 Evidently, the effect of the half-wave plate is to mirror the wave's polarization vector through the plane formed by the vectors formula_4 and formula_13.For linearly polarized light, this is equivalent to saying that the effect of the half-wave plate is to rotate the polarization vector through an angle 2θ; however, for elliptically polarized light the half-wave plate also has the effect of inverting the light's handedness.For a quarter-wave plate, the relationship between "L", Δ"n", and λ0 is chosen so that the phase shift between polarization components is Γ = π/2.