Dispersion tuning via geometry induced resonances – a novel concept for scaling output powers in coherent supercontinuum generation

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The generation of light using nonlinear optical effects represents one highly addressed research area within current photonics due to its great potential in a series of areas including biophotonics or time-resolved spectroscopy. Supercontinuum generation (SCG), which is associated with the spectral broadening of an initially narrowband optical pulse has been identified as one of the most important mechanisms to generate light with desired properties. One very efficient way for broadband and tailored SCG relies on the fission of higher-order temporal solitons into their fundamental counterparts, which leads to the emission of excess energy into linear dispersive waves. This process is associated with a phase-matching process, which dominantly depends on the chromatic dispersion of the waveguide used.The overall aim of this project is to understand the influence of geometry-induced spectral resonances on the SCG process in hybrid fiber waveguides, defining a novel dispersion management scheme with the ultimate aim to unlock new soliton dynamics and to scale up energies in SCG. The conceptually new idea is to use strong spectral resonances, induced by microstructured elements of the specific fiber design used, to massively modify chromatic dispersion (in particular group velocity dispersion (GVD)), thus altering soliton dynamics and dispersive wave phase-matching processes. Nonlinear pulse propagation simulations that include all relevant effects will reveal how solitons and in particular the soliton fission process evolve in an environment of an orders of magnitude changing GVD in a narrow spectral interval. Various types of solid and hollow core fibers that have structural resonances close to the laser wavelength are to be implemented to investigate the impact of structural resonances experimentally. Preliminary simulations suggest that strong structural resonances allow maintaining the main dispersion characteristics (in particular the zero dispersion wavelength) when substantially increasing core diameters – a situation that is not achievable in Kagome or capillary waveguides. Therefore, geometry-induced resonances have the potential for scaling up power level in SCG by using exceptionally large core diameters, thus avoiding damage or gas ionization at the fiber input, which represents the main limiting factor in current schemes for SCG power scaling.The research output of this project will have impact in various areas of science and application such as quantum metrology, nonlinear physics or spectroscopy and is not restricted to fibers or a specific spectral domain. New types of ultrabroadband light sources for desirably addressing desired parts of the electromagnetic spectrum can be envisioned.