| 摘要 |
PROBLEM TO BE SOLVED: To obtain a terahertz-band optical bandpass filter that maintains a high transmittance even when objective frequencies are increased and that has a predetermined attenuation gain, a transmissive band width and an inhibition band, and in particular, a terahertz-band optical filter that is excellent in temperature characteristics and that allows setting a certain transmissive band width in a wide temperature range. SOLUTION: Cavity layers 1 having an optical path length of n-times ofλ/2 (n is an integer of≥1 ) and made of a low-refractive index medium are arranged in N layers (N is an integer of≥2 ). The cavity layers 1 are coupled through a single layer of coupling layer 4 having an optical path length ofλ/4 and made of a high-refractive index medium, thus forming a multi-cavity structure 30. At both ends of the multi-cavity structure 30, matching layers 40 composed of a high-refractive index layer 2 and a low-refractive index layer 3 each having an optical path length ofλ/4 are arranged. COPYRIGHT: (C)2008,JPO&INPIT
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