Hybrid stable-unstable resonators for diffusion-cooled CO(2) slab lasers

Area of Science:

• Laser Physics
• Optical Engineering

Background:

• Diffusion-cooled carbon dioxide (CO2) slab lasers offer efficient gas laser operation.
• Hybrid stable-unstable resonators are crucial for optimizing laser performance and beam quality.

Purpose of the Study:

• To numerically and experimentally compare the performance of two hybrid stable-unstable resonators for CO2 slab lasers.
• To evaluate resonators with positive- and negative-branch unstable schemes within a specific rf-discharge channel.

Main Methods:

• Numerical simulations and experimental characterization of resonator performance.
• Analysis of modal structure, power extraction efficiency, resonator stability, and output beam quality.
• Design and implementation of resonators for a 320 mm × 60 mm ×2 mm rf-discharge channel.

Main Results:

• The negative-branch unstable resonator scheme exhibited higher power extraction efficiency.
• The negative-branch resonator also provided a higher quality extracted beam compared to the positive-branch scheme.
• Both resonator designs were stable and guided within the narrow transverse direction of the slab laser.

Conclusions:

• The negative-branch hybrid stable-unstable resonator is a more effective design for diffusion-cooled CO2 slab lasers.
• This study provides valuable insights for the design and optimization of high-power gas lasers.
• Further research could explore variations in resonator geometry and discharge parameters.