Photopolymerization with high-order Bessel light beams.

Area of Science:

• Optics and Photonics
• Materials Science
• Polymer Chemistry

Background:

• Bessel light beams are known for their propagation-invariant properties.
• Photopolymerization is a light-induced polymerization process used in material fabrication.
• Phase singularities in light beams can impart unique properties to light-matter interactions.

Purpose of the Study:

• To investigate the fabrication of extended helical microfibers using high-order Bessel light beams with on-axis phase singularities.
• To understand the self-trapping and self-focusing dynamics of these light beams in photopolymers.
• To explore the relationship between optical power and the growth and rotation of the resulting microstructures.

Main Methods:

• Utilizing high-order Bessel light beams with on-axis phase singularities for photopolymerization.
• Employing self-trapping and self-focusing phenomena of propagation-invariant beams.
• Analyzing the evolution, rotation, and structural periodicity of fabricated microfibers as a function of incident optical power.

Main Results:

• Successful fabrication of centimeter-scale extended helical microfibers, significantly exceeding the Bessel beam's propagation distance.
• Observed microfiber rotation rate proportional to incident optical power.
• Demonstrated constant periodicity of helical structures regardless of laser power.

Conclusions:

• Optical momentum transfer is the predominant mechanism driving the growth and rotation of these helical microfiber structures.
• High-order Bessel beams with phase singularities offer a novel route for creating extended, complex microstructures.
• The findings suggest potential applications in micro-optics, micro-robotics, and advanced material design.