In this work, we present a complete process to obtain a pure phase modulator based on a twisted nematic liquid crystal display (TNLCD). We first describe a simple technique for measuring the physical parameters of each cell of this device with no ambiguities, and we use them to build a simplified model of the display based on the Jones matrix theory. Then, after selecting a proper optical system for pure phase modulation, an optimal configuration of the system is searched using a numerical algorithm. This procedure drastically reduces the voluminous experimental stage this task normally requires.
The presented method is verified through experimental results, finding an excellent agreement between the measurements and the predicted data.
