title: Phase-transition oscillations induced by a strongly focused laser beam.
abstract: We report the observation of a surprising phenomenon consisting in a oscillating phase transition which appears in a binary mixture when this is enlightened by a strongly focused infrared laser beam. The mixture is poly-methyl-meth-acrylate (PMMA)-3-octanone, which has an upper critical solution temperature at T(c)=306.6K and volume fraction ϕ(c)=12.8% [Crauste et al., arXiv:1310.6720, 2013]. We describe the dynamical properties of the oscillations, which are produced by a competition between various effects: the local accumulation of PMMA produced by the laser beam, thermophoresis, and nonlinear diffusion. We show that the main properties of this kind of oscillations can be reproduced in the Landau theory for a binary mixture in which a local driving mechanism, simulating the laser beam, is introduced.
authors.affiliation: Université de Lyon, Laboratoire de Physique, École Normale Supérieure de Lyon, CNRS UMR5672, 46, Allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Clémence
authors.initials: C
authors.lastname: Devailly
authors.affiliation: Université de Lyon, Laboratoire de Physique, École Normale Supérieure de Lyon, CNRS UMR5672, 46, Allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Crauste-Thibierge
authors.affiliation: Université de Lyon, Laboratoire de Physique, École Normale Supérieure de Lyon, CNRS UMR5672, 46, Allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Artyom
authors.initials: A
authors.lastname: Petrosyan
authors.affiliation: Université de Lyon, Laboratoire de Physique, École Normale Supérieure de Lyon, CNRS UMR5672, 46, Allée d'Italie, 69364 Lyon Cedex 07, France.
authors.forename: Sergio
authors.initials: S
authors.lastname: Ciliberto