Study of Hot Electrons by Measurement of Optical Emission from the Rear Surface of a Metallic Foil Irradiated with Ultraintense Laser Pulse

Hot electrons and optical emission are measured from the rear surface of a metallic foil. The spectra of the optical emission in the near infrared region have a sharp spike around the wavelength of the incident laser pulse. The optical emission is ascribed to coherent transition radiation due to microbunching in the hot electron beam. It is found that the optical emission closely correlates with the hot electrons accelerated in resonance absorption.