Terahertz generation from laser-driven ultrafast current propagation along a wire target

摘要

Generation of intense coherent THz radiation by obliquely incidenting an intense laser pulse on a wire target is studied using particle-in-cell simulation. The laser-accelerated fast electrons are confined and guided along the surface of the wire, which then acts like a current-carrying line antenna and under appropriate conditions can emit electromagnetic radiation in the THz regime. For a driving laser intensity ～3 × 10~(18) W/cm~2 and pulse duration ～10 fs, a transient current above 10 KA is produced on the wire surface. The emission-cone angle of the resulting ～0.15 mJ (～58 GV/m peak electric field) THz radiation is ～30°. The conversion efficiency of laser-to-THz energy is ～0.75%. A simple analytical model that well reproduces the simulated result is presented.