Refractive Index of Calcium Oxide

A method is described which has been successfully used to produce single crystals of calcium oxide of excellent optical quality from the melt. The absolute refractive index of two of these crystals was determined by the method of minimum deviation at room temperature (22°–26°C) for six wavelengths in the visible spectrum. The observed values for one of the crystals varied from 1.8328±5×10−5 at the wavelength 6562.82 Å to 1.8702±5×10−5 for the Hg line at 4358.35 Å. The corresponding values at these wavelengths for the other specimen were 1.8335±6×10−5 and 1.8708±6×10−5, respectively.