This paper presents the results of calculations and optically determined experimental values of the initial director tilt, the layer thickness, and the phase lag for cells with a nematic liquid-crystal (LC). Layers of germanium monoxide (GeO), amorphous hydrogenated carbon (a-C:H), and a combination of them were used in the LC cells to vary the director tilt. Known methods for determining the director tilt are compared with a method proposed by the authors. The proposed method has an advantage in the case of oblique orientation of the slope angle of the LC for angles greater than 15° and is of interest for studying LC devices of adaptive optics, since, along with the main parameter—the maximum phase increment—it makes it possible to estimate the director tilt.
E. A. Konshina, M. A. Fedorov, and L. P. Amosova, "Determining the director tilt and phase lag of liquid-crystal cells by optical methods," J. Opt. Technol. 73, 830-833 (2006)