ABSTRACT
We present an experimental approach for the fast measurement of twisted nematic (TN) liquid crystal (LC) cells' parameters. It is based on the spectral measurements of the light transmitted by the system polarizer-reference wave plate-LC cell-analyzer. The cell parameters are obtained by fitting the theoretical model to the experimental data. This method allows determining the rubbing angle, the twist angle and its sense, and the spectral dispersion of the LC cell retardation, simultaneously, with few measurements and without the need of applying voltage or any specific analytical conditions. The method is validated by characterizing two different TN cells with retardations of about 0.91 and 1.85 µm. The birefringence relative error is less than 1.3%.
ABSTRACT
A reconfigurable 1×2 wavelength selective switch, based on a Lyot filter and high birefringence nematic liquid crystals, is proposed. Simulations and experimental results of a reconfigurable switch are reported. Insertion losses from 3.4 dB and rejection ratios up to 15 dB are obtained in a two input channel system at 560 and 621 nm. Control voltages of 0 to 3 V(RMS) are used.
