| 摘要 |
PROBLEM TO BE SOLVED: To provide a terahertz radiation (electromagnetic wave) source magnetic circuit which is capable of adopting a laser irradiation configuration where a fiber laser which is not required to be aligned is used, is capable of applying an extremely high magnetic field so as to obtain an output of milliwatts, and adopts a magnetic circuit which never causes a leakage flux and can be lessened in size and weight. SOLUTION: Nearly triangular permanent magnets 1 different from each other in the direction of magnetization are combined so as to form a closed circuit, for instance, magnets which are each nearly triangular in cross section and different from each other in the direction of magnetization, and magnetic materials which are each rectangular in cross section, are combined to form a closed circuit of eight- sided berrel-like body. A yoke-less magnetic circuit is provided each edge face of the eight-sided barrel-like body, by which a strong magnetic field of 3T or above can be produced in a center gap, and a laser beam introducing fine hole is provided to the eight-sided barrel-like body from outside so as to be oriented to the center gap. A laser beam of a fiber laser can be introduced into the center gap without deteriorating a magnetic field in intensity, a magnetic flux hardly leaks out so that a semiconductor device is not adversely affected, and the magnetic circuit device can be easily lessened in size.
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