Curved optical solitons subject to transverse acceleration in reorientational soft matter

We demonstrate that optical spatial solitons with non-rectilinear trajectories can be made to propagate in a uniaxial dielectric with a transversely modulated orientation of the optic axis. Exploiting the reorientational nonlinearity of nematic liquid crystals and imposing a linear variation of the background alignment of the molecular director, we observe solitons whose trajectories have either a monotonic or a non-monotonic curvature in the observation plane of propagation, depending on either the synergistic or counteracting roles of wavefront distortion and birefringent walk-off, respectively. The observed effect is well modelled in the weakly nonlinear regime using momentum conservation of the self-collimated beams in the presence of the spatial nonlocality of the medium response. Since reorientational solitons can act as passive waveguides for other weak optical signals, these results introduce a wealth of possibilities for all-optical signal routing and light-induced photonic interconnects

Spatial soliton all-optical logic gates RID F-7127-2011

We demonstrate some basic all-optical (electrically unbiased) logic gates in azobenzene liquid crystalline cells, exploiting their large nonlinearity for light localization and the trans-cis photoisomerization for all-optical external control. Spatial solitons were excited at microwatt power levels at 632.8 nm, whereas gating and switching were achieved with milliwatt beams at 409 mn

Macroscopic direct observation of optical spin-dependent lateral forces and left-handed torques

Observing and taming the effects arising from non-trivial light-matter interaction has always triggered scientists to better understand nature and develop photonic technologies. However, despite tremendous conceptual advances 1,2 , so far there have been only a few experimental proposals to reveal unusual optomechanical manifestations that are hardly seen in everyday life, such as negative radiation pressure 3,4 , transverse forces 5,6 or left-handed torques 7. Here, we report naked-eye identification of spin-dependent lateral displacements of centimetre-sized objects endowed with structured bire-fringence. Left-handed macroscopic rotational motion is also reported. The unveiled effects ultimately rely on spin-orbit optical interactions and are driven by lateral force fields that are five orders of magnitude larger than those reported previously , as a result of the proposed design. By highlighting the spin-orbit optomechanics of anisotropic and inhomogeneous media, these results allow structured light-matter interaction to move from a scientific curiosity to a new asset for the optical manipulation toolbox