(a) Electric field (black solid line) and instantaneous half-cycle period (red dashed line) of the optimized laser field. (b) The time-frequency picture of harmonic emission calculated by the full SFA. (c) Attosecond pulses by synthesizing single-atom harmonics between 118 and 195 eV. (d) Attosecond pulses generated after macroscopic propagation, in the near field and in the far field including small divergent (< 1 mrad) harmonic emissions only. Reprinted with permission from Ref. [96]. © (2014) by the American Physical Society.