  For a circularly polarized single-color field at a central frequency of
$2\omega$ the final electron momentum distribution upon strong field ionization
does not carry any information about the phase of the initial momentum
distribution. Adding a weak, co-rotating, circularly polarized field at a
central frequency of $\omega$ gives rise to a sub-cycle interference pattern
(holographic angular streaking of electrons (HASE)). This interference pattern
allows for the retrieval of the derivative of the phase of the initial momentum
distribution after tunneling $\phi^{\prime}_{\mathrm{off}}(p_i)$. A
trajectory-based semi-classical model (HASE model) is introduced which links
the experimentally accessible quantities to
$\phi^{\prime}_{\mathrm{off}}(p_i)$. It is shown that a change in
$\phi^{\prime}_{\mathrm{off}}$ is equivalent to a displacement in position
space $\Delta x$ of the initial wave packet after tunneling. This offset in
position space allows for an intuitive interpretation of the Wigner time delay
$\Delta \tau_W$ in strong field ionization for circularly polarized
single-color fields. The influence of Coulomb interaction after tunneling is
investigated quantitatively.
