Linear light polarized horizontally passes through a quarterwave plate whose fast axis is $\pi / 8$ rad above the horizontal. Use the phasor method to graphically determine the polarization state of the emerging light. [Hint: $\overrightarrow{\mathbf{E}}$ is along the $x$ -axis below the $x^{\prime}$ -axis, and so the phasor $\mathbf{E}_{y}$ starts pointing downward.