Distortion of a liquid crystal bulk by the Casimir torque

We present an experimental method for measuring the Casimir torque acting on liquid crystals from a birefringent crystal. A liquid crystal bulk that is uniformly aligned at one surface is twisted at the other surface by a crystal such as barium titanate. The liquid crystal is separated from the solid crystal by an isotropic, transparent material such as SiO$_{2}$. By varying the thickness of the deposited layer, we can observe the effect of retardation on the torque (which differentiates it from the close-range van der Waals torque) and compare experimental results to dispersion data of the materials. We find that a barium titanate slab could cause 5CB liquid crystal to rotate by 10 degrees through its bulk, even when separated by 35 nm of SiO$_{2}$. The optical technique for measuring this distortion is also outlined.