Abstract: A spectroscopic measurement device includes: a light source unit configured to output pump light and probe light; a terahertz wave generation unit configured to generate a terahertz wave by the input of the pump light; a terahertz wave detection unit to which the terahertz wave and the probe light are input and configured to modulate the probe light based on a refractive index that changes due to an electro-optical effect according to the input of the terahertz wave; and a light detection unit configured to detect the probe light modulated by the terahertz wave detection unit. A main body unit is configured to include the light source unit and the light detection unit. A measurement unit is configured to include the terahertz wave generation unit and the terahertz wave detection unit. The main body unit and the measurement unit are optically connected to each other by a polarization maintaining fiber.

Abstract: A measurement auxiliary member is placed on an arrangement surface of a prism. A measurement object is placed on an upper surface of the measurement auxiliary member. The measurement auxiliary member totally reflects the terahertz wave input from a lower surface by the upper surface and outputs the totally-reflected terahertz wave from the lower surface. A main pulse of a terahertz wave totally reflected by the upper surface of the measurement auxiliary member without multiply-reflected inside any optical element on an optical path of the terahertz wave, and a noise pulse of a terahertz wave multiply-reflected inside any optical element on the optical path and reflected on an interface between the prism and the measurement auxiliary member, are temporally separated from each other when detecting a correlation by a terahertz wave detection element.

Abstract: A measurement auxiliary member is placed on an arrangement surface of a prism. A measurement object is placed on an upper surface of the measurement auxiliary member. The measurement auxiliary member totally reflects the terahertz wave input from a lower surface by the upper surface and outputs the totally-reflected terahertz wave from the lower surface. A main pulse of a terahertz wave totally reflected by the upper surface of the measurement auxiliary member without multiply-reflected inside any optical element on an optical path of the terahertz wave, and a noise pulse of a terahertz wave multiply-reflected inside any optical element on the optical path and reflected on an interface between the prism and the measurement auxiliary member, are temporally separated from each other when detecting a correlation by a terahertz wave detection element.