Space-time couplings in ultrashort lasers with arbitrary nonparaxial focusing

Area of Science:

• Optics and Photonics
• Ultrafast Laser Science
• Electromagnetic Theory

Background:

• Space-time separability is a common assumption in laser beam theory.
• Ultrashort laser pulses often exhibit spatio-temporal effects, altering their spatial and temporal properties.
• These effects become significant in tightly focused configurations.

Purpose of the Study:

• To investigate spatio-temporal effects in tightly focused laser beams.
• To analyze the modification of the TM01 beam mode at focus.
• To compare semi-analytical and numerical diffraction integral models.

Main Methods:

• Development of semi-analytical diffraction integral models.
• Development of numerical diffraction integral models.
• Investigation of chromatic angular dispersion, curvature, and spatial chirp effects on the TM01 mode.

Main Results:

• Demonstration of spatio-temporal effects in focused ultrashort laser pulses.
• Quantification of the impact of chromatic angular dispersion, curvature, and spatial chirp on the TM01 mode.
• Validation of the developed models through comparison.

Conclusions:

• The assumption of space-time separability is not always valid for ultrashort laser pulses.
• The developed models provide a toolset for analyzing extreme space-time localization of structured electromagnetic beams.
• This research advances the understanding and modeling of complex laser beam behavior.