How to measure the Mueller matrix of liquid-crystal cells

The Mueller matrix is the transfer matrix in the. Stokes algebra that descr ibes the polarization of natural light. This matrix is very versatile for t he task of characterizing the optical properties of liquid-crystal cells, s ince it can be used for comparison. with theoretical calculations, the dete rmination of material parameters and the modelling of the cell as an optica l building block for technological use. We have constructed a Mueller-matri x spectrometer, with the ability to perform fast, dynamic measurements of t he Mueller matrix of small areas of liquid-crystal cells throughout the vis ible range. To illustrate the potential of the instrument, dynamic measurem ents on a ferroelectric-liquid-crystal cell are presented and analysed. The optical measurements indicate that there is an asymmetry between the up an d the down state, tilted smectic layers and polarization reversal initiated at the boundaries.