Fig. 4: Transition of topological state and skyrmion number of 2D optical skyrmions.
From: Topological state and number transitions of optical skyrmions upon free-space beam propagation
a Simulated longitudinal intensity distribution of 2D optical skyrmions within the range of z = 0–30 cm. b Simulated (green spherical dotted line plot) and experimental (magenta square dotted line plot) results of the skyrmion number varying with propagation distance. c The experimental intensity, polarization, topological state and number of 2D optical skyrmions at different longitudinal positions z = 5 cm, z = 10 cm, z = 15 cm, z = 20 cm, z = 25 cm.
