High-order harmonic enhancement in nanowire by inhomogeneous field

We theoretically investigate high-order harmonic generation from nanowire in inhomogeneous laser field. By solving the time-dependent Schrodinger equation, the simulated harmonic spectrum exhibits a double-plateau structure. The cutoff of the second plateau is extended and the intensity of the high-order harmonics in the second plateau is increased by about two to three orders of magnitude compared with that from the homogeneous laser field. Moreover, we analyze the influence of the inhomogeneous laser field polarization orientation to the nanowire. It is shown that the intensity of the high-order harmonics in the second plateau can be effectively controlled by varying the inhomogeneity parameter and the laser field polarization orientation to the nanowire. These phenomena are attributed to the time-dependent population of the electron, which has a strong relevance with the intensity of the harmonic.