Guided Wave Studies of Reflective MTN Liquid Crystal Cell

The fully-leaky guided wave technique has been used to study the reflective 90 ̊ MTN liquid crystal cell used for LCOS. The cell is comprised of upper substrate with indium-tin-oxide coating and lower substrate with aluminum coating. Reflective angle-dependent signals (Rss, Rpp, Rsp and Rps) were recorded over a range of angles of incidence with the cell under application of 0 7 Vrms ac electric fields. From the recorded experimental data, we found the reflective signals are quite strong, especially the polarization conversion signals. Fitting the data in reflection with the results of the modeling-program gives the information about the pre-tilt and twist of the director as well as the parameters of different optical layers. We found that the pre-tilt angle on the upper substrate is different from that on the bottom in the best fits, which suggests that the indium-tin-oxide and the aluminum coatings have different effects on the alignment layers.