| Abstract [eng] |
Filamentation of intense femtosecond laser pulses in transparent dielectric media exhibit universal features, such as long range propagation, which produces a narrow plasma channel, self-cleaning and robustness of the spatial mode, complex temporal dynamics, such as shock front generation, pulse splitting and compression. This dissertation aims to investigate filamentation scenarios of intense laser pulses in the range of zero to anomalous group velocity dispersion (GVD) of wide bandgap solid-state dielectric materials and characterize relevant nonlinear effects. Measurements show that filamentation in anomalous GVD results in similar dynamics of light bullet formation in sapphire and fused silica, despite differences in the optical properties of materials. It was also shown that the location of the input beam waist either on the entrance face or inside the nonlinear medium strongly affects the dynamics of spectral broadening. Harmonics generation in solids have uncovered the double peaked structure of third harmonic pulse that is generated in the conditions of large group and phase velocity mismatch and revealed that fifth and seventh harmonics are generated via cascaded four-wave mixing, eventually giving rise to broadband harmonics enhanced supercontinuum. It was also shown that under given operating conditions (the input pulse width, the length of the nonlinear medium, and the focusing condition) there exists an optimum input pulse energy, which produces the broadest supercontinuum spectrum in wide bandgap solid state dielectric materials. |
