Abstract

Liquid crystal (LC) devices are described, which modulate the orientation of incoming linearly polarized light. The reorientation is due to the twisted nematic effect and is therefore achromatic. In contrast to practically all other LC devices, the elements described here use alignment layers with modulated orientations [1]. Two new classes of LC devices will be considered. First, LC devices with macroscopic modulations leading to polarization converter devices will be examined. They are capable of generating linearly polarized light with axial symmetry, the beam propagation axis representing the symmetry axis [2]. When such polarization converters are illuminated with circularly polarized light they behave as achromatic spiral phaseplates [3] of integer order.

© 1996 IEEE