Study On Methods Of Controlling Thermal Lens Of Laser Crystal

High power output of DPL is an important development direction. But the thermaleffect of a laser crysta l is an important factor to limit the improvement of laser power. Inthis paper, with laser crysta l made of Nd:YAG as the object of research, two newmethods for abating the laser thermal effect will be put forward and discussed. Thispaper will also discuss the advantages of them over traditiona l methods throughnumerica l calculation.First of all, this paper will raise a method based on radia l gradient intermingling forabating nonidea l part of the laser thermal lens. Because of the difference between theintensity distribution of TEM00 and that of other modes, this paper will propose a pointthat the gradient intermingling of the laser crysta l should be designed following therules that distribution of heat consumption should be even in the range of the radius ofTEM00, so that the nonidea l part of the laser thermal lens can be abated. This paper willalso discuss whether or not this design still have the advantages over traditiona l eveninterminglingdesign as the intensity distribution of pumping light is not exactly therating distribution, and the conclusion is that the design of the gradient intermi- nglingin in the condition of Gaussia n-beam pumping still has the advantages, but that of pla netop-light pumping does not.Second of all, this paper will raise a method based on nonspherical end-face lappingfor counteracting laser thermal lens. This method is a innovation of the traditiona lmethod of spherical end-face lapping, in order to counteract thermal-lens effect more precisely.A comparation between the function of this new method and that of thetraditiona l method will be discussed so that we can see the advantage of the new method,and the conclusion is that the design of shape of the end-face lapping according to theintensity distribution of pumping light is much more effective in abating the thermaleffect of laser crysta l tha n the traditiona l method of spherical end-face lapping.At last, I hope this paper can provide two possible direction of the study aboutimprove the output beam quality of high-power laser.