Casting of Halide and Fluoride Alloys for Laser Windows
Semiannual technical rept. no. 2
RAYTHEON CO WALTHAM MA RESEARCH DIV
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The main objective of this program is to demonstrate the feasibility of fusion casting of alkali halides and alkaline earth fluorides for high power laser window applications. The main effort deals with the fabrication and property evaluation of the alkaline earth fluorides. During the second six months of this program high quality castings of both CaF2 and SrF2 were fabricated. Castings of CaF2 were attempted in an inert atmosphere of purified argon 1-50 torr. Calorimetrically measured 5.25 micrometer bulk absorption coefficients for cast CaF2 are being consistently attained near 0.00042cm regardless of the starting material. In preliminary results the 5.25 micrometer bulk absorption coefficient of cast SrF2 lies near 0.000067cm for an ingot using single crystal chips as starting material and lies near 0.00017cm for an ingot cast from purified reagent grade powder. The preliminary results also show that SrF2 is equivalent in strength to CaF2 and that polycrystalline cast material is equivalent in strength to single crystal material.
- Lasers and Masers