SCENARIO OF SPECTRUM ULTRABROADENING OF FEMTOSECOND LASER PULSE IN TRANSPARENT OPTICAL MEDIUM

摘要

On the basis of the analysis of the wave equations for an electrical field of radiation and without use of slowly varying envelope approximation the features of spectral ultrabroadening of ultrashort light pulses in transparent media are studied in detail. The results of numerical simulation of spectral supercontinuum evolution in medium with simultaneous electronic and electronic-vibrational nonlinearities are presented. It is shown that spectral ultrabroadening of extremely short pulse has the features: in the range of a normal group dispersion of the medium it is accompanied temporal broadening of pulse; in the range of a zero group dispersion of the medium it is accompanied by generation of high-frequency spectral components and shock enveloping wave of pulse with small broadening of pulse duration; in the field of an abnormal group dispersion of the medium it is accompanied by temporal compression of pulse down to 1-2 cycles of a light field.