JP2010210543A - Sensor unit, terahertz spectral measurement apparatus, and terahertz spectral measurement method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor unit, a terahertz spectral measurement apparatus and a terahertz spectral measurement method for improving the measurement accuracy without an effect by an absorption of a terahertz light due to water vapor. <P>SOLUTION: The sensor unit 10 includes: a light emitting element section 11 having a light emitting element for generating the terahertz light; a light receiving element section 11 having a light receiving element for receiving the terahertz light, and detecting a detection signal; and a reflection element section 12 having a reflection surface 122 for reflecting the terahertz light. The light emitting element section 11, the light receiving element section 11 and the reflection element section 12 are integrally bonded. A flow path section 13 is formed between optical paths of the light emitting element section 11 and the light receiving element section 11 so as to flow a sample S. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sensor unit using terahertz light, a terahertz spectrometer, and a terahertz spectrometer method.

  In recent years, a terahertz time domain spectroscopy (THz-TDS: THz-TimeDomain) in which a sample is irradiated with light in a terahertz frequency range (0.1 THz to 10 THz) and transmitted light transmitted through the sample or reflected light reflected from the sample is detected. (Spectroscopy) is drawing attention. This terahertz time-domain spectroscopy method uses a terahertz pulse spectrometer to measure the electric field strength of a sample that depends on the time of terahertz light and performs Fourier transform processing on the time-series data depending on the time. It is possible to obtain frequency dependency such as electric field strength and phase to be formed (see Patent Document 1).

  A terahertz spectrometer is known in which a terahertz light waveguide connecting a light emitting element and a light receiving element is formed for the purpose of downsizing the apparatus, and a channel through which a sample flows is formed in the center. (See Patent Document 2).

WO00 / 079248 JP 2007-178189 A

  In the terahertz spectrometer described in Patent Document 1, the light emitting element and the light receiving element are separated from each other, and the sample is disposed therebetween. For this reason, the terahertz light is not only absorbed from the sample, but also derived from water vapor contained in the atmosphere in the optical path from the light emitting element to the light receiving element until it enters the light receiving element. Absorption is also received. The absorption by the atmosphere becomes a measurement error, and there is a problem that causes a decrease in measurement accuracy of the terahertz spectrometer. Further, in order to avoid this absorption by water vapor, the conventional spectroscopic measurement apparatus is evacuated or filled with dry nitrogen. Therefore, a vacuum pump, a nitrogen tank, etc. were needed and the apparatus was large.

  In addition, since the light emitting element and the light receiving element are separated from each other, the terahertz light is focused by an off-axis paraboloidal mirror or the like in order to concentrate the divergence of the terahertz light emitted from the light emitting element upon incidence on the light receiving element. There is a problem that the terahertz spectrometer needs to be adjusted and the configuration of the terahertz spectrometer becomes complicated.

  Since the space between the light emitting element and the light receiving element is sealed, the terahertz spectrometer described in Patent Document 2 can avoid absorption due to water vapor in the atmosphere. However, a terahertz light waveguide must be formed in the substrate, which is difficult to manufacture and has a complicated structure.

  An object of the present invention is to provide a sensor unit, a terahertz spectrometer, and a terahertz spectrometer method with high measurement accuracy in which terahertz light is not affected by the absorption spectrum of water vapor.

[Application Example 1]
A sensor unit according to this application example includes a light emitting element portion having a light emitting element that generates terahertz light, a light receiving element portion having a light receiving element that receives the terahertz light and detects a detection signal, and is emitted from the light emitting element portion. A reflective element part having a reflective surface for reflecting the terahertz light to the light receiving element part, and the light emitting element part, the light receiving element part and the reflective element part are integrally joined, and the light emitting element part And a flow path portion for allowing a sample to flow between the optical paths between the light receiving element portion and the light receiving element portion.

In this application example of this configuration, the terahertz light from the light emitting element part is reflected back by the reflecting element part and is incident on the light receiving element part, thereby joining the light emitting element part and the light receiving element part integrally. It can be made.
Furthermore, since the light emitting element part, the light receiving element part, and the reflecting element part are joined, they can be reduced in size as compared with a sensor unit in which these are separated from each other and a sample is disposed therebetween.

