Identifying backward-rescattering photoelectron hologram with orthogonal two-color laser fields

Backscattering photoelectron hologram (BPH) originating from direct and backward-rescattering electrons encodes important structural information and ultrafast dynamics of the underlying processes. However, the BPH is usually overshadowed by other interference structures in the photoelectrons momentum spectra, preventing a direct extraction of information using BPH. Here we theoretically demonstrate disentanglement of the BPH from other types of interference with the orthogonal two-color field, where a weak orthogonal component is used to streak the BPH. By carefully adjusting the relative phase of the two-color field, the BPH is effectively separated from other interferences in the photoelectron momentum spectra and thus the BPH is unambiguously identified. This takes a significant step to time-resolved imaging of the attosecond dynamics with strong-field photoelectron holography.