100 W orbital angular momentum laser at 2 µm.

Area of Science:

• Laser Physics
• Photonics
• Materials Science

Background:

• Orbital Angular Momentum (OAM) lasers offer unique structured light properties.
• Direct power scaling of OAM lasers remains a significant challenge.
• Ho:YAG single-crystal fibers (SCF) possess advantageous thermal and optical properties for high-power applications.

Purpose of the Study:

• To demonstrate direct power scaling of an at-source scalar orbital angular momentum (OAM) laser.
• To investigate the potential of Ho:YAG SCF for generating high-power OAM beams.
• To achieve record power levels for OAM lasers in the 2 µm spectral range.

Main Methods:

• Utilized a Ho:YAG single-crystal fiber (SCF) laser architecture.
• Leveraged the long gain region and high surface-to-volume ratio of the SCF.
• Employed direct power scaling techniques for OAM beam generation.

Main Results:

• Achieved a 100 W optical vortex laser with OAM = ℏ.
• Obtained a high slope efficiency of 66.0% at 2.1 µm.
• Demonstrated the highest power for an at-source OAM laser in the 2 µm range to date.

Conclusions:

• Direct power scaling of OAM lasers is feasible using Ho:YAG SCF.
• Ho:YAG SCF enables efficient generation of high-power structured light.
• This work establishes a new method for producing high-power, high-efficiency OAM laser beams.