Characteristics of femtosecond laser pulses propagating in atmospheric scattering media with spherical and nonspherical particles

To explore the propagation of ultrashort laser pulses in real atmospheric scattering media like fog and cloud, the influences of nonspherical and spherical particles on the propagation properties of 800 nm femtosecond laser pulses at different initial powers (P _in /P _cr = 100, 50, 10) were simulated with the stratified medium model developed based on the T-matrix method. The results indicated that the scattering properties of different particles indirectly influence the evolution of the laser intensity and the plasma concentration at a different propagation position z. For the same initial incident power, the intensities in the cylindrical particles were always higher than those in the spherical particles and the ellipsoidal particles due to the former weaker scattering attenuation. Additionally, as the energy of the incident pulse increases higher, the beam transmitted in the cylindrical particles gradually splits into distinct multifilament structures, while the fluence of the filament in the spherical particles and the ellipsoidal particles evolved into an irregular shape. Accordingly, the influences of the nonspherical and spherical particles on the filaments were obviously different.