Liquid crystal tunable filters and polarization controllers for biomedical optical imaging

Liquid crystal (LC) devices exhibit fast and strong tuning and switching capabilities using small voltages and can be miniaturized thus have a great potential to be used with miniature optical imaging systems for biomedical applications. LC devices designed specifically for integration into biomedical optical imaging systems are presented. Using a combination of one or two LC retarders we obtained polarimetric imaging of the skin. LC tunable filters with high dynamic range and large throughput are designed for hyperspectral imaging and for spectral domain optical coherence tomography. The designs are based on several concepts both using the classical stack of retarders and using more modern designs based on single layer in a waveguide or in a Fabry-Perot cavity.