Liquid crystal (LC) adaptive optical elements are described, which provide an alternative to existing micropositioning
technologies in optical tweezing. A full description of this work is given in . An adaptive LC prism supplies tip/tilt
to the phase profile of the trapping beam, giving rise to an available steering radius within the x-y plane of 10 μm.
Additionally, a modally addressed adaptive LC lens provides defocus, offering a z-focal range for the trapping site of
100 μm. The result is full three-dimensional positional control of trapped particle(s) using a simple and wholly
electronic control system. Compared to competing technologies, these devices provide a lower degree of controllability,
but have the advantage of simplicity, cost and light efficiency. Furthermore, due to their birefringence, LC elements
offer the opportunity of the creation of dual optical traps with controllable depth and separation.