Photoemission enhancement from copper illuminated with a radial polarized femtosecond laser pulse

We have developed a novel photocathode gun gated by the laser-induced Schottky-effect. This new type of gun utilizes laser coherency to aim at a compact femtosecond laser oscillator as an IR laser source using Z-polarization on a metal photocathode. If the Schottky or tunnelling effect due to the Z-field is dominated, we expect that electrons will be emitted from the outermost surface of the metal cathode and extracted with the external electric field of the RF cavity. This Z-polarization scheme reduces the laser photon energy to excite the cathode with a longer wavelength by reducing its work function due to the Schottky effect. Before this epoch-making scheme emerged, photocathode guns had never utilized a laser´s coherency itself.