Measurement and numerical simulations for twisted nematic liquid crystal

The dataset contains the results of measuring the polarization state of light passing through a TNLC (twisted nematic liquid crystal) manufactured by Thorlabs® and calculated from this the voltage-polrization characteristics (azimuth and ellipticity angle and phase difference) of the measured samples (STN71, STN72). For measurement was used a simple polarimetric system. Thorlabs® compact laser module with a wavelength of 638.5 nm combined with a Thorlabs® fixed magnification beam expander is used as the light source. Using a Melles-Griot® linear polarizer, linearly polarized input lights with azimuth angles of 0°, 45° and 90° are generated. Then the light is passed through the examined TNLC medium. The voltage applied to the TNLC is controlled by a digital-to-analog converter DAC. The ready-made Thorlabs® polarimeter system PAX is used to measure the intensity of the input and output lights and determine the azimuth and ellipticity angles of the light outgoing from the medium. For calculations was used the algorithm presented in [1].In addition, there are available the results of calculations of minimum condition number of the matrix describing the behavior of the simple elliptical analyzer system, consisting of a linear polarizer and TNLC with parameters derived from measured characteristics – maximum modulation of the phase difference up to 1.2π. For each possible azimuthal setting of the polarizer in the range 0÷π, four phases from the modulation range 0÷1.2π were randomly generated and the minimum CN value was found for among 100,000 such trials.[1] Woźniak W.A. and Kurzynowski P., "The method of measurement of optical properties of birefringent media," Optik 96(4), 147 - 151 (1994).