In this application example, the light emitting element part and the light receiving element part are integrally joined, and the flow path part of the sample is formed on the optical path between the light emitting element part and the light receiving element part. The substrate, the base material of the reflection element portion, and the sample in the flow path portion are only included.
Therefore, terahertz light is not absorbed by water vapor in the atmosphere, and only absorption derived from the sample can be detected by the light receiving element portion. Therefore, the sensor unit according to this application example can have high measurement accuracy.

  Further, since the light emitting element portion and the light receiving element portion are joined and the flow path portion is formed between them, the optical system is not displaced, and measurement can always be performed in an optimum state.

[Application Example 2]
In the sensor unit according to this application example, it is preferable that the light emitting element unit and the light receiving element unit are light emitting and receiving element units in which the light emitting element and the light receiving element are provided on the same surface.
In this application example of this configuration, since the light emitting element and the light receiving element are formed on the same substrate, the light emitting element and the light receiving element can be simultaneously formed in a batch process, and a simpler configuration is provided. In addition, the sensor unit can be further downsized.

[Application Example 3]
In the sensor unit according to this application example, it is preferable that the flow path portion is formed in at least one of the light emitting element portion, the light receiving element portion, and the reflecting element portion.
In this application example having this configuration, the flow path portion through which the sample is circulated is formed in at least one of the light emitting element portion, the light receiving element portion, and the reflecting element portion. Therefore, the light emitting element portion, the light receiving element portion, and the reflecting element The channel portion can be formed between the light emitting element portion or the light receiving element portion and the reflecting element portion simply by joining them together.
For this reason, the sensor unit according to this application example can have a simple configuration, and the sensor unit can be easily manufactured.

[Application Example 4]
In the sensor unit according to this application example, it is preferable that the flow path section is partitioned by a spacer.
In this application example of this configuration, since the flow path portion is partitioned by the spacer, the light emitting element portion and the light receiving element can be obtained simply by sandwiching the spacer between the light emitting element portion or the light receiving element portion and the optical element. A flow path can be formed along the part and the optical element.
For this reason, the sensor unit according to this application example can have a simple configuration, and the sensor unit can be easily manufactured.

[Application Example 5]
The sensor unit according to this application example includes a light emitting element portion having a light emitting element that generates terahertz light, a light receiving element portion that receives the terahertz light and detects a detection signal, and a reflective portion having a flow path portion. An element portion, and the light emitting element portion, the light receiving element portion, and the reflecting element portion are integrally joined, and the terahertz light is emitted from the light emitting element portion and totally reflected at the flow path portion. And is totally reflected and incident on the light receiving element portion.
In this application example having this configuration, the terahertz light is incident and totally reflected at the angle of total reflection in the flow path portion, so that it is not necessary to provide a reflection surface in the reflection element portion.
For this reason, it can be set as a simpler structure, and also a sensor unit can be reduced in size.

[Application Example 6]
In the sensor unit according to this application example, the light emitting / receiving element portion is provided with an optical fiber that guides laser light to the light emitting element portion on the opposite side of the joint surface between the light emitting / receiving element portion and the reflecting element portion. It is preferable.
In this application example of this configuration, since it has a mounting portion that can be engaged with and disengaged from the covering member that covers the electrode, by engaging other members and parts with this mounting portion, members, parts, etc., for example, An optical fiber can be easily attached. When an optical fiber is attached to this attachment part, the pulse laser light is guided to the light emitting element part or the light receiving element part by the optical fiber, so there is no need to bend the optical path of the pulse laser light by reflection of a mirror or the like. The optical path of the pulse laser beam can be freely bent by bending.

[Application Example 7]
A terahertz spectrometer according to this application example includes the above-described sensor unit, a laser oscillator that irradiates a laser beam that irradiates the light receiving element unit, and an analysis unit that performs an analysis process using the detection signal. It is characterized by that.
In this application example having this configuration, an analysis unit that performs analysis processing from a signal detected by the light receiving element unit is provided, and thus analysis and analysis of the obtained detection signal can be performed simultaneously with terahertz spectroscopy measurement. Therefore, terahertz spectroscopy measurement and its analysis and analysis can be performed at a time, so that a measurement result can be obtained in a short time.
In addition, the terahertz spectrometer having the sensor unit introduced therein can omit a condensing optical system such as an off-axis parabolic mirror, and can be a compact spectrometer with a simple configuration.

