Control of Nonlinear Optical Structures: From the Guiding of Dissipative Solitons to Spatio– temporal Synchronisation

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The development and characterisation of open loop control methods for spatiotemporal optical structures were the main objectives treated in this thesis. For this purpose, the LCLV single feedback system, which was chosen as model system, is particularly well suited due to large variety of patterns found in the system and because the system exhibits extremely large aspect ratios. Since the principal behaviour of the LCLV system had been explored before and the self-organised patterns spontaneously forming in the systems were known my main interest was to study the control the spontaneous behaviour of dissipative optical solitons and to explore spatio– temporal synchronisation in the LCLV system. Prior to the treatment of the main objective: Control of the LCLV single feedback system, I have in a small excursion reported on the modulation instability of incoherent optical beams propagating in photorefractive media. In this context, it was shown that both a first threshold of modulation instability, where the uniform beam breaks up into stripes, and the secondary threshold, where the beam completely breaks up into two dimensional filaments, can be controlled by changing the degree of the beam’s spatial coherence. In studying the control of modulation instability with incoherent beam a key prerequisite for controlling the interaction behavior of propagating optical solitons has been characterised. Using mutually incoherent or phase engineered optical solitons the interaction behaviour of solitons can be modified enabling the creation of more densely packed soliton arrays.