Mueller matrix polarimetric analysis applied to characterize the physical parameters of a twisted-nematic liquid–crystal modulator

•This work presents study of a twisted-nematic (TN) liquid–crystal (LC) modulator in order to achieve a precise prediction of its optical modulation properties.•The novelty of the approach here presented is that combines a physical model of the LC distribution, extended to the Mueller matrix polarimetric approach. This allows characterizing physical parameters, like the twist angle, the orientation of the LC director axis and the maximum retardance.•The technique simplifies previous approaches with the advantage of employing a single wavelength. Noteworthy, it also resolves the ambiguities in the determination of the physical parameters.•A simplified procedure is presented under the assumption that the TN-LC cell is a pure retarder component, which is useful to perform a rapid calibration of the device for its rapid configuration in the laboratory. This work presents a complete polarimetric study of a twisted-nematic (TN) liquid–crystal (LC) cell. We review the physical models that describe the cell and analyze the different modulation regimes. We extend the usual Jones matrix approach, where these microscopic physical models were developed, to the corresponding Mueller matrix approach. This polarimetric analysis is then used to obtain the effective linear and circular retardance components of the cell and to characterize its physical parameters like the twist angle, the orientation of the LC director axis and the maximum retardance. The technique simplifies previous approaches with the advantage of employing a single wavelength. Noteworthy, it also resolves the ambiguities in the determination of the physical parameters. Experimental evidence of the effectiveness in predicting the optical modulation is shown for a single-pixel TN-LC cell. Finally, a simplified procedure is presented under the assumption that the TN-LC cell is a pure retarder component, which is useful to perform a rapid calibration of the device.