Fluorescence confocal polarizing microscopy – a new method for 3D imaging of a director field in liquid crystals – Sergij Shiyanovskii

Date: Mon. September 9th, 2002, 12:30 pm-1:30 pm
Location: Rockefeller 221

Most of traditional optical methods, e.g. polarizing optical microscopy, provide 2D images as a result of the integration over a vertical direction. We have developed a new fluorescence confocal polarizing microscopy (FCPM) technique, which allows one to visualize 3D patterns of the director field in liquid crystals (LCs). FCPM provides clear and easy recognizable images with sub-micron resolution for different textures and defects in LCs, such as confocal domains in smectic A, disclinations and oily streaks in cholesterics, etc. Computer simulations serve as a powerful complementary tool to the FCPM method to decipher unknown complex director configurations. Our numerical code finds equilibrium structures taking into account finite surface anchoring strength, non-local electric field effects, non-equal bulk elastic constants and saddle-splay elasticity, and offers unambiguous recognition of FCPM images. I will discuss the advantages and problems of FCPM and will emphasize efficiency of this method to study biological LCs.