Abstract: This invention addresses the abovementioned problem, and the purpose of this invention is to provide a far-infrared spectroscopy device that uses an is-TPG method to generate far-infrared light, and is capable of efficiently detecting is-TPG light without a detection optical system being fine-tuned. Even if the far-infrared light incidence angles on an Si prism for detection are the same when far-infrared light having a first frequency is incident on a non-linear optical crystal for detection and when far-infrared light having a second frequency is incident on the non-linear optical crystal for detection, this far-infrared spectroscopy device adjusts the incidence surface angle of pump light in relation to the non-linear optical crystal for detection such that the angle of the far-infrared light in relation to the pump light within the non-linear optical crystal for detection can be appropriately set for each far-infrared light frequency (see FIG. 1A).

Abstract: This far-infrared spectroscopy device comprises a holding mechanism that is capable of holding a sample in humid air, a detector for detecting light obtained by emitting far infrared light onto the sample, and a signal processing unit for calculating an absorption spectrum of the sample from a signal from the detector. The signal processing unit comprises a threshold processing unit that subjects the signal from the detector to threshold processing and removes the part of the signal influenced by the absorption by the water vapor in the humid air, a signal interpolation unit that carries out interpolation on the signal that has been subjected to the removal by the threshold processing unit, and an absorbance calculation unit for calculating an absorbance from the signal that has been subjected to the interpolation by the signal interpolation unit.

Abstract: The present invention provides a far-infrared light source capable of reducing the shift in the location irradiated with far-infrared light even when the frequency of the far-infrared light changes. A far-infrared light source according to the present invention is configured so that the variation in the emission angle of far-infrared light in a nonlinear optical crystal when the frequency of the far-infrared light changes is substantially offset by the variation in the refractive angle of the far-infrared light at the interface between the nonlinear optical crystal and a prism when the frequency of the far-infrared light changes (see FIG. 8).

Abstract: This invention addresses the abovementioned problem, and the purpose of this invention is to provide a far-infrared spectroscopy device that uses an is-TPG method to generate far-infrared light, and is capable of efficiently detecting is-TPG light without a detection optical system being fine-tuned. Even if the far-infrared light incidence angles on an Si prism for detection are the same when far-infrared light having a first frequency is incident on a non-linear optical crystal for detection and when far-infrared light having a second frequency is incident on the non-linear optical crystal for detection, this far-infrared. spectroscopy device adjusts the incidence surface angle of pump light in relation to the non-linear optical crystal for detection such that the angle of the far-infrared light in relation to the pump light within the non-linear optical crystal for detection can be appropriately set for each far-infrared light frequency (see FIG. 1A).

Abstract: The present invention provides a far-infrared light source capable of reducing the shift in the location irradiated with far-infrared light even when the frequency of the far-infrared light changes. A far-infrared light source according to the present invention is configured so that the variation in the emission angle of far-infrared light in a nonlinear optical crystal when the frequency of the far-infrared light changes is substantially offset by the variation in the refractive angle of the far-infrared light at the interface between the nonlinear optical crystal and a prism when the frequency of the far-infrared light changes (see FIG. 8).

Abstract: In an is-TPG method in which lasers having two different wavelengths are used to generate a wavelength-variable far-infrared light, a far-infrared light (TPG light) having an unstable output at a broad wavelength is also slightly generated at the same time with only one laser light. The generated is-TPG and the TPG light are converted, after passing through a specimen, to near-infrared light inside a nonlinear optical crystal for detection and are observed by a detector. The signal light output of the is-TPG light becomes unstable due to the TPG light. According to the present invention, the TPG light is removed by means of a slit and the like (filter) immediately before the specimen and is not introduced into the nonlinear optical crystal for detection. At this time, by using a change in the emission direction when the frequency of the is TPG light is changed, the filter is moved in accordance with the frequency so that only the is-TPG light passes therethrough (see FIG. 1C).

Abstract: In an is-TPG method in which lasers having two different wavelengths are used to generate a wavelength-variable far-infrared light, a far-infrared light (TPG light) having an unstable output at a broad wavelength is also slightly generated at the same time with only one laser light. The generated is-TPG and the TPG light are converted, after passing through a specimen, to near-infrared light inside a nonlinear optical crystal for detection and are observed by a detector. The signal light output of the is-TPG light becomes unstable due to the TPG light. According to the present invention, the TPG light is removed by means of a slit and the like (filter) immediately before the specimen and is not introduced into the nonlinear optical crystal for detection. At this time, by using a change in the emission direction when the frequency of the is TPG light is changed, the filter is moved in accordance with the frequency so that only the is-TPG light passes therethrough.

Abstract: The present invention provides a far-infrared light source capable of reducing the shift in the location irradiated with far-infrared light even when the frequency of the far-infrared light changes.