Indicatrix Fletcher

The Fletcher indicatrix was deduced from equation (4.98). In an analogous manner, we can obtain from equation (4.99) an ellipsoid which represents the tensor s and hence the rates v... 

The ellipsoid n xl + n xl -h = 1, called the rate ellipsoid, has the property that the length of the ray parallel to E is r = v /Vo-The Fletcher indicatrix allows the determination of the polarizations and refractive indices of the waves which propagate in a crystal along the normal v. The intersection of the ellipsoid and the plane perpendicular to v which passes through the center is an ellipse. The vector D normal to v lies in this plane. 

Construction permitting the derivation of the two waves associated with a normal v by means of the Fletcher indicatrix (Fig, 4,22) ... 

---