| 摘要 |
PROBLEM TO BE SOLVED: To simply obtain an image by using a mask made of a light transmittance member except a single light shut-off portion. SOLUTION: For example, a laser beam having a wavelength of 800 nm irradiated from a Ti, sapphire laser 1 is emitted to an indium arsenide board B through a chopper 8. Since a magnetic field of about 1.7 T is applied to the board B by a permanent magnet 2, a strong THz electromagnetic wave (far infrared ray) is emitted. A strength of the THz wave is about 100μW. The THz magnetic wave is converted into a parallel beam by an off-axis parabolic mirror 4, and emitted to an object 12 to be measured. Its transmitted beam is condensed to a bolometer 6 of a detected by an off-axis parabolic mirror 5, and its beam quantity is measured. Detected beam amount data is stored in a computer 11 through a lock-in amplifier 7 used to raise its detecting sensitivity.
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