The Research On Characteristics Of The High Power Diode End-pumped Slab Laser Amplifierre

The diode end-pumped slab laser amplifier, one of the area of solid-state-lasers,has been widely used in many areas including national defense, industry, medicaltreatment and scientific research. Due to its outstanding advantage in high output power,it is a hot topic in the research world. To gain a laser beam with high output power andgood quality is the main goal to the scientists. The research in slab laser amplifier underhigh power diode pumped has the practical meaning.In this paper, we theoretically analy the physical and mechanical features ofNd:YAG crystal as the slab laser amplifier gain model, the formula of steadily output inslab laser amplifier under the Zig-zag laser path. The angle of incidence selected byusing geometrical optics method, in this way it could avoid light splitting caused byarbitrary angle. Given the definition of beam filling factor, which is a very importantparameter related to output power and extraction efficiency and which have beencalculated under the different conditions of incidence angle and cut angle. The gaincoefficient of the energy storage has been completed by theoretical analysis. Themeasured small signal gain coefficient is consistent with the calculated results.Gain module is one of the most important part of the laser amplifier. To understandthe laser amplifier’s performance, we do a research on the projection wavefrontdistortion under high power condition. We obtain the phase wavefront information byusing the Shark-Hartmann method. A piece of slab gain module with small staticwavefront distortion of PV value has been selected in our experiment. When the pumpis5700W,with or without the signal laser injection the value of transmitted wavefrontdistortion is3.49or3.41μm respectively.We have simulated the effect of output power under different incident angle,injection power density and beam size and the influence of input power density on theextraction efficiency of energy in high power diode pumped condition. According to thetheoretical analysis, experimental light path of amplifier has been built, the optimalincident angle and beam size have been selected and the amplifier output power and thelaser wavefront distortion have been measured. The output power is10810W with injection sigal laser of8900W and the wavefront distortion value is3.37μm.Theduration time is67s when the ouput power is stead and the average value of beamquality β is9.06times the diffraction limit.