Generation of High-Current Photoelectrons Using a Subpicosecond Ultraviolet Laser

Abstract
Laser-induced photoelecrons produced using an ultrashort pulse laser and a metal cathode have been accelerated to relativistic energy. The pulse duration and the wavelength of the laser are 0.5 ps and 248 nm, respectively. The acceleration voltage is 0.61 MV. The current density at the cathode surface was estimated to be about 1 kA/cm2, which is about one hundred of times higher than the theoretically calculated value of the space-charge-limited current density given by the Langmuir equation. Theoretical analysis of the space-charge-limited current density for an ultrashort electron bunch was performed.