Figure 8.

Polarization ellipse orientation map of the Poincaré–Bessel beam showing the infinite series of C-point singularity pairs. The white and black circles identify the star (polarization ellipse varying from 0 − π in the counterclockwise direction) and lemon (polarization ellipse varying from 0 − π in the clockwise direction) singularities, respectively. The insets show the polarization distribution and corresponding polarization ellipse orientation at C-point singularities.