title: Photo-isomerization fronts in dye-doped nematic liquid crystals.
abstract: An experimental study of the photo-isomerization dynamics in dye-doped nematic crystals is reported, which shows that, when the sample is illuminated by a Gaussian beam, and for high enough input power, a transition from the nematic to the isotropic phase takes place in the illuminated area. The two phases are spatially connected via a front propagating outward from the center of the beam and following the local intensity profile and thus inducing a photo-controlled optical aperture. The optical intensity and temperature fields on the sample follow the same dynamical profile. The front dynamics is described by a phenomenological bi-stable model with an inhomogeneous control parameter, directly related to the beam intensity profile.
authors.forename: V
authors.initials: V
authors.lastname: Odent
authors.forename: M G
authors.initials: MG
authors.lastname: Clerc
authors.forename: C
authors.initials: C
authors.lastname: Falcón
authors.forename: U
authors.initials: U
authors.lastname: Bortolozzo
authors.forename: E
authors.initials: E
authors.lastname: Louvergneaux
authors.forename: S
authors.initials: S
authors.lastname: Residori