Nano-plasmonic-pump-probe effect on the intensity enhancement of attosecond pulse from hydrogen molecular ion

An effective scheme to extend the harmonic cutoff and enhance the harmonic yield from H-2(+) ion by using nano-plasmonic-pump-probe technology has been proposed. The essence of the present scheme is to use the pump pulse to steer H-2(+) to the multi-photon-resonance-ionization region, where the ionization probability can be remarkably enhanced. Then, a sequential probe pulse with a proper delay time can enhance the harmonic yield. Furthermore, by properly choosing the injected position of H-2(+) and by properly adding a controlling pulse, a single harmonic emission event with a broader harmonic plateau can be obtained. Finally, by the Fourier transformation of the selected harmonics on the harmonic plateau, a single 38 as pulse with intensity enhancement of 400 times can be obtained