We investigate theoretically the optical properties of Nano-Wires (NWs) with
cross sections having either discrete or cylindrical symmetry. The material
forming the wire is birefringent, showing a different dielectric response in
the plane and along the axis of the wire, which is typically the case for wires
made of wurtzite materials, such as ZnO or GaN. We look for solutions of
Maxwell`s equations having the proper symmetry. The dispersions and the
linewidths versus angle of incident light for the modes having high momentum in
the cross-section plane, so called whispering gallery modes, are calculated. We
put a special emphasis on the case of hexagonal cross sections. The energy
positions of the modes for a set of azimuthal quantum numbers are shown. We
demonstrate the dependence of the energy splitting between TE and TM modes
versus birefringence. The polarization conversion from TE to TM with increase
of the axial wave vectoris discussed for both cylindrical and discrete
symmetry.Comment: 9 pages, 10 figure