In this paper, we propose an optical model of the surface color controlled by Ag nanograin structure. A forming method
of Ag nanograin structure on the surface of a silver mirror by chemical conversion treatment was discovered. The surface
has not only unique colors but also properties of bulk metal. The result of SEM observation of the Ag surface showed
nanograin structure and varying in the grain size depending on the color. The size of the grains was from 20nm to 100nm.
We focused on microscopic behavior of electrons in the Ag grain and the permittivity model was formulated based on
Drude Lorentz theory. The model was designed on the assumption that the individual grain behaved like a metallic atom
with bound electron different from the silver. The analytical values of this proposed model were compared with
measurement values in a reflectance spectrum and a chromatic variation.
The mechanical characteristics of polymer materials are of interest to the chemical industry. There are requirements for
observation of changes of internal structure to stress. A number of samples under various stress conditions have
provided interesting information upon analysis by microscopic birefringence measurement. In the present paper, we
propose a birefringence measurement method for observation of the internal structure of polymer materials and analysis
of the relationship between a given stress and the corresponding birefringence distribution. The proposed measurement
system consists of a He-Ne laser, polarizers, a half-wave plate and a quarter-wave plate. The birefringence distributions
of gelatin, such as the phase difference and azimuthal angle, are shown for the case of applied uniaxial and biaxial
The orientation control of liquid crystal (LC) molecular on the polyimide film has been necessary to fabricate LC devices. Nano-rubbing by atomic force microscope (AFM) has been proposed as the one of methods to control it precisely. In the method, a thin polyimide film was rubbed by a sharpened AFM probe-tip with relatively strong load force. However, the method has some drawbacks; the frictional wear of AFM probe-tip and the difficulty of reorientation after rubbing. In this paper, we have proposed the orientation control of LC on the polyimide film and using direct AFM nano-rubbing method with weak load forces. The change of LC alignment was quantitatively observed by a polarization microscope and birefringence-contrast scanning near-field optical microscope. The effect of scanning density was strong for azimuth angle but the effect of the scanning velocity was weak for both retardation and azimuth angle. An optical switching device was developed utilized isotropic-nematic phase change of liquid crystal which was rubbed in the grating pattern with methyl red dying, and the optical device was operated at the frequency of 0.5Hz. As a result, The proposed method had an effective method to fabricate novel liquid crystal optical devices.
A polarization measurement is proposed to detect a birefringence and an optical rotation distribution in a microscopic area. A residual stress caused by industrial processes and molecular orientation are observed by visualizing birefringence distribution. It is possible to analyze components of material with optical rotation. This measurement system consists of a He-Ne laser, polarizers, a half-wave and a quarter-wave plate. By changing combination of rotating angle of half-wave plate, quarter-wave plate and analyzer, we can obtain retardation, azimuthal angle of birefringence and optical rotation angle independently. An analytical algorithm with local-sampling phase shifting is employed for achieving a high resolution. The errors caused by the initial polarized characteristic of the optical system are corrected by subtracting the in-phase vector.
A microscopic birefringence imaging of bio-sample is proposed. This system consists of a super luminescent diode (SLD), polarizers, a quarter-wave plate and a phase retarder. The instrument is provided to map and visualize an optical anisotropy in bio-sample. A local-sampling phase shifting technique is employed for analytic algorithm with high resolution of retardance. A Bereck compensator is used a sample for checking its accuracy. Birefringence distributions of gelatin orientation such as retardance and azimuthal direction are shown in case of applied voltage and changing temperature as its demonstration. It is possible to observe molecular orientation of bio-sample.