Surface-relief gratings with high spatial frequencies were first fabricated using a direct imprinting process with a glassy carbon mold at the softening temperature of phosphate glass. A grating with maximum height of 730 nm and 500 nm period was formed on the glass surface by the pressing at the softening temperature of glass under constant pressure of 0.4 kN/cm(2). Phase retardation of 0.1 lambda was observed between TE-polarized and TM-polarized light at 600 nm wavelength.

Sawtooth activity on HT-7 tokamak has been investigated experimentally mainly by using soft x-ray diode array and magnetic probes. Their behaviors and occurrences are correlated closely to the discharge conditions: the electron density N e , the electron temperature T,, the safety factor qa on plasma boundary and wall condition etc. When central line-averaged electron density N e ( 0 ) is over 2 . 0~1 0 '~c m -~, major sawtooth activity emerges with a period of up to 6.5 ms and a fluctuation amplitude of up to 2-30 % of SXR radiation signal. In some cases such as the safety factor between 4.2-4.7 and 2,15=3.0-6.0, a monster sawtooth activity often emerges without apparent deterioration of plasma confinement and without major disruption. During these events, abundant MHD phenomena are observed including partial sawtooth oscillations. In this paper, the observed sawtooth behaviors and their dependence on the and their dependence density Ne and wall condition in ohmically heated plasma are introduced, the results are discussed and presented.-PACS: 52.70.La, 52.55.Fa

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A hybrid multibeam module using optical waveguides has been developed for laser scanning optics. The module is constructed using hybrid electrical/optical integration technology. Waveguides and laser diodes are assembled on a silicon substrate on which emitted beams from the laser diodes are coupled into waveguides. For the shorter 780 nm wavelength, which is used for this module, the precision of position control for laser diodes and waveguides must improve below 1 tim. The polyimide waveguides, which are suitable for mass production, are used. It is confirmed that the multibeam module consisting of a beam divergence angle from 10 degrees to 20 degrees, spatial beam interval with a i2-m minimum, and a large number of the beams is possible.