By means of the full leaky guided mode technique, the transmittance of the full leaky waveguide geometry which consists of pyramid, matching fluid of refractivity, the vertical alignment nematic liquid crystal cell are investigated experimentally. The experimental curves with different voltages between polarization-conserving transmittance Tss and the internal angle (the angle of incidence for which light is incident on the vertical alignment liquid crystal cell) are obtained. Comparing these experimental curves with the theoretical curves obtained from multi-layer optics theory, the director profile of vertical alignment nematic liquid crystal cell for different voltages is determined.

The fully-leaky waveguide technique has been used to explore the director of inverse twisted nematic liquid crystal cell. The reflection data, including all the polarization-conserving signals Rpp and Rss as well as the polarization-conversion signals Rsp and Rps, are recorded under various voltages applied to the cell of 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, and 7.0V (rms), at a frequency of 1kHz. We found that this technique was sensitive to the director changes, especially for the polarization-conversion signals. Then by fitting angle-dependent reflectivity data to modeling theory, the arrangement of the director and some importance parameters of liquid crystal cell are obtained. It is proved that the reflectivity of fully-leaky waveguide mode can give the imperceptibility change in the cell.