>>11575339maxwell's equations are linear, so adding two solutions together gives you another solution. take vertical polarization and add it to horizontal polatization 90 and 270 degrees out of phase with it. you'll get anticlockwise and clockwise polarized waves as a result. these are just as good of basis as the linear horizontal and vertical polarized light to describe any plane wave. in particular, you can recover linear polarization from circularly polarized light by adding/subtracting the ccw and cw waves.