Multilevel synergically controlling wavefront correction of a high-power slab laser system

Area of Science:

• Optics and Photonics
• Laser Physics
• Wavefront Engineering

Background:

• Slab geometry solid-state lasers exhibit complex wavefront aberrations, including fourth-order and longitudinally distributed aberrations (e.g., Legendre polynomials).
• Single deformable mirrors (DM) have limitations in response frequency and actuator stroke, necessitating pre-compensation strategies.
• Coupling oscillations can occur between pre-compensating levels and adaptive optics (AO) due to diverse device bandwidths.

Purpose of the Study:

• To present a novel multilevel synergically controlling wavefront correction method for slab laser systems.
• To enhance the utilization of deformable mirror (DM) actuator response frequency and stroke.
• To mitigate wavefront aberrations in slab lasers, thereby improving beam quality.

Main Methods:

• Designed a multilevel wavefront correction system to reduce root-mean-square wavefront aberration before the DM.
• Integrated a pre-compensating level comprising a slow-drift mirror, fast-steer mirror, one-dimensional adjustable slab-aberration compensator, and beam-shaping system.
• Developed a multilevel synergic control strategy to address coupling oscillations between pre-compensating and AO levels.

Main Results:

• Effectively reduced specific orders of wavefront aberration (5th, 9th, 14th Legendre polynomials) with low spatial resolution and large stroke.
• Demonstrated successful compensation of residual wavefront aberration by the AO level within its capabilities.
• Cleaned up a 9.8 kW slab laser system, improving beam quality (β) from 17.71 to 2.24 times the diffraction limit.

Conclusions:

• The multilevel synergic control method effectively compensates for wavefront aberrations in slab lasers.
• The pre-compensating level significantly enhances the performance of the adaptive optics level.
• This technique offers a viable solution for improving the beam quality of high-power slab laser systems.