Energy shifts of Ti Kα induced by polarized ultrashort infrared laser pulse

One promising application of laser-matter interactions is generating hot suprathermal electrons with keV-MeV energy, which enables excitation of the K shell of the target material. Recently, Dr. G. Cristoforetti (Intense Laser Irradiation Laboratory, Italy) and his colleagues have reported some interesting experiments on the laser pulse polarization effect on the Kα yield and line shape. The research group studied the interaction of an ultrashort laser pulse (λ = 800 nm, τ = 40 fs) with a Ti foil under intense irradiation. The K X-ray emission was analyzed by a quartz crystal and a CCD camera, and it was found that the energy of Kα lines shift a few eV up to around 15 eV, depending on the pulse polarization. Such dependence can be discussed by considering the efficiency of hot electron generation. For more information, see the paper, "Spatially resolved analysis of Kα x-ray emission from plasmas induced by a femtosecond weakly relativistic laser pulse at various polarizations", G. Cristoforetti et al., Phy. Rev. E87, 023103 (2013).