Polarization-independent and submillisecond response phase modulators using a 90 degrees twisted dual-frequency liquid crystal

A polarization-independent phase modulator using a 90 degrees twisted dual-frequency liquid crystal (DFLC) is demonstrated. In addition to being polarization independent, such a phase modulator exhibits many other advantages such as being scattering-free and having large phase change, low operating voltage, and submillisecond response time. Using a 15 mu m transmissive DFLC cell, the phase shift achieves 1 pi at lambda = 633 nm and the applied voltage is lower than 25 V-rms. Potential applications of such a phase modulator for laser beam steering, tunable-focus lenses, and switchable two-dimensional/three-dimensional liquid crystal displays are foreseeable