An attosecond research upsurge has been overwhelmingly rising since the establishment of novel light source—single isolated attosecond laser in extreme ultraviolet/X-ray resulted by strong field high-order harmonics generation (HHG). In this chapter, based on the electrostatic tunneling ionization from Coulomb potential modulation of atoms by strong light field, we scrutinized the intrinsic phase of high-order harmonics and analyzed qualitatively the salient dependence of two mainstream single isolated attosecond pulse generation techniques as polarization gating(PG) and amplitude gating(AG) on carrier-envelope phase (CEP) of femtosecond driving laser. The conclusion is that the optimized CEP corresponding to the highest intensity contrast between the main and sideband attosecond pulses is π/2 and 0 for polarization gating and amplitude gating, respectively. Further, an experimental implementation was given in detail to exemplify the tricks for optimum phase-matching process of HHG from the interaction of high-intensity femtosecond laser field with noble gas target. The effects of the relative location between Gaussian-shaped driving femtosecond laser field focus and the gas target source used on the HHG phase matching were studied, and the conclusion found that the expected position of gas target for optimum phase matching is always lying behind the focal point of the driving field used.
Part of the book: Modern Applications of Electrostatics and Dielectrics