Role of prepulses in the interaction of intense, ultrashort lasers with “structured” surfaces

P.P. Rajeev; S. Kahaly; S. Bagchi; S. Bose; P.P. Kiran; P. Ayyub; G. Ravindra Kumar

doi:doi:10.1051/jp4:2006133110

Issue		J. Phys. IV France Volume 133, June 2006


Page(s)		533 - 536
DOI		https://doi.org/10.1051/jp4:2006133110
Published online		16 June 2006

Inertial Fusion Sciences and Applications 2005
J.-C. Gauthier, et al.
J. Phys. IV France 133 (2006) 533-536
DOI: 10.1051/jp4:2006133110

Role of prepulses in the interaction of intense, ultrashort lasers with "structured" surfaces

P.P. Rajeev¹, S. Kahaly¹, S. Bagchi¹, S. Bose¹, P.P. Kiran¹, P. Ayyub¹ and G. Ravindra Kumar^{1, 0}

¹ Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400005, India

Abstract
We examine enhanced hard x-ray emission (20 - 200 keV) from plasmas produced on nanoparticles coated optically polished copper surface under different prepulse conditions. We observe that enhancement reduces with increasing prepulse intensity. The dynamics of the process is seen to be in the ps regime. We attribute this to preplasma formation on nanoparticles and subsequent modification/destruction of the nanostructure layer before the arrival of the main pulse. It is suggested that high-contrast ultrashort pulses are essential for nanoparticles to function as yield enhancers.