Spatial splitting of femtosecond laser pulse induced by infrared plasma grating

Spatial splitting of a probe femtosecond filament induced by plasma grating is observed in air. The refractive index is redistributed by the leading part of the probe pulse, inducing the defocusing of the trailing part with slight modification of its propagation direction. After undergoing a few cycles of total reflection between two plasma Walls, the trailing part is refocused at the trailing part of the plasma grating and escapes.