Study Of Damage Characteristics Of Anti-reflection Fused Silica By Long Pulse Laser

With the development of laser technology,the indicators of the optical element requirement gradually improve,where laser damage resistance is one of the very important indicators.With the characteristic of large single pulse energy and damage ability compared with the short pulse laser,long pulse laser can cause more serious damage to target.The damage characteristics,temperature field and stress field of anti-reflection fused quartz under the irradiation of the long pulse laser were theoretical and experimental investigated in this paper.Based on heat transfer theory,elasto-plastic constitutive theory and finite element method,the physical process of anti-reflection fused quartz irradiated by a single pulse and multi-pulse were analyzed.Through calculation of the heat conduction theory and elasto-plastic constitutive theory,the material of the transient distribution and evolvement of thermal and stress with the space and time was obtained.The maximum density of the central point is about 1360 K when the bulk density is 3185 J / cm2,At the same time,the temperature and stress changes of changing a single parameter were obtained.Central point temperature of anti-reflection fused quartz induced by long pulse laser was measured experimentally.On the theory of the Mach-Zehnder interferometer(MZI),a long pulse laser irradiation anti-reflection fused quartz online stress measurement experimental system was set up,obtaining the change of the interference fringes of the fused quartz produced by stress.Through the relationship between stress and strain and the principle of interference on the interference fringes change,the fused quartz online real-time change of stress was obtained,When the energy density is 1943 J / cm2,the maximum value of ?x is 17.97 MPa and ?z is 4.8MPaThen the residual stress inside the material,damage morphology after laser irradiation and growth law of damage area were discussed,the law and characteristics of laser damage anti-reflection fused quartz was summarized.