Method to improve beam quality by compensating spherical aberrations in master oscillator power amplifier laser...

Area of Science:

• Optics and Photonics
• Laser Physics
• Wavefront Engineering

Background:

• Master oscillator power amplifier (MOPA) laser systems are crucial for high-power applications.
• Beam wavefront evolution, including spherical aberration, significantly impacts laser beam quality.
• Understanding and controlling spherical aberration is key to improving laser performance.

Purpose of the Study:

• To develop and demonstrate a method for improving beam quality in MOPA laser systems.
• To investigate the dynamics of spherical aberration during laser beam propagation.
• To achieve significant improvements in laser beam quality and output power.

Main Methods:

• Intensive study of beam wavefront evolution within a laser resonator and free space propagation.
• Analysis of spherical aberration coefficient sign changes during beam propagation.
• Compensation of negative spherical aberration from the oscillator using positive spherical aberration from a pumped laser amplifier rod.

Main Results:

• Demonstrated that spherical aberration can change sign during laser beam propagation.
• Successfully compensated for negative spherical aberration from the oscillator with the amplifier's positive spherical aberration.
• Significantly improved laser beam quality, with the M² factor reducing from 2.2 to 1.4.
• Increased laser output power from 31 W to 60 W.

Conclusions:

• The proposed method effectively improves laser beam quality in MOPA systems.
• Controlling spherical aberration through component design is a viable strategy for laser performance enhancement.
• This technique offers a pathway to higher power and better quality laser beams for various applications.