Guiding of meter scale AC discharges by laser filamentation in air

During propagation of intense laser pulses through atmosphere, owing to a dynamic competition between Kerr self-focusing, diffraction and ionization induced defocusing, a contracted beam of high peak intensity can be formed over long distances, provided the pulse input power exceeds a critical value (Pc ∼ 5 GW at 800 nm). During this process called filamentation [1], the pulse leaves in its wake a thin column of weakly ionized plasma (electron density ∼ 10¹⁶ cm^-3). Plasma filaments proved to be particularly useful for remote manipulation of high voltage discharges [2-5] and are of great interest for applications such as the laser lightning rod, virtual plasma antennas for radiofrequency transmission, plasma aerodynamic control or high voltage switch.