Model of high-order harmonic generation from laser interaction with a plasma grating

Harmonic generation from linearly polarized high-intensity short-pulse laser normally impacting a solid plasma grating is investigated using analytical modeling and particle-in-cell simulation. It is found that when the radiation excited by the relativistic electron quiver motion in the laser fields suitably matches a harmonic of the grating periodicity, it will be significantly enhanced and peak with narrow angular spread in specific directions. The corresponding theory shows that the phenomenon can be attributed to an interference effect of the periodic grating on the excitation.