@Workshop{Supelec493,
author = {Nicolas Marsal and Delphine Wolfersberger and Marc Sciamanna and Germano Montemezzani and Dragomir Neshev},
title = {{Etude des éffets d’un lattice optique sur un pattern hexagonal}},
year = {2008},
booktitle = {{Journée DYCOEC}},
month = {Feb},
address = {Nice (France)},
url = {http://www.coria.fr/dycoec/spip.php\'earticle44},
abstract = {Periodic photonic structures enable novel possibilities for
manipulation of the fundamental aspects of wave propagation
including enhancement of optical nonlinearity and control of
light emission and radiation. The interplay between
nonlinearity, optical gain, and bandgap effects gives rise to
new physical phenomena on control of nonlinear dynamics and
spatial pattern formation. This has inspired recent interest in
dissipative discrete systems leading to the prediction of
localised structures or bandgap manipulation of modulational
instability. Despite the strong theoretical activities,
experimental studies of such phenomena are lacking. In this
work, we present what is to our knowledge the first
experimental observation of band-gap manipulation of
modulational instability in a periodic nonlinear dissipative
system. We use a setup based on a photorefractive BaTiO3
crystal in a single feedback mirror configuration giving rise
to hexagonal pattern formation. Additionally, we impose a
square optical lattice to induce a two or one-dimensional
photonic band-gap structure with variable parameters. We show
that by varying the lattice strength and periodicity we can :
induce patterns of square symmetry ; or suppress the
modulational instability when the position of the lattice
bandgap coincides with the instability gain. We also study how
the threshold for modulational instability depends on the
lattice strength and periodicity. We believe that similar
manipulation of the nonlinear dynamics can also be potentially
observed in lasers with large mode area and embedded photonic
crystal structures.
}
}