The electrodichroic ratio qro for suspensions of absorbing spheroids has been calculated using dipolar light scattering theory. This theory predicts, in accordance with experimental observations on Varad suspensions, that the transmission will usually be higher when the particles are aligned nose-on in the incident beam than in the random state. The effect of complex refractive index and of the axial ratio of the spheroids upon qro is discussed in some detail. It appears that metals having the refractive properties of aluminum offer the best possibility for preparing optical windows from these suspensions.
M. Kerker and D. D. Cooke, "Electrooptic Properties of Absorbing Spheroids," Appl. Opt. 10, 2670-2674 (1971)