Aerosol transparency-dependent femtosecond 1 kHz laser filamentation in air

This study explores the influence of aerosol transparency on femtosecond 1 kHz laser filamentation in air. The observations suggest that transparent and opaque aerosols may be associated with distinct filamentation pathways: (1) In transparent cases, scattering appears to play a dominant role, potentially modulated by droplet fragmentation processes related to the effective radius and effective variance, which in turn influence beam propagation characteristics; (2) In opaque cases, attenuation is governed primarily by absorption, accompanied by particle agglomeration effects. These primary trends may be further shaped by secondary processes, such as spectral blue-shift, electron attachment, and plasma-induced low-density channel formation, together contributing to the overall filamentation dynamics under different aerosol conditions. The experimental findings therefore point to a transparency-dependent balance between scattering and absorption that influences filament propagation and supercontinuum generation, offering useful implications for atmospheric laser applications.