Danish Ph.D. School in Nonlinear Science

Sponsored by the Danish Research Agency

Research area: NONLINEAR OPTICS

Extremely important applications of Nonlinear Science are made in nonlinear optics. Thus propagation and spatial evolution of light beams in nonlinear media is a central area. Exact 1+1 dimensional solitary wave solutions to the nonlinear Schrödinger equation were found more than 20 years ago. Such solitons will play an important role in the next generation of optical communication systems which will operate in the 100 Gbits/sec and higher regimes. At the moment such bit transmission rates can be obtained in purely optical systems, whereas electronic detectors and converters constitute an unsolved technological problem.

There is a growing interest in solitonlike structures in 2 and 3 spatial dimensions. These are generally unstable and may undergo catastrophic collapse in finite time. Combined theoretical, numerical, and experimental studies include:

• Creation of ultra-short pulses by nonlinear localization
• Robustness of solitons with stochastic phase matching in optical materials with and nonlinearities
• Conversion of optical data flow into electronic data using Josephson arrays
• Self-focussing and collapse of light beams in media with isotropic, anisotropic and long-range dispersive properties
• Self-focussing and collapse of light beams in media with isotropic, anisotropic and long-range dispersive properties
• Development, characterization, modelling and fabrication of new optical materials for applications in optical measurement systems
• Optical storage in nonlinear organic materials
• Intensity dependent phase-modulation, formation of patterns and dynamics of spatial solitons and optical vortices (dark spots) in organic materials (e. g. bacteriorhodopsin) and inorganic materials (e. g. photorefractive crystals)
• Parametric wave couplings and amplification in nonlinear photorefractive materials
• Mathematical modelling of switching devices, semiconductor lasers, quantum well lasers and distributed feed back lasers
• Nanostructures and quantum optical effects

The research is carried out in collaboration with The Microelectronic Center which has contacts with Danish industry.