A very simple and accurate way to measure the transmission axis of a linear polarizer

A simple and practical method is introduced to obtain the transmission axis of a linear polarizer. The method utilizes non-normal incidence of light through the polarizer whose transmission axis needs to be measured. In the measurement process, a scan of either the vertical or horizontal tilt of the polarizer is performed to impose intentional misalignment on the optical train, and the apparent polarization angles after the polarizer are measured over the scan by a conventional polarimeter. The experimental data is fit based on the mathematical model established by a chain of matrices that characterizes the propagation and interaction of the polarized light to obtain the transmission axis of the polarizer with high precision and accuracy. An example of the practice demonstrates this methodology can infer the transmission axis of the polarizer with an accuracy of a tenth of a degree.