Scaling the spectral beam combining channels in a multiplexed volume Bragg grating

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• High-power laser systems often require combining multiple laser beams.
• Traditional beam combining methods can be complex and bulky.
• Volume Bragg gratings (VBGs) offer a promising approach for efficient spectral beam combining.

Purpose of the Study:

• To present recent advances in high-power spectral beam combining using multiplexed VBGs.
• To demonstrate a simplified combining system by recording multiple gratings in a single photo-thermo-refractive (PTR) glass substrate.
• To explore the scalability of this technique for future high-power laser applications.

Main Methods:

• Recording of multiplexed volume Bragg gratings within a single piece of photo-thermo-refractive (PTR) glass.
• Utilizing monolithic, multiplexed gratings (double and quadruple) for spectral beam combining.
• Characterization of combining efficiency and beam quality.

Main Results:

• Demonstrated combining of 420 W of laser power with 96% efficiency using a monolithic, multiplexed double grating.
• Successfully demonstrated a multiplexed quadruple grating maintaining high efficiency and good beam quality.
• The use of multiplexed gratings within a single PTR glass block significantly lowers system complexity.

Conclusions:

• Multiplexed volume Bragg gratings recorded in PTR glass enable high-efficiency spectral beam combining of high-power lasers.
• This approach offers a simplified and scalable solution for combining multiple laser channels.
• The demonstrated quadruple grating paves the way for further scaling of combining channels in future laser systems.