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Part 1 : Nanoparticles

Module 3 : Dielectric properties of materials

Lecture 4 : Multiple oscillator model for Lattice vibrations

Consider now the special case where $\vec q$ is along one of the principal axes, say, the

-axis. Then if

is referred to principal axis, these equations reduce to

and

If $\epsilon_3\ne 0$ , then $E_{oz}=0$ , i.e., the wave is transverse, the remaining component having the solutions,

so that the plane wave can propagate along the

-axis without a change in polarization if they are either

-polarized or

-polarized. The complex refractive indices for these two types of waves are different