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SPACE-TIME COMPLEXITY IN NON LINEAR OPTICS

Objective


An understanding of spatiotemporal effects in nonlinear optical systems was achieved, with significant progress being made on the study of pattern formation in space and time in passive and active bulk optical media and fibres. Research activities spanned the entire spectrum of currently topical nonlinear optics problems. The derivation of universal complex order parameter equations describing the onset of transverse spatial patterns near a critical point was an important development. Hexagonal and square patterns were found to be the norm for laser beams counterpropagating in bulk Kerr nonlinear media. Single feedback Kerr thin slabs allowed for a more quantitative analysis of pattern formation. A rich phenomenology was observed, including a weakly turbulent behaviour. The study of active media focused on pattern formation in wide aperture 2-level and Raman lasers. These were viewed as prototypical systems for the more complicated wide aperture semiconductor lasers but are also very interesting in their own right. Travelling wave solutions were discovered to be the natural nonlinear modes of these systems indicating that such lasers tend to emit off axis. There is compelling evidence in recent injection locking experiments in broad area semiconductor lasers that off axis injection of a weak external probe beam couples most efficiently into such a travelling wave solution. Reflecting transverse boundaries fundamentally change the nature of the solutions with source-sink pairs coexisting at large enough aspect ratios. Analogies between 1-dimensional transverse patterns and time domain patterns in optical fibres were exploited. The role of temporal dispersion, gain and polarization was investigated in detail.
Space-time complexity in Nonlinear Optics remains essentially unexplored. The potential impact of thischallenging field on our understanding of nonlinear science and in establishing a new research area in nonlinear optics, forms the major objective of the Twinning partnership. The wide ranging expertise of the individual partners in mathematical analysis, computer simulation, fundamental physics and advanced optics applications will be pooled, to provide a uniquely European dimension in a leading edge scientific endeavour. Central to the goals of the twinning is intensive computer simulation with real-time graphical visualisation. Transputer based systems will provide innovative computational tools as a low cost alternative computing strategy.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Heriot-Watt University
Address
Riccarton, Lord Balerno Building
EH14 4AS Edinburgh
United Kingdom

Participants (3)

Fondazione "Ugo Bordoni"
Italy
Address
Via Baldassarre Castiglione 59
00142 Roma
UNIVERSITE DE NICE - SOPHIA ANTIPOLIS
France
Address
Parc Valrose
06108 Nice
University of Strathclyde
United Kingdom
Address
50 George Street
G1 1BA Glasgow