title: Non linearly induced self waveguiding structure in dye doped nematic liquid crystals confined in capillaries.
abstract: We report on experiments dealing with the propagation of a collimated laser beam in a dye doped nematic confined in a capillary of optical fiber size. The nematic is aligned in a such a way that the source beam is self focused. The behavior of the beam - focusing, multifocus regime, filamentation and undulation - already observed in larger cylindrical geometry and pure nematic is shown here to be reproduced in the dye doped medium, at much lower powers. Another feature is reported here: a stable regime looking like a waveguide appears in certain conditions, in which the beam to propagate in a narrow tube. This regime is simply modeled in terms of saturated reorientation of the nematic.
authors.forename: M
authors.initials: M
authors.lastname: Warenghem
authors.forename: J
authors.initials: J
authors.lastname: Henninot
authors.forename: G
authors.initials: G
authors.lastname: Abbate