To provide a frequency converter operable within a wide frequency range from a microwave to a terahertz wave which does not use a solid state device having non-linear characteristic and does not need a complicated resonator structure. 非線形特性を持つ固体素子を使用せず、複雑な共振器構造も必要としない、マイクロ波からテラヘルツ波に至る幅広い周波数範囲で動作可能な周波数変換装置を提供すること。 - 特許庁