This issue contains a collection of papers devoted to
dynamics and pattern formation in nonlinear optical systems. The
articles originate from contributions to a conference on
control of complex behaviour in optical systems and
applications (COCOS) held in Münster, Germany, in October 1999.
It was the second of a series of Euroconferences on Trends in
Optical Nonlinear Dynamics. Physical Problems and Applications
funded by the European Union through its TMR Programme and
co-sponsored by various institutions. The topics of the
conference covered all kinds of complex self-organization
phenomena in nonlinear optics and this diversity is also
reflected in the papers. The contributions cover a great variety
of material systems (atomic vapours, nonlinear crystals,
photorefractives, liquid crystal light valves, fibres,
semiconductors, solid-state lasers, ...) and interaction
schemes (nonlinear resonators, single-mirror feedback schemes,
nonlinear beam propagation, four-wave mixing).
Though there is emphasis on the characterization and control of
spatial structures including extended patterns as well as
localized states, domain walls and solitons, several papers also
discuss temporal instabilities and develop strategies for
stabilization or optimal steering. In both fields there are a
number of contributions considering semiconductor systems and
their control. This is a strong indication that nonlinear
dynamics in optics is on its way to making more and more useful
contributions to applications. Some papers are also providing
connections between two fields, either between patterns and
localized structures or between purely temporal and spatial
phenomena. They analyse e.g. the dynamics of coupled lasers,
pulse trains in nonlinear fibres or spatiotemporal chaos. Last
but not least, papers investigating vectorial effects or coherence
phenomena (e.g. in inversionless amplification) demonstrate that
there are features of optical systems that have no obvious
counterpart in nonlinear systems of other kinds.
The diversity of the papers is even more remarkable, since the
collection of papers presented here does not form `proceedings'
in a comprehensive sense, but covers about twenty percent of
the contributions to COCOS only. Nevertheless, it is our opinion
that they are somehow representative of the European activities
in the field of nonlinear dynamics in optics. It is our hope
that the papers give an idea of how nonlinear optics can help in
understanding general features of self-organization common to all
kinds of complex systems on the one hand, and on the other hand
how it can provide well-controlled, high performance devices for
the photonic applications of tomorrow.
Finally, we thank the Editors of the journal for providing the
forum for this presentation and the Editorial Office for all the
work done.