Strong sub-terahertz surface waves generated on metal wires by relativistic-intensity laser pulses

We review an efficient method for strong terahertz surface wave generation by relativistic-intensity (>10¹⁸ W/cm²) laser pulses. Ultrafast field propagation along a metal wire driven by a femtosecond laser pulse with a relativistic intensity is characterized by femtosecond electron deflectometry and electro-optic sampling. We found that the field propagating at the speed of light is a half-cycle transverse-magnetic surface wave excited on the wire and a considerable portion of the kinetic energy of laser-produced fast electrons can be transferred to the sub-surface wave.