Fig. 1. Schematic of photoelectron energy spectrum measurement based on attosecond streak camera

Fig. 2. Schematic of ultrafast dynamic model. (a) Energy-time distribution of initial photoelectron wave packet; (b) initial energy distribution of attosecond pulse and (c) photoelectron energy spectrum when IR laser delay is 0; (d) initial energy distribution of attosecond pulse and (e) photoelectron energy spectrum when IR laser delay is -0.667 fs; (f) vector potential of IR laser versus time; (g) photoelectron spectrum without IR laser; (h) streak photoelectron spectrum calculated by FROG model under

Fig. 3. Effects of different attosecond pulse chirps on stripe photoelectron energy spectrum. (a)(d)Attosecond pulses with positive chirps; (b)(e) attosecond pulses with negative chirps; (c)(f) chirp-free attosecond pulses

Fig. 4. Streak spectrum to be reconstructed and all parameters versus attosecond pulse duration and chirp.(a) Streak spectrum to be reconstructed; (b) trace of local maximum intensity for different delay time; (c) Imin/Imaxversus attosecond pulse duration and chirp; (d) τmax versus attosecond pulse duration and chirp; (e) fFWHMmax versus attosecond pulse duration and chirp

Fig. 5. Schematic of method for determining attosecond pulse duration and chirp value based on specific equal-value lines

Fig. 6. Intensity envelope and phase distributions of pulse reconstructed by different methods. (a) ELR method; (b) FROG-CRAB method