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