Implementation of liquid crystal-based polarimeters: trade-off between speed and performance
Résumé
This work considers the implementation of polarimeters with liquid crystal (LC) cells as polarizing elements. Most works generally try to implement architectures with one or two pure retarding modulators such as nematic devices. In this case, rather thick LC devices able to provide a 2π retardation are generally used. Unfortunately, LC device switching speed is known to evolve as the inverse square of their thickness, which leads to practical implementations limited to a few tens of Hertz in the visible region. The alternative consisting in using much faster devices made of ferroelectric liquid crystals is not that obvious since these devices often operate in bistable mode. We show that using thinner, therefore faster nematic devices is possible with a minimal penalty in terms of performance. Therefore, several solutions can be considered. Performance evaluation will be performed through studying the system matrix condition number.