Spider Structure of Photoelectron Momentum Distributions of Ionized Electrons from Hydrogen Atoms for Extraction of Carrier Envelope Phase of Few-Cycle Pulses

The spider structure in the photoelectron momentum distributions (PMDs) of ionized electrons from the hydrogen atom is simulated by solving the time-dependent Schrödinger equation (TDSE). We find that the spider structure exhibits sensitive dependence on carrier envelope phase (CEP) of the few-cycle pulses. To elucidate the striking CEP dependence of the spider structure, we select three physical parameters I_\rm L, I_\rm R, and I_\rm R/I_\rm L to quantitatively characterize the variations of the spider structure induced by altering the CEPs. I_\rm L is the sum of the left half panel of the transverse cut curves (i.e., the sum of all the negative momenta along the laser polarization direction), I_\rm R is the sum of the right half panel of the transverse cut curves (i.e., the sum of all the positive momenta along the laser polarization direction), and I_\rm R/I_\rm L is the ratio between the two sums. These parameters are shown to have monotonic relation with the CEP value, which is exploited to extract the CEPs. We anticipate that our method will be useful for obtaining CEPs encoded in the spider structure of PMDs.