When an isotropically polarized light beam is passed through a linear polarizer followed by a quarter-wave compensator, the polarization of the emergent light can be made to assume all possible states (represented by the points in the complex plane) by rotating the polarizer and compensator around the beam axis. With regard to this arrangement the complex polarization variable is a function of and , , where and represent the azimuths of the transmission axis of the polarizer and the fast axis of the compensator, respectively, measured from the axis (counterclockwise, looking into the beam) of the space-fixed Cartesian coordinate system whose axis is along the direction of propagation of the incident light beam.