The Research Of Intra-cavity Beam Cleanup Of Diode Pumped Solide State Laser

Intra-cavity beam cleanup is an important technique to achieve high averagepower, high beam quality and high efficiency all solid-state laser output. Howevertheoretical research about intra-cavity beam cleanup is involved little. With regard tothis problem, a series of study is carried on in this paper. Using fox-li iterative methodto the parameters of deformable mirror used in intra-cavity beam cleanup is clarified.In this paper, a simulating model of intra-cavity beam cleanup is founded. Thenumerical results settle foundation for further study of intra-cavity beam cleanup. Andan experiment study testified validity of this simulating model.First, this paper discussed how distortions affect the output beam quality anddiffraction loss of cavity. The distortions are decomposed by a series of Zernikepolynomials with weighting factors. The diffraction loss and beam quality ofaberrated cavity with Zernike distortion are calculated though fox-li, by changing onlyon value of weighting factors, and the other weighting factors are equal to zero.Numerical analysis results show that in order to get diffraction limited beam quality,the peak-to-valley (PV) of aberration should be less than λ/10.Second, a simulating model about intra-cavity beam cleanup is founded base onFox-li iterative method. The simulation results show that the output beam qualityapproaches ideal parameter as iterations of SPGD algorithm increased.At last, a test system experiment of intra-cavity beam cleanup system wasbuilded, and a lot experiments are tested under a diode pumped rod Nd:YAG laser.The beam quality M2of ideal TEM00is equal to1. The initializing beam quality M2isequal to1.92, and beam quality M2is reduced to1.22after beam cleanup. Thisexperiment result shows that laser beam is closer to ideal beam. The results ofexperimental data and numerical simulation model comparison show that thesimulation model can reflect the physical process of intracavity beam cleanup.