2019-06-18T15:20:46Z (GMT) by
This visualization depicts the propagation dynamics of a multichromatic vortex beam as it undergoes a transition in its wavelength and topological charge in free space. Each frame represents a transverse cross section of the beam as it propagates along the z-direction. It is observed that the beam changes it color from red to green (twice) and also changes its topological charge with propagation, which is evident from the change in the number of intensity petals at the beam's center. Notably, while the wavelength (linear momentum) and topological charge (orbital angular momentum) can vary locally, the global momenta are always conserved.