Design of IR Laser Windows for Cryogenic Lasers
Special technical rept.
NORTHROP RESEARCH AND TECHNOLOGY CENTER PALOS VERDES PENINSULA CA
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The first part of the report derives expressions for thermal stresses in IR laser windows subjected to uniform cooling. It is shown that the radial contraction effects produce negligible stresses in the window. Fracture of the window is caused by highly localized shear stresses due to axial contraction of the window. A nondimensional plot is given for the determination of the maximum interface shear stress. The second part of the report summarizes the results of CaF2 window cool-down experiments. The results indicate that at least two types of adhesives are suitable for use in cryogenic window assemblies. Based on the above results, CaF2 laser window assemblies have been designed for use in cryogenic CO electric discharge lasers. These windows have been subjected to thermal cycling between room and LN2 77K temperatures over the past two years with satisfactory performance.
- Lasers and Masers