[Application Example 8]
A terahertz spectrometry method according to this application example is a terahertz spectrometry method using the above-described terahertz spectrometer, and a standard sample detection step of detecting a detection signal by flowing a standard sample into the flow path section A discharge step of discharging the standard sample from the flow channel portion, a sample detection step of detecting a detection signal by flowing the sample into the flow channel portion, the detection signal obtained in the standard sample detection step, and the And an analysis processing step of analyzing the sample by comparing with the detection signal obtained in the sample detection step.
In this application example having this configuration, the absorption spectrum by the standard sample is detected, and then the absorption spectrum by the sample is detected. Since the measurement and evaluation are performed by dividing the detection signal of the absorption spectrum by the sample by the detection signal of the absorption spectrum by the standard sample, measurement based on the absorption spectrum of the standard sample can be performed. Therefore, stable measurement accuracy can be ensured.

1 is a configuration diagram of a terahertz spectrometer in a first embodiment of the present invention. The expanded sectional view of the sensor unit in a 1st embodiment of the present invention. The perspective view of the concave mirror in 1st Embodiment of this invention. The schematic diagram showing the manufacturing method of the sensor unit in 1st Embodiment of this invention. The schematic diagram showing the distribution | circulation state of the sample in the flow path in 1st Embodiment of this invention. The schematic diagram showing the manufacturing method of the sensor unit in 2nd Embodiment of this invention. The schematic diagram showing the sensor unit in 3rd Embodiment of this invention. The schematic diagram showing the sensor unit in 4th Embodiment of this invention. The schematic diagram showing the optical path of the evanescent wave in 4th Embodiment of this invention. The schematic diagram showing the sensor unit in the modification of this invention. The schematic diagram showing the sensor unit in the modification of this invention.

Embodiments of the present invention will be described with reference to the drawings. Here, in each embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted or simplified.
(First embodiment)
A terahertz spectrometer which is a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a block diagram of a terahertz spectrometer in the first embodiment of the present invention.
As shown in FIG. 1, the terahertz spectrometer 1 of the present embodiment includes a pulsed light source 100 as a laser oscillator that generates laser light 30 at a predetermined period, and the laser light 30 generated from the pulsed light source 100 as excitation light. A beam splitter 21 for separating the probe light, an excitation optical system 31 for guiding the excitation light, a sensor unit 10 irradiated with the excitation light guided by the excitation optical system 31, and a probe light A probe optical system 32, a variable optical delay 40 for adjusting and setting a timing difference of the probe light with respect to the excitation light, and a spectral processing unit 50 as an analysis means for processing a detection signal from the sensor unit 10. I have.

Here, as the pulse light source 100, for example, a pulse laser device such as a femtosecond pulse laser can be used.
The sensor unit 10 includes a light emitting / receiving element portion 11 and a concave mirror 12. The light emitting and receiving element unit 11 generates terahertz light when irradiated with excitation light from the excitation optical system 31 and receives terahertz light transmitted through the sample S in the flow path unit 13.

The excitation optical system 31 is an optical path that guides the laser light 30 to the sensor unit 10 by the beam splitter 21.
The variable optical delay device 40 includes a movable reflecting mirror 41 that can freely move in a direction parallel to the optical axis of the probe light, an optical delay control device 42 that controls the movement of the movable reflecting mirror 41, and the probe optical system 32. And a fixed reflecting mirror 43 that guides the sensor unit 10 to the sensor unit 10.
The optical delay control device 42 is for driving and controlling the position of the movable reflecting mirror 41. By driving and controlling the position of the movable reflecting mirror 41, the setting / change of the optical path length of the probe light is controlled, so that the irradiation timing difference between the excitation light and the probe light (terahertz light generation / detection timing difference) Control changes.

The spectroscopic processing unit 50 includes an A / D converter 51, a spectrum analysis device 52, and an analysis device 53.
The A / D converter 51 is for converting the analog signal of the current supplied from the light emitting / receiving element unit 11 into a digital signal.
The spectrum analyzer 52 records the digital signal converted by the A / D converter 51 and obtains an intensity distribution for each frequency of the terahertz light by performing Fourier transform.

  The analysis device 53 is for obtaining the spectral characteristics of the sample S in the flow path unit 13 based on the intensity spectrum obtained by the spectrum analysis device 52. The analysis device 53 is composed of a personal computer or the like, performs an arithmetic process necessary for obtaining the terahertz light spectral characteristics of the sample S based on the amplitude spectrum data obtained by the spectrum analysis device 52, and performs the terahertz light spectroscopy of the sample S. Get properties.

