  Conventionally, intrinsic orbital angular momentum (OAM) is associated with
phase vortices. However, our investigation into the propagation dynamics of 2D
superimposed catastrophe beams, termed cyclone catastrophe beams (CCBs),
reveals that these beams inherently exhibit rotation and possess OAM, distinct
from the typical connection to phase vortices. Our observations clearly show
these beams rotating during autofocusing propagation and particle manipulation,
confirming the presence of OAM. Theoretical calculations affirm that the OAM of
these beams is intrinsic and can be adjusted by varying the number of
superimposed beams. Furthermore, our interference and phase studies indicate
that, although CCBs exhibit phase vortices, they do not rotate around the
singularities of phase vortices and their total topological charges are zero.
This implies that the manifestation of OAM within CCBs does not rely on nonzero
topological charge of the presented phase vortices within CCBs. Especially,
eigenstates decomposition analysis illustrates that CCBs can be decomposed as a
composite of Laguerre-Gaussian (LG) modes with uneven fidelity, where the
topological charges of LG modes align with multiples of the superimposed
catastrophe beams but do not equal to the value of the OAM per photon within
CCBs, emphasizing the intrinsic OAM within CCBs and the absence of a connection
to phase vortices. Our findings not only advance the understanding of the
relationship between OAM and phase vortices but also pave the way for different
applications of OAM waves, catalyzing their development in optics and other
domains.
