Texture effect of hot-pressed magnesium fluoride on optical transmittance

This paper presents the results of a study on the optical transmittance of hot-pressed magnesium fluoride dome and disk blanks in terms of the optical anisotropy caused by the material texture. The issues involving the hot-pressing dome texture are discussed using the X-ray diffraction pattern method. It is shown that the texture is produced by the magnesium fluoride compaction during the hot-pressing process due to the plastic flow in the individual micrograins. Further details on the textural features of hot-pressed magnesium fluoride dome sample can also be obtained using the interference polarization pattern method. A comparison of the transmittance in the two principal directions in a hot-pressed disk sample strongly suggested that a reduction in the birefringent scattering loss resulting from the optical anisotropy is mainly responsible for the high transmittance.