The article considers depolarization effects caused by the hyperfine interaction between the total electronic-shell angular momentum and the nuclear spin. A pump–probe scheme is examined, and the corresponding photoelectron angular distributions are obtained. The analytical results are illustrated by calculations for a hydrogen-like target: a single electron in a Coulomb potential. Three most representative combinations of polarizations of the pump and probe fields are considered: colinear polarizations (1) and circularly polarized fields with the same (2) and opposite (3) helicities.
Gnedovskaya et al. (Mon,) studied this question.