Measurement of refractive indices of the liquid crystal mixtures Merck 10400-000 and 10400-100 at the infrared wavelength lambda=1550 nm

In this work the extraordinary and ordinary refractive indices of different commercial liquid crystal (LC) compounds have been measured at the wavelength lambda = 1550nm. Four samples have been investigated. Two of them are LCs Merck 10400-000 and 10400-100. The other two have been obtained mixing the previous LCs in different proportions. The method used for the measurement is based on a refractometric technique that takes advantage of refraction of a narrow laser beam by a wedged shaped LC cell. The method allows the measurement of both the extraordinary and ordinary refractive indices of the LC. The measurement of the angle of the wedged cell is a very critical point and it has been performed by means of an optical method. The refractive indices have been measured at different temperatures.