Low Cost Polycrystalline YAG for Low-Distortion, Abrasion-Resistant, High-Strength IR Windows

We propose to demonstrate that polycrystalline YAG is an ideal material of choice for High Energy Laser Windows mounted in pressure bulkheads. We will demonstrate that dense polycrystalline YAG can be fabricated at low cost and that this material is fullytransparent with very low absorption and scatter characteristics at the laser wavelengths. Further we will demonstrate that dense polycrystalline YAG, which has lensing figure-of-demerit similar to low OPD glasses and fused silica, can be made to have farsuperior strength and stability with excellent resistance to abrasion, all of which are important for laser window applications. We expect that the low-cost dense polycrystalline YAG we develop will be used in many, if not all, applications that requirelaser and IR windows with minimal distortion, high abrasion resistance, high mechanical strength and extraordinary environmental stability. If successful, the technology could be transitioned immediately to one or more advanced DE weapon insertions ofdirect interest to the Air Force. Commercial benefits include improved competitive opportunities for providers of aerospace windows. These window materials would find commercial use in visual and IR transparencies for aircraft and launch vehicles, chemicalprocessing windows, and high energy lighting element holders. This material is also likely to find application in several commercial areas such as in precision laser machining/welding.