The Design And Experimental Research On High Stable Output Power,High Beam Quality Of Ultrashort Pulse Laser

LD pumped solid state laser has many advantages,such as small volume,light weight,high efficiency,reliable performance and low price.With the popularization of ultrashort pulse laser in laser processing and laser measurement,it is necessary to improve the performance index of laser power,beam quality and so on.The resonator is one of the most important components of the laser,the quality of the laser beam quality and output power stability and other important performance parameters,to a large extent depends on the design quality of the laser resonator.In the ultrashort pulse solid laser,in order to achieve stable mode locking,people often use the curved mirror to focus the beam onto a clamping device to obtain a strong laser energy density bleaching saturable absorber;on the other hand,in order to reduce the volume of laser and intracavity dispersion,often using a mirror to the light path folding.However,when a curved mirror is used as a folding mirror in the resonant cavity,the laser beam is tilted to the surface of the mirror,will have astigmatism.Because of the uneven distribution of the inner heat and the elastic strain of the laser working substance,the refractive index of the solid laser can be changed.In high power laser or pulsed laser cavity high power laser system,the gain medium thermal lens focal length fluctuations,will cause changes in cavity spot radius,which leads to a decline in the stability of laser output power,and even cause the deterioration of beam quality.In order to obtain high stable output power and high beam quality,it is necessary to study the above two problems.This paper mainly makes a theoretical and experimental study for astigmatic compensation of laser resonant cavity,in order to obtain the laser output with high beam quality;on the other hand,carried out theoretical and experimental research on the influence of thermal lens on the laser output power and ultrashort pulse laser in order to obtain high stability output power.In this paper,main work is as follows:1)proposed a laser resonant cavity design method of circular double arm astigmatic compensation based on the transmission circle and transform circle.The method is simple and intuitive,without complex formulas and complicated computing process,only need to use a simple relationship between the object can complete the laser resonator design work,and obtain the parameters of resonant cavity.2)Study on the thermal stability of laser cavity,in the theory of transmission circle and transform circle,this paper proposes a method of double arm astigmatism compensation at the same time not sensitive to the thermal lens resonator,the theoretical and experimental results show that the method can be used to design high stability output power and high beam quality laser cavity.