11 September 1989 Comparison Of Large ALON And Sapphire Windows
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ALON (aluminum oxynitride) and sapphire windows measuring approximately 10 x 4 inches have been produced. Transmittance and mechanical durability in an extreme operational environment are essential for these windows. ALON is produced by ceramic powder processing techniques, while sapphire is grown as a single crystal. The ALON blank fabrication has been scaled up at Raytheon to produce several windows. Near net shape blanks were successfully polished to demanding optical and dimensional specifications at Zygo. Wavefront distortion and an atypical scattering phenomenon in large ALON windows are discussed. Sapphire windows were fabricated from plates cut from 10-inch diameter single crystal boules, using optical fabrication procedures similar to those developed for the ALON windows. The relative cost of optical fabrication of the two materials is discussed. Optical and mechanical properties for ALON and sapphire windows are presented.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Richard Gentilman, Edward Maguire, Theodore Kohane, David B. Valentine, "Comparison Of Large ALON And Sapphire Windows", Proc. SPIE 1112, Window and Dome Technologies and Materials, (11 September 1989); doi: 10.1117/12.960761; https://doi.org/10.1117/12.960761


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