A vertically stacked directional coupler incorporating electro-optic poled polymer was fabricated by spin coating, photolithography, and reactive ion etching processes, based on the fabrication technique used for polymeric single-mode channel waveguides. Vertically coupled operation at 1.3 μm have been achieved between two stacked channels which were kept 3.5–5 μm apart by a narrow cladding layer. The intensity modulation has been clearly demonstrated in the coupler with electrodes when a voltage is applied at 10 kHz between them.

It is shown that a-c powder EL deterioration is closely related to sulfur vacancy in the phosphor and the phosphor crystal quality, by measurement of ESR spectrum and x-ray diffraction pattern. The EL phosphor life is improved with a decrease in the sulfur vacancy density in the phosphor. It is further improved with a decrease in the x-ray diffraction (111) peak intensity of the phosphor. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-05-31 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.210.126.199 Downloaded on 2015-05-31 to IP Vol. 130, No. 11

A bistable spatial light modulator is developed by utilizing optical bistability of ferroelectric liquid-crystal molecule.Both positive and negative images are read out by changing the polarity of applied electric pulses. A binary image is stored for more than 2 h, and gray-level operation is also possible during the gradual decay after writing.

The composition dependence of the helical twisting power in various mixtures of cholesteric-cholesteric or nematic-cholesteric liquid crystals is investigated by measuring transmission or reflection spectra. In the binary cholesteric mixtures, the helical twisting power varies monotonously with the composition except in left-handed cholesteric-rich regions. In the namatic-cholesteric mixtures, the helical twisting power varies with the composition through a maximum value and the helical sense of these mixtures with a small amount of cholesterics is left-handed regardless of the helical sense of cholesteric components. Further, in the mixtures of nematics and right-handed cholesterics, cholesteric-to-nematic phase transition is observed.

We give an analytical solution for the nonlinear equation of motion of an electron beam in the radial direction of a superconducting tube, for the case of electrons moving close to the tube axis, in the complete flux expulsion model. Hence, we deduce a general expression for the focusing length that is dependent on the parameters of the superconducting tube and electron stream. Our focusing length is inversely proportional to x 0 , the width of the electron beam, and is in good agreement with experimental data.