Applications for interferometry and sub-millisecond phase modulation with liquid crystal light valves

Liquid crystal (LC) devices have large applications, for example in displays and light projection. The typical bandwidth is ~100 Hz, corresponding to large refractive index changes of the order of ~ 0.1. In LC with planar anchoring the index of refraction depends on the applied voltage V . A full birefringence excursion occurs from a few Volts (Fréedericksz transition voltage V th ) to ~10 V when all the molecules tend to align perpendicular to the cell wall. The switching time is related to the applied voltage through the equation [1] \begin{equation*}T = \frac{{{\gamma _1}{d^2}}}{{K{\pi ^2}\left[ {{{\left( {\frac{V}{{{V_{th}}}}} \right)}^2} - 1} \right]}},\end{equation*} where γ 1 is the LC rotational viscosity, K the elastic constant and d the thickness of the LC layer. These parameters can be used to decrease T by changing the temperature, the applied voltage or the LC thickness.