The demand for large ALON~? windows has continued to increase since the material transitioned to Surmet Corporation for commercialization. Two applications which represent opposite ends of the requirements spectrum in terms of required optical performance and cost sensitivity are Reconnaissance windows and transparent armor. Consequently, the approaches to producing large area windows for both applications are quite different. While Recce applications require windows of the highest possible optical quality and stringent refractive index homogeneity across the large aperture sizes of Recce sensors, the optical requirements for transparent armor windows are substantially looser. Furthermore, optical performance is paramount for Recce applications while transparent armor applications are more strongly driven by cost considerations. Surmet has developed processes for producing large (i.e., up to ～17×30-in) ALON~? window blanks of extremely high optical quality and refractive index homogeneity, for Recce applications. This material has been optically fabricated into finished windows and characterized for transmitted wavefront and homogeneity. Recent results will be presented. Large area transparent armor windows have been produced using a tiling approach. Since transparent armor laminates consist of multiple layers (i.e., ALON/Glass/Polycarbonate) Smaller ALON~? tiles can be face bonded onto the underlying glass and polycarbonate layers to produce very large windows. Excellent ballistic results have been obtained using a tiled configuration. Recent results will be presented.
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