Electron radiography using hot electron jets from sub-millijoule femtosecond laser pulses

Abstract

Electron jets produced in the intermediate intensity range of 1015 to 1017 W/cm2 from submillijoule 120 fs Ti:Sapphire laser pulses focused to spots of a few microns in diameter have been characterized. The experimental results show strong emission of hot electrons with energies from 80 keV to above 250 keV from microplasmas created with both p- and s-polarized 250 μJ laser pulses. The electron jets with energies above 250 keV are observed to be highly directional. The electron jets are observed in the plane of polarization of the laser electric field for both p- and s-polarized laser pulses. The hot electrons emitted from these femtosecond laser plasmas have also been used for radiographic imaging. It is expected that the short initial duration of these electron pulses would make them useful for time resolved applications.