Pulsed Optical Vortex Array Generation in a Self-Q-Switched Tm:YALO₃ Laser.

Area of Science:

• Optics and Photonics
• Laser Physics

Background:

• Optical vortex arrays possess unique orbital angular momentum properties, crucial for applications like optical trapping, communication, and information processing.
• The 2 μm wavelength is significant for laser medicine, sensing, and nonlinear optics, yet 2 μm pulsed vortex sources are underdeveloped.

Purpose of the Study:

• To demonstrate a compact, self-Q-switched laser generating 2 μm pulsed optical vortex arrays.
• To explore the potential of combining 2 μm pulsed laser advantages with optical vortex array capabilities.

Main Methods:

• Utilized a Tm:YALO3 crystal and a defect spot mirror within a compact laser cavity.
• Employed self-modulation effects and tuning of the defect spot and output coupler to control vortex generation.
• Generated optical vortex arrays with phase singularities ranging from 1 to 4.

Main Results:

• Achieved a compact self-Q-switched Tm:YALO3 vortex laser operating at 2 μm.
• Successfully generated optical vortex arrays with 1 to 4 phase singularities.
• Recorded narrowest pulse widths for various vortex configurations, including TEM00 LG0,-1 (543 ns) and four-vortex arrays (1615 ns).
• Demonstrated high-power output, slope efficiencies, and single-pulse energies for all generated vortex arrays.

Conclusions:

• This work presents a novel 2 μm pulsed structured light source.
• The compact vortex laser offers potential applications in optical manipulation, free-space optical communications, and laser medicine.