  Superposition of two independent orthogonally polarized beams is a
conventional principle of creating a new light beam. Here, we intend to achieve
the inverse process, namely, extracting inherent polarization modes from a
single light beam. However, inherent polarization modes within a light beam are
always entangled so that a stable polarization is maintained during propagation
in free space. To overcome this limitation, we report an approach that breaks
the modulation symmetry of a light beam, thereby disentangling the inherent
polarization modes. Using polarization mode competition along with an optical
pen, polarization modes are extracted at will in the focal region of an
objective lens. This work demonstrates polarization mode extraction from a
light beam, which will not only provide an entirely new principle of
polarization modulation but also pave the way for multidimensional manipulation
of light fields, thereby facilitating extensive developments in optics.
