Fig. 1. Bouquet‑like photoelectron momentum distributions induced by intense laser ionization of hydrogen atom. (a)-(f) Photoelectron momentum distributions; (g) four saddle point zones and laser field (o.c. presents optical cycle)

Fig. 2. Above-threshold-ionization fringes in momentum space and energy space and ponderomotive energy, ionization energy and α versus laser intensity. (a)(c) Semi-circle-shaped above-threshold ionization fringes in momentum space; (b)(d) above-threshold ionization fringes in energy space; (e) ponderomotive energy, ionization energy and α versus laser intensity

Fig. 3. Inner-cycle interference fringes as well as arc-center positions p_0xand interference fringe quantity along p_x and p_{ydirections versus laser intensity. (a)(b) Arc-shaped inner-cycle interference fringes; (c) inner-cycle interference arc-center positions p0x versus laser intensity; (d) interference fringe quantity along px and pydirections versus laser intensity}

Fig. 4. Triple slit model for bouquet-like photoelectron momentum distributions and interferometric maxima in electron bouquet-like photoelectron momentum distributions. (a) Triple slit model for bouquet-like photoelectron momentum distributions, where the red, green and blue curves represent the wavefront of three groups of electron waves, and the yellow intersection is the position of interferometric maxima; (b) interferometric maxima in electron bouquet-like photoelectron momentum distributions