FIG. 2 is an enlarged cross-sectional view of the sensor unit according to the first embodiment of the present invention.
As shown in FIG. 2, the sensor unit 10 includes a flat light emitting / receiving element portion 11 and a semi-elliptical concave mirror 12 as a reflecting element portion. The sensor unit 10 is formed by joining the light emitting / receiving element portion 11 and the concave mirror 12 together in a plane.
The light emitting / receiving element unit 11 has a flat plate-shaped gallium arsenide substrate (hereinafter referred to as a GaAs substrate) 111. The GaAs substrate 111 is provided with a low-temperature grown gallium arsenide substrate (hereinafter referred to as an LT-GaAs substrate) 112 on the side opposite to the joint surface with the concave mirror 12. The LT-GaAs substrate 112 is obtained by depositing gallium arsenide on the GaAs substrate 111 by a molecular beam epitaxial method, specifically, in a temperature range of about 200 ° C. to 400 ° C.
An electrode 113 is formed on the LT-GaAs substrate 112, and a translucent member 114 as a covering member is formed on the electrode 113 to cover the electrode 113. These are used as light emitting elements or light receiving elements.
Further, a gap 113 </ b> A is formed in the electrode 113 at a location where terahertz light is incident from the excitation optical system 31.
The concave mirror 12 includes a semi-elliptical main body 121, and the main body 121 has a reflecting surface 122 on its elliptical spherical surface. Further, the shape of the plane portion 123 of the main body portion 121 is substantially the same as the plane shape to which the light emitting / receiving element portion 11 is joined. Further, the flow path part 13 having a rectangular cross section is formed in the flat part 123.

FIG. 3 is a perspective view of the concave mirror according to the first embodiment of the present invention.
As shown in FIG. 3, a flow path portion 13 is formed in the main body 121, and the flow path portion 13 has an inflow port 131, a discharge port 132, and a staying portion 133.
In the main body 121, a staying portion 133 that is recessed in a cubic shape is formed in the flat surface portion 123. The depth of the staying portion 133 is preferably about 50 to 300 μm. This is because if the depth is too deep, the absorption of terahertz light when passing through the staying portion 133 will increase, and if it is too thin, the absorption spectrum by the sample flowing through the staying portion 133 will not be sufficient and the measurement will be insufficient.
Further, the flow path portion 13 includes an inflow port 131 that is two cylindrical perforations extending from the staying portion 133 in the planar direction of the main body portion 121, and a discharge port 132.

FIG. 4 is a schematic view showing the method for manufacturing the sensor unit in the first embodiment of the present invention.
As shown in FIG. 4, a light emitting / receiving element portion 11 on which an LT-GaAs substrate 112 and the like are formed and a concave mirror 12 are prepared (see FIG. 4A). And in the main-body part 121, the plane part 123 is processed by an etching etc., and the flow-path part 13 is formed (refer FIG. 3, FIG. 4 (B)).

Next, the GaAs substrate 111 and the main body part 121 where the flow path part 13 is formed are arranged so that the plane part 123 of the GaAs substrate 111 on the side where the LT-GaAs substrate 112 is not formed faces the plane part 123. (See FIG. 4B).
And the sensor unit 10 which has the flow-path part 13 is obtained by joining the plane of the GaAs substrate 111 and the plane part 123 (refer FIG.4 (C)).

FIG. 5 is a schematic diagram showing the flow state of the sample in the flow channel in the first embodiment of the present invention.
As shown in FIG. 5, the sample S flows from the inlet 131 and is discharged from the outlet 132. At this time, the sample S stays in the staying part 133. The staying part 133 is irradiated with the terahertz light reflected by the first light irradiation part 134A irradiated with the terahertz light incident from the gap 113A (not shown) (see FIG. 2) and the reflection surface 122 (see FIG. 2) not shown. The second light irradiation unit 134B exists, and the sample S is irradiated with terahertz light in the first light irradiation unit 134A and the second light irradiation unit 134B.

The terahertz spectrometry method according to the first embodiment of the present invention includes a flow path after a standard sample detection step of detecting an absorption spectrum obtained by flowing pure water as a standard sample through the flow path section 13 (see FIG. 5). A discharging process for completely discharging pure water from the unit 13 is performed.
Thereafter, a sample detection process is performed in which the sample S is circulated through the flow path unit 13 to detect an absorption spectrum. Then, in