Lasing and waveguiding in smectic A liquid crystal optical fibers

Area of Science:

• Soft matter physics
• Materials science
• Photonics

Background:

• Liquid crystals offer unique optical properties.
• Microstructured fibers are essential for advanced optical applications.
• Topological defects can influence light propagation.

Purpose of the Study:

• To demonstrate a new class of soft matter optical fibers based on smectic-A liquid crystals.
• To investigate the optical properties and light guiding capabilities of these fibers.
• To explore the potential for Whispering Gallery Mode (WGM) lasing and applications in soft photonic circuits.

Main Methods:

• Self-assembly of smectic-A liquid crystal microtubes in aqueous surfactant dispersions.
• Characterization of fiber uniformity, birefringence, and topological defects.
• Demonstration of light guiding and WGM lasing using polarized excitation beams.
• Manipulation of fibers using laser tweezers.

Main Results:

• Uniform diameter and high birefringence of the liquid crystal fibers.
• Observation of a line topological defect with specific optical axis orientation.
• Successful light guiding and WGM lasing, with polarization-dependent thresholds.
• Very low WGM lasing threshold (≈ 75μJ/cm²) under optimal polarization conditions.
• Demonstrated flexibility and manipulability of the fibers.

Conclusions:

• Smectic-A liquid crystal microtubes represent a new class of soft optical fibers.
• These fibers exhibit promising light guiding and low-threshold lasing properties.
• The flexibility and controllability suggest potential for developing soft photonic circuits.