LINEARLY POLARIZED-LIGHT WITH AXIAL SYMMETRY GENERATED BY LIQUID-CRYSTAL POLARIZATION CONVERTERS

Novel liquid-crystal devices are described that generate linearly pola rized light with axial symmetry; the beam propagation axis is the symm etry axis. Such light fields can be characterized by a polarization or der number P. For example, P = 1 fields represent radially or azimutha lly polarized light. The reorientation of the polarization orientation in these polarization converters is due to the twisted nematic effect and the effect of lambda/2 wave plates. A single polarization convert er can generate fields of orders 1 and 2. It is shown that one can in principle generate fields of any integral order P by cascading such el ements. Devices that generate P = 1 fields are achromatic and can be u sed as polarization axis finders or as versatile tools for studying bi refringent or polarizing materials. (C) 1996 Optical Society of Americ a.