Nonlinear spin-orbit interaction of light in liquid crystals

The spin-orbit interaction for photons is known to occur when light propagates through anisotropic and/or inhomogeneous media. We suggest that liquid crystalline materials, which are know to exhibit large orientational Kerr optical nonlinearities, can be used to modify the spin-orbit interaction at will through a purely optical third-order nonlinear process. Based on the recently introduced topologicla optical reorientation of liquid crystals here we present how the orbital angular momentum of the photon can be modified through `singular´ cross- and self-phase-modulation processes. The basic idea relies on the spin-to-orbital angular momentum conversion in light-induced spatially patterned anisotropic media.