Elliptical polarization from circular and linear components
= Elliptical polarization from circular and linear components
Two coherent waves with common propagation direction and <frequency> can combine into a <polarization ellipse>. Take circular components $E_x=A\cos\psi$, $E_y=A\sin\psi$ and add $B\cos\psi$ along $x$. The resulting semiaxes are $|A+B|$ and $|A|$. Choosing positive $A,B$ gives a nondegenerate ellipse with unequal axes. Uncorrelated relative phases do not describe the same fixed pure polarization.