High field ultrafast laser driven electron accelerator and novel radiation light source (Invited Paper)

High field ultrafast laser pulse can instantaneously generate intense electromagnetic fields at a very small scale of focus, in which microscale region it is expected to generate compact electron accelerators and new radiation sources. Here we present a principle of quasi particle coherent radiation amplification using a free electron pumping. When an ultrafast laser focus on a metal wire waveguide, the excited electron pulse pumps surface plasmon polaritons and achieves coherent amplification, which is observed by the ultrafast optical pump-probe method. Using this quasiparticle source with natural surface modes, we have demonstrated a new method of waveguide-coupled terahertz electron acceleration with electron energy gain exceeding MeV at an acceleration distance of 5 mm within the waveguide. The electrons locked phase with laser are crucial for the direct acceleration and pulse control of electrons. We propose a scheme to generate attosecond electron pulse (~260 as) from solid surface under relativistic laser field.