This paper presents a hard-magnetic-material-type rotary device whose axis of rotation is parallel to the direction of the exciting magnetic field. Permanent magnets and some silicon steel sheets were used to obtain the radial components of the field strength. Because the principle of movement is similar to that of synchronous motors, the starting torque was still small and the moving direction was also unstable. To solve these problems, the permanent magnets distributed on the rotor surface were inclined to the fixed rotation direction. In addition, triangular silicon steel sheets were used instead of the previous rectangular ones. And still more, we gave the other two permanent magnets to the axis of rotation. Measurement results show that the improved device has a starting torque in the fixed direction of motion and it's starting torque is larger than the previous one.

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We show an application of a scanning near-field optical microscopy (SNOM) to nanofabrication. SNOM can obtain a resolution beyond the diffraction limit by placing a subwavelength aperture in close proximity to a sample. A sharpened and bent optical fiber with a small aperture is used as a near-field optical probe as well as a cantilever of an atomic force microscope (AFM). To improve the optical resolution, the aperture should be placed as close to the sample as possible. In order to decrease the distance between the aperture and the sample, a thin optical fiber probe with low spring constant (-10N/m) is operated in contact mode. Positive photoresist film for g-line (λ=436nm) is exposed by the near-field light from the thin optical fiber probe coupled by a He-Cd laser (λ=442nm) and developed normally. Groove pattern as narrow as 80nm in full width is produced in the photoresist film on a Si wafer. The exposure characteristics of the photoresist illuminated by the near-field light are discussed.

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A miniaturized fiber-optic pressure sensor 125μm in diameter has been developed for the measurement in human body [1]. The sensing element is fabricated by micromachining, and attached to the end of an optical fiber using polyimide adhesive layer. A Fabry-Perot interferometer is constituted of a half-mirror at the fiber end and a reflection mirror on the movable thin diaphragm. The intensity of the light reflected at the interferometer is modulated by the pressure, because the optical path difference between the two mirrors of the interferometer varies with the displacement of the diaphragm in dependence on the pressure.

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