ultrathin (10-100 nm) carbon foils has been investigated using intense (similar to 6 x 10(20) W cm(-2)) ultrashort (45 fs) laser pulses, highlighting a strong dependence of the ion beam parameters on the laser polarization, with circularly polarized (CP) pulses producing the highest energies for both protons and carbons (25 - 30 MeV/nucleon); in particular, carbon ion energies obtained employing CP pulses were significantly higher (similar to 2.5 times) than for irradiations employing linearly polarized pulses. Particle-in-cell simulations indicate that radiation pressure acceleration becomes the dominant mechanism for the thinnest targets and CP pulses.