102,374 research outputs found
K. A. Brzd1kiewicz, M. A. Karpierz, A. Fratalocchi and G. Assanto: “Discrete optical solitons in nematic liquid crystals
No full textwe propose the realization of liquid crystalline waveguide arrays, introducing the concept of a periodic photonic structure with refractive index changes controlled by an external voltage. Such voltage-controlled geometry in conjunction with the reorientational nonlinearity, offers a wealth of possibilities for the investigation of discrete phenomena, including discrete spatial solitons and their steering. Theory as well as experiments are reported
PHASE- AND POLARIZATION-INSENSITIVE ALL-OPTICAL SWITCHING BY SELF-GUIDING IN QUADRATIC MEDIA
No full textCollisional interactions of vectorial spatial solitary waves in type II frequency doubling media
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Self-confined light waves in nematic liquid crystals
No full textThe study of light beams propagating in the nonlinear, dispersive, birefringent and nonlocal medium of nematic liquid crystals has attracted widespread interest in the last twenty years or so. We review hereby the underlying physics, theoretical modelling and numerical approximations for nonlinear beam propagation in planar cells filled with nematic liquid crystals, including bright and dark solitary waves, as well as optical vortices. The pertinent governing equations consist of a nonlinear Schrödinger-type equation for the light beam and an elliptic equation for the medium response. Since the nonlinear and coupled nature of this system presents difficulties in terms of finding exact solutions, we outline the various approaches used to resolve them, pinpointing the good agreement obtained with numerical solutions and experimental results. Measurement and material details complement the theoretical narration to underline the power of the modelling
Simple physics of quadratic spatial solitons
No full textSpatial solitons in quadratically nonlinear media result from the interplay of parametric gain, diffraction and cascading phase shift. Their main features are well understood in mathematical terms, and several experiments have been successfully carried out which demonstrate their observability and most important properties. Here we provide an intuitive interpretation of some of the underlying physics, outlining the processes that govern their excitation, propagation and interaction forces
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