Tunable, high-power, high-order optical vortex beam generation in the mid-infrared

Area of Science:

• Nonlinear Optics
• Quantum Optics
• Laser Physics

Background:

• Optical vortices, characterized by helical phase fronts, are crucial for advanced optical applications.
• Generating tunable, high-order optical vortices in the mid-infrared (mid-IR) presents significant challenges.

Purpose of the Study:

• To demonstrate the generation of tunable high-order optical vortices in the mid-IR using a picosecond optical parametric oscillator (OPO).
• To achieve direct transfer of pump optical vortices to the idler beam of the OPO.

Main Methods:

• Utilized a singly-resonant OPO based on MgO:PPLN nonlinear crystal.
• Synchronously pumped the OPO with a mode-locked Yb-fiber laser at 1064 nm.
• Employed pump optical vortices with topological charges from l=1 to l=5.

Main Results:

• Successfully generated tunable optical vortices in the idler beam of the OPO across the mid-IR (2538 nm to 4035 nm).
• Achieved direct transfer of pump vortex orders (l=1 to 5) to the idler beam.
• Obtained output powers ranging from 630 mW down to 130 mW for the highest idler vortex order (l=5).

Conclusions:

• This work presents the first report of an OPO pumped by a high-order vortex beam (l=5) generating mid-IR idler vortices.
• The developed method offers a novel route for generating tunable, high-order optical vortices in the mid-IR spectrum.
• This advancement opens possibilities for novel applications in mid-IR spectroscopy, imaging, and optical manipulation.