Past exam of the optics and electrodynamics course of the University of Cambridge / 2016 / Paper 1 / 4 / b / Solution

Now $\mathbf{u}\cdot \mathbf{e}=u_y=\sin \theta \sin \varphi$, soWhenever nonzero, the scattered light has the same linear polarization along $\mathbf{v}$ as in (a). Although the incident field points toward the observer, the tilted anisotropic needle can induce a dipole component perpendicular to that direction. An isotropic sphere would instead have an axial radiation zero for this incident polarization.