High temperature thermal behaviour modeling of large-scale fused silica optics for laser facility

High temperature annealing is often used for the stress control of optical materials.However,weight and viscosity at high temperature may destroy the surface morphology,especially for the large-scale,thin and heavy optics used for large laser facilities.It is necessary to understand the thermal beha...

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Published inChinese physics B Vol. 21; no. 6; pp. 329 - 334
Main Author 于景侠 贺少勃 向霞 袁晓东 郑万国 吕海兵 祖小涛
Format Journal Article
LanguageEnglish
Published 01.06.2012
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Summary:High temperature annealing is often used for the stress control of optical materials.However,weight and viscosity at high temperature may destroy the surface morphology,especially for the large-scale,thin and heavy optics used for large laser facilities.It is necessary to understand the thermal behaviour and design proper support systems for large-scale optics at high temperature.In this work,three support systems for fused silica optics are designed and simulated with the finite element method.After the analysis of the thermal behaviours of different support systems,some advantages and disadvantages can be revealed.The results show that the support with the optical surface vertical is optimal because both pollution and deformation of optics could be well controlled during annealing at high temperature.Annealing process of the optics irradiated by CO2 laser is also simulated.It can be concluded that high temperature annealing can effectively reduce the residual stress.However,the effects of annealing on surface morphology of the optics are complex.Annealing creep is closely related to the residual stress and strain distribution.In the region with large residual stress,the creep is too large and probably increases the deformation gradient which may affect the laser beam propagation.
Bibliography:Yu Jing-Xia ,He Shao-Bo ,Xiang Xia ,Yuan Xiao-Dong,Zheng Wan-Guo ,Lü Hai-Bing ,and Zu Xiao-Tao ( a)Department of Applied Physics,University of Electronic Science and Technology of China,Chengdu 610054,China b)Research Centre of Laser Fusion,China Academy of Engineering Physics,Mianyang 621900,China
numerical simulation, support systems, large-scale fused silica, high temperature
11-5639/O4
High temperature annealing is often used for the stress control of optical materials.However,weight and viscosity at high temperature may destroy the surface morphology,especially for the large-scale,thin and heavy optics used for large laser facilities.It is necessary to understand the thermal behaviour and design proper support systems for large-scale optics at high temperature.In this work,three support systems for fused silica optics are designed and simulated with the finite element method.After the analysis of the thermal behaviours of different support systems,some advantages and disadvantages can be revealed.The results show that the support with the optical surface vertical is optimal because both pollution and deformation of optics could be well controlled during annealing at high temperature.Annealing process of the optics irradiated by CO2 laser is also simulated.It can be concluded that high temperature annealing can effectively reduce the residual stress.However,the effects of annealing on surface morphology of the optics are complex.Annealing creep is closely related to the residual stress and strain distribution.In the region with large residual stress,the creep is too large and probably increases the deformation gradient which may affect the laser beam propagation.
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1674-1056
2058-3834
1741-4199
DOI:10.1088/1674-1056/21/6/064401