Polarization-gated surface enhanced optical fields for ultrafast electron acceleration

We show that the field polarization of the surface-plasmon-resonance enhanced optical field can be controlled to be linear with doubled intensity enhancement by using the polarization-gated excitation scheme with two counter-incident femtosecond laser pulses under the Kretschmann configuration, which is hence used for ultrafast electron acceleration to increase the maximum kinetic energy. The spatiotemporal evolution of the polarization-gated surface-enhanced optical field is studied by means of a simplified analytical model to describe the dynamical processes of electron acceleration, the kinetic energy and emission angular distributions of the accelerated electrons.