Abstract
This paper presents the results of studies of the physical nature of the electrodynamic angular momentum of a stable CV ++1 vortex in a few-mode fiber. It shows that the angular momentum of a CV ++1 vortex can be conventionally divided into orbital and spin angular momenta. The longitudinal component of the fundamental HE +11 mode on the axis of the fiber has a pure screw dislocation with a topological charge of e=+1. The longitudinal component of a CV ++1 vortex also has a pure screw dislocation on the axis of the fiber with a topological charge of e=+2. Therefore, perturbation of a CV ++1 vortex by the field of the fundamental HE +11 mode removes the degeneracy of the pure screw dislocations of the longitudinal and transverse components of the field and breaks down the structural stability of the CV ++1 vortex. As a result, an additional azimuthal flux of energy with an angular momentum opposite to that of the fundamental flux is induced. An analogy is drawn between the stream lines of a perturbed CV vortex and the stream lines of an inviscid liquid flowing around a rotating cylinder. Studies of the evolution of a CV vortex in a parabolic fiber show that they are structurally stable when acted on by the perturbing field of the HE +11 mode. However, perturbing a CV ++1 1 vortex of a stepped fiber with the field of the HE +11 mode destroys the structural stability of the vortex. It is found that the propagation of a circularly polarized CV vortex can be represented as a helical wavefront screwing into the medium of the fiber. The propagation of a linearly polarized vortex in free space is characterized by the translational displacement (without rotation) of a helical wavefront.
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References
A. A. Sokolov, Introduction to Quantum Electrodynamics (GIFML, Moscow, 1958).
W. Heitler, The Quantum Theory of Radiation (Clarendon Press, Oxford, 1954; IL, Moscow, 1956).
L. Allen, M. W. Beijersbergen, and R. J. C. Spreeuw, Phys. Rev. A 45, 8185 (1992).
H. He, N. R. Heckenmberg, and H. Rubinsztein-Dunlop, J. Mod. Opt. 42, 217 (1995).
H. He, M. E. Friese, and N. R. Heckenber, Phys. Rev. Lett. 75, 826 (1996).
A. V. Volyar and T. A. Fadeeva, Pis’ma Zh. Tekh. Fiz. 22, No. 17, 69 (1996) [Tech. Phys. Lett. 22, 719 (1996)].
A. W. Snyder and J. D. Love, Optical Waveguide Theory (Chapman and Hall, New York, 1983; Radio i Svyaz’, Moscow, 1987).
A. V. Volyar and T. A. Fadeeva, Pis’ma Zh. Tekh. Fiz. 22, No.8, 63 (1996) [Tech. Phys. Lett. 22, 333 (1996)].
I. V. Basistiy, V. Yu. Bazhenov, M. S. Soskin, and M. V. Vasnetsov, Opt. Comm. 103, 422 (1993).
Ya. B. Zel’dovich and A. D. Myshkis, Elements of Applied Mathematics (Mir, Moscow, 1976).
T. Poston and I. Stewart, Catastrophe Theory and Its Applications (Pitman Publishing, Marshfield, Mass., 1978; Mir, Moscow, 1980).
P. Zhermen, Mechanics of Continuous Media (Mir, Moscow, 1965).
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Pis’ma Zh. Tekh. Fiz. 23, 74–81 (November 12, 1997)
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Volyar, A.V., Fadeeva, T.A. Angular momentum of the fields of a few-mode fiber: I. A perturbed optical vortex. Tech. Phys. Lett. 23, 848–851 (1997). https://doi.org/10.1134/1.1261907
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DOI: https://doi.org/10.1134/1.1261907