Before revision: In crystal optics, the index ellipsoid (also known as the optical indicatrixBorn & Wolf, 2002, p. 799; Yariv & Yeh, 1984, p. 77. or sometimes as the dielectric ellipsoidJenkins & White, 1976, pp. 560–61.)
After revision: In crystal optics, the index ellipsoid (also known as the optical matrixBorn & Wolf, 2002, p. 799; Yariv & Yeh, 1984, p. 77. or sometimes as the dielectric ellipsoidJenkins & White, 1976, pp. 560–61.)