Home – Home – Jornals – Atmospheric and Oceanic Optics 2016 number 3

Formation of light bullets is numerically investigated during filamentation of near and mid-IR femtosecond pulses in condensed media at anomalous group velocity dispersion. On the example of filamentation of microjoule pulses at wavelengths of 1.4, 1.8, and 2.2 mm in fused silica at powers slightly exceeding the critical self-focusing power, it is established that the subsequent light bullets are not formed if the dispersive length is much bigger and much smaller than the self-focusing length. It is shown that the peak intensity in light bullets does not depend on the initial pulse intensity, is determined by the multiphoton order of laser plasma generation, and increases with the order. In fused silica, the peak intensity in a light bullet makes about 40 TW/cm² during filamentation of microjoule pulses at a wavelength of 1.4-2.2 mm, and in CaF₂, the peak intensity reaches 120 TW/cm² for pulses at a wavelength of 3 mm. The light bullet is a short-lived formation existing on less than 1 mm distance. It is found that the change in the pulse energy at a wavelength of 3 mm during filamentation in CaF₂ influences the number of light bullets and does not increase their time of life.