| Abstract [eng] |
In 1995 Braun and co-workers reported the observation of self-channeling of femtosecond laser pulses over 20 m in air. This first observation of femtosecond filament triggered a series of studies, which discovered an exciting physics beyond the interaction of ultrashort laser pulses with transparent dielectric media. This dissertation aims at comprehensive study of transient spatiotemporal phenomena (space-time transformations, pulse splitting and compression, filament propagation dynamics, supercontinuum generation and multiple filamentation) that take place during self-focusing of intense femtosecond laser pulses in various self-action regimes in transparent dielectric media with instantaneous Kerr nonlinearity. Various nonlinear optics diagnostic methods (three dimensional mapping, auto- and cross-correlation measurements, frequency resolved optical gating measurements), spatially resolved frequency spectra measurements, statistical analysis of spectral intensities and energies, numerical simulations were employed. The dissertation addresses important issues regarding complete physical understanding of the evolution cycle of femtosecond filaments in normally dispersive media, physical nature of spatiotemporal light bullets generated by filamentation in the anomalous group velocity regime, detailed statistical aspects of supercontinuum generation, and spatiotemporal characterization of multiple filaments. Analysed factors are useful for practical applications when generation of controlled spatio-temporal structures, extreme optical waves (or contrary - suppression of them if the nonlinear optical system needs to be stabilised) is required. Furthermore, the research uncovered general and specific properties of extreme optical events, as compared with their analogs in other physical system (ocean surface wave, Bose-Einstein condensates, superfluids, financial markets etc.). |
