Protocol for measuring above-threshold ionization spectra driven by few-cycle laser pulses in frustrated tunneling ionization regime.

Above-threshold ionization (ATI) spectra in the frustrated tunneling ionization (FTI) regime demonstrate control of bound-state populations via the carrier-envelope phase (CEP). Here, we present a protocol for acquiring ATI spectra from argon gas driven by few-cycle laser pulses. We describe steps of few-cycle pulse generation, CEP stabilization and control, ATI spectral measurement, and data analysis. This approach enables potential applications in isolated attosecond pulse characterization. For complete details on the use and execution of this protocol, please refer to Wang et al.1.