2 research outputs found
Geometrical Optics of Beams with Vortices: Berry Phase and Orbital Angular Momentum Hall Effect
We consider propagation of a paraxial beam carrying the spin angular momentum
(polarization) and intrinsic orbital angular momentum (IOAM) in a smoothly
inhomogeneous isotropic medium. It is shown that the presence of IOAM can
dramatically enhance and rearrange the topological phenomena that previously
were considered solely in connection to the polarization of transverse waves.
In particular, the appearance of a new-type Berry phase that describes the
parallel transport of the beam structure along a curved ray is predicted. We
derive the ray equations demonstrating the splitting of beams with different
values of IOAM. This is the orbital angular momentum Hall effect, which
resembles Magnus effect for optical vortices. Unlike the recently discovered
spin Hall effect of photons, it can be much larger in magnitude and is inherent
to waves of any nature. Experimental means to detect the phenomena is
discussed.Comment: 5 pages, 2 figure
Topological spin transport of photons: "magnetic monopole" gauge field in Maxwell equations and polarization splitting of rays in periodically inhomogeneous media
Topological spin transport of electromagnetic waves (photons) in stationary
smoothly inhomogeneous isotropic medium is studied. By diagonalizing photon
kinetic energy in Maxwell equations we derive the non-Abelian pure gauge
potential in the momentum space, which in adiabatic approximation for
transverse waves takes the form of two Abelian U(1) potentials corresponding to
magnetic monopole-type fields. These fields act on circularly polarized waves
resulting in the topological spin transport of photons. We deduce general
semiclassical (geometrical optics) ray equations that take into account a
Lorentz-type force of the magnetic-monopole-like gauge field. Detailed analysis
of rays in 3D medium with 2D periodic inhomogeneity is presented. It is shown
that rays located initially in the inhomogeneity plane experience topological
deflections or splitting that move them out from this plane. The dependence of
the rays' deflection on the parameters of the medium and on the direction of
propagation is studied.Comment: 16 pages, 3 figure