  Orthogonal circularly polarized light is essential for multiplexing tunable
metasurfaces. Mainstream spin-decoupled metasurfaces, consisting of numerous
meta-atoms with mirror symmetry, rely on the cooperative modulation of the
Pancharatnam-Berry (PB) phase and the propagation phase. This paper
demonstrates spin-decoupled functionality through the synergistic utilization
of planar chiral meta-atom phase response and PB phase. Based on the Jones
calculus, it has been found that meta-atoms with chiral C2-symmetry owns a
larger geometric parameter range with high cross-polarization ratio compared to
those with mirror symmetry or higher symmetries at the same aspect ratio. This
characteristic is advantageous in terms of enabling high-efficiency
manipulation and enhancing the signal-to-noise ratio. As an example, 10 kinds
of C2-symmetry chiral meta-atoms with a H-like shape are selected by the
self-adaptive genetic algorithm to attain a full 2$\pi$ phase span with an
interval of $\pi$/5. To mitigate the additional propagation phase change of the
guided modes originated from the arrangement alternation upon the rotation of
the meta-atoms, the enantiomer of chiral meta-atoms and its PB phase delay are
adopted to minimize the difference between the actual and desired target
phases. A polarization-insensitive metalens and a chiral virtual-moving
metalens array are designed to demonstrate the spin-decoupled function with
both high efficiency and signal-to-noise ratio. The work in this paper may
trigger more exciting and interesting spin-decoupled multiplexing metasurfaces
and broaden the prospect of chiroptical applications.
