Maker fringes in the terahertz radiation produced by a 2-color laser field in air

The terahertz radiation produced by a 2-color femtosecond laser scheme strongly saturates and develops an oscillatory behavior with increasing power of the driving femtosecond laser pulses. This is explained by the formation of a plasma channel due to filamentation. Due to dispersion inside the filament and the Gouy phase shift, the phase difference between the 800 nm and 400 nm pulses varies along this plasma emitter. As a result, the local THz radiations generated along the filament interfere destructively or constructively, which manifests itself in the form of Maker fringes.