Chinese Journal of Lasers, Volume. 35, Issue 8, 1240(2008)
Design and Fabrication of Graded Reflectivity Mirrors
According to the parameter requirement of the graded reflectivity mirror (GRM) with Gaussian profile, the layer structure and the mask pattern were designed by using graded-thickness middle layer. The mask and the mask switchover equipment were designed considering the actual requirement of the thin films and the specific deposit facility. All layers of the graded reflectivity mirror were deposited in one high vacuum environment. Using a direct measuring method, the radial reflectivity distribution of graded reflectivity mirror with Gaussian profile was measured. The measuring results indicate that the graded reflectivity mirror with Gaussian profile prepared with this technique is basically in accordance with the design requirement. Analysis indicates that the mask pattern and accuracy influence the deposit result. The scattering effect of the mask on the material molecules increases with the decrease of the design dimension, the center reflectivity of the sample becomes lower than the design requirement, and the side lobe arises at the edge of the sample. The improving methods are proposed as decreasing the distance between the substrate and the mask, and increasing the monitor accuracy of the layer thickness.
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Lü Guonuan, Li Dawei, Huang Jianbing, Yi Kui. Design and Fabrication of Graded Reflectivity Mirrors[J]. Chinese Journal of Lasers, 2008, 35(8): 1240