Polarization-dependent supercontinuum generation from light filaments in air

Area of Science:

• Nonlinear Optics
• Laser Physics
• Atmospheric Optics

Background:

• Supercontinuum generation is a key phenomenon in nonlinear optics.
• Laser filamentation in air enables long-distance propagation of intense ultrashort pulses.
• Polarization effects can significantly influence nonlinear optical processes.

Purpose of the Study:

• To investigate the impact of laser polarization on supercontinuum emission.
• To compare conversion efficiencies for circular versus linear polarization.
• To understand polarization-dependent properties in long-distance laser filamentation in air.

Main Methods:

• Generation of filaments using intense femtosecond laser pulses in air.
• Propagation of laser pulses over long distances.
• Measurement of supercontinuum emission properties.
• Comparison of polarization states (circular vs. linear).

Main Results:

• Supercontinuum emission was generated from laser-induced filaments in air.
• Conversion efficiency from 800-nm fundamental to white light was measured.
• Higher conversion efficiency was observed for circular polarization compared to linear polarization.
• This effect was prominent above the air breakdown threshold intensity.

Conclusions:

• Laser pulse polarization critically affects supercontinuum generation efficiency in air.
• Circular polarization offers superior conversion efficiency for white light generation via filamentation.
• Findings are relevant for applications requiring efficient long-distance nonlinear light generation in the atmosphere.