Fig. 4: Topological electromagnetic and energy flow structures.
From: Nondiffracting supertoroidal pulses and optical “Kármán vortex streets”
Magnetic field (a) and Poynting vector (b) distributions of a NDSTP with q2 = 100 and q3 = 1 at t = 0. The contours show the logarithm of the modulus of the corresponding vectors. a1 A zoom-in of the magnetic field with the arrow plot showing the vector distribution, the black dots referring to the singularities, and surrounding red arrows marking the type of the vector singularities (vortex and saddle) serving as guide to the eye. a2 Arrow plot showing a skyrmionic structure of magnetic field in the transverse (x-y) plane at z = 10, the insert highlights the deep-subwavelength features of the field vector reversal regions in the skyrmion texture. b1 A zoom-in of the Poynting vector field, where the arrow plot corresponds to the vector distribution, solid lines and dots mark the zeros of the Poynting vector, and red and blue arrows indicate areas with forward and backward energy flow, respectively. Unit of length: q1.
