Total Reflection Ellipsometry Research Articles

Study on Image Sticking Problem by Means of Total Reflection Ellipsometry

Dynamic response of molecular reorientation near the alignment surface of bistable cholesteric liquid crystal devices was observed by means of the total reflection ellipsometry. From the experimental results, the deviation from the original switching voltage to which the image sticking problem has a close relationship was confirmed, and the cause of the image sticking problem was considered from the viewpoint of the surface energy and Helfrich-type modulation. Especially when the surface free energy is low, director near the alignment surface seems to be distorted by disclinations and Helfrich-type modulation.

Complex refractive index measurement of biological tissues by attenuated total reflection ellipsometry

To apply reflection ellipsometry to determine the real and imaginary parts of the refractive index of biological tissues simultaneously, we combine reflection ellipsometry with total internal reflection to warrant minimal influences by the strong scattering and absorption of biological tissues. A K9 glass prism with refractive index 1.51468 at wavelength 632.8 nm and a Glan prism polarizer with an angular sampling interval of 0.1 degrees were used in our experimental setup. Using the setup, the complex refractive indices of some typical mammalian tissues were measured under the wavelength of 632.8 nm. The results show that the indices of porcine muscle, liver, pancreas, and dermis tissues were 1.3713+0.062i, 1.3791+0.0087i, 1.3517+0.0113i, and 1.3818+0.0049i, respectively.

Optical flickering effect and director fluctuation in nematic liquid crystals studied by total-reflection ellipsometry

Optical flickering effect and director fluctuation in nematic liquid crystals studied by total-reflection ellipsometry

Analysis of Electrical Response of Nematic Liquid Crystal by Ellipsometry

The electrical responses of the LC directors at the bulk and near the surface were investigated by the transmission and the total reflection ellipsometries, respectively. The dynamic response of the δ on the electric field was measured by the transmission ellipsometry. The optical bounce of δ was observed as soon as the high voltage was removed from the LC cell. This bounce is caused by the flow effect in the LC. Since the static response of δ on the electric field measured by the total reflection ellipsometry depended on the interfacial LC director reorientation, the polar anchoring strength of the LC cell was evaluated quantitatively.

Observation of Nematic Liquid Crystal Director Reorientation at the Interface between Substrate and Liquid Crystal Layer by Total Reflection Ellipsometry

The liquid crystal (LC) director reorientation near the interface between the substrate and the LC layer was studied using total reflection ellipsometry (TRE). The dynamic and static responses of the ellipsometric angles to the electric field were measured by TRE. It was experimentally confirmed that total reflection occurs in the LC cell. The reflected light is dominantly modified by the interfacial LC director reorientation. The polar anchoring strength of the cell was estimated by analyzing the electrical response of the phase difference response. We confirm that the TRE is useful for studying the LC director reorientation near the interface between the substrate and the LC layer.

Investigation of Interfacial Liquid Crystal Orientation by Reflection Ellipsometry

The optical techniques, the Brewster angle reflection method, the dye doped reflection ellipsometry and the total reflection ellipsometry, are proposed to investigate the interfacial Liquid Crystal (LC) director orientation. These methods are based on the analysis of the optical polarization of the reflected light from LC cells. From the experimental and theoretical results, it was found that these methods are useful to study the interfacial LC director orientation. Comparison of these methods with one another clarifies the features and the advantages of each one.

3A02 全反射エリプソメトリーによる界面液晶配向の電場応答の解析 (I)

3A02 全反射エリプソメトリーによる界面液晶配向の電場応答の解析 (I)

Measurement of the complex refractive index of liquids in the infrared using spectroscopic attenuated total reflection ellipsometry: correction for depolarization by scattering

With spectroscopic ellipsometry one can measure the real and imaginary parts of the refractive index of a medium simultaneously. To determine this index in the infrared for a number of technical liquids, use was made of attenuated total internal reflection at the glass-liquid interface of a specially designed prism. This attenuated total reflection approach warrants minimal signal loss and is, for strongly absorbing liquids, the only way to measure the complex refractive index. A surprising phenomenon, observed when BK-7 prism glass was used, is scattering in the vicinity of the absorption wavelengths of the glass. A simple model that can be used to describe the relations among absorption, scattering, and depolarization was successfully used to correct the measurements. Refractive indices for demineralized water, Freon 113, heptane, benzene, gas oil, and crude oil in the wave number range from 5000 to 10,000 cm(-1) (1-2 µm) are presented.