Optimization of beam intensity distributions with intracavity bimorph deformable mirror

An intracavity adaptive optics system is presented for optimizing beam intensity profiles of an flashlamp-pumped Nd:YAG laser. The rear mirror of the laser is replaced by a 20-element bimorph deformable mirror controlled by a stochastic parallel gradient decent algorithm aiming at achieving more concentrated power distribution in the far-field. Experimental results demonstrate that this system effectively transforms the far-field intensity distribution with multiple lobes into a single bright lobe within only about 20 s, and the peak intensity is improved up to 6 times. The output power can be increased from 0.006-0.051 W to 0.330 W when large misalignment exists. The effectiveness of the proposed system is demonstrated by the above experimental results.