Generation of an intense single harmonic emission event and attosecond pulse from hydrogen molecular ion and its isotopic molecular ions with the assistance of half-cycle unipolar pulse

Abstract

Through controlling the charge resonance enhanced ionization process of the isotope molecules of hydrogen molecular ion, deuterium molecular ion and tritium molecular ion, the intense single harmonic emission event has been produced, which is beneficial to generate the single attosecond pulse. Moreover, the optimal laser parameter combinations for producing the intense harmonic spectra and attosecond pulses have been shown from 4 × 1014 W/cm2 to 7 × 1014 W/cm2. Further, by properly adding a half-cycle unipolar pulse, the selected single harmonic emission event can be further extended, which can support the shorter attosecond pulse with higher photon energy. Finally, by superposing these harmonics, a number of intense attosecond pulses shorter than 40 as can be obtained.