A Method for Simultaneously Measuring Phase Retardation and Fast Axis of Any Wave Plate

A method for simultaneously measuring phase retardation and fast axis of any wave plate is presented. In this method, a test wave plate is placed between a polarizer and an analyzer, and with no requirements for the initial position of the wave plate. The test wave plate can rotate under the control of a stepping motor. With the rotation of the wave plate, a photoelectric detector is used to detect the output light intensity, and the time-dependent curve of the output intensity can be obtained. Based on the analysis of the curve, the phase retardation and fast axis of the wave plate can be determined at the same time. The advantage of this method is its simplicity, low cost, better accuracy and it can effectively eliminate artificial operation error because of the measuring process is controlled by a computer.