Optical fused quartz and fused silica for high-energy lasers

TheNIP and LMJ programs will require large rectangular laserglass slabsof unprecedented magnitude, in terms of size and quantity. Several methods exist formelting glass, but to effectively melt a large volume with production ease, while maintaining low cost and consistent quality, the best method is continuous melting. The phosphate type laser glass to be produced must be of high precision, in addition to homogeneous and having stringentspecs for bubbles, indusiors, water content and other impurities which can adversely influence laser performance. As a Fe-melt for the forthcoming full production, we have performed continuous melting demonstratior running tests using a sub-scale furnace. Jn this system, not only is the melting technique important, but the forming of the extruded bar (instead of the traditional casting blocks) is very important for the completion of the total melting system. Melting of laser glass in a continuous fashion has not previously been achieved worldwide until now. Herein, we briefly present our concept of the system and the quality of the Iass material produced, alone a summary of the achievements from our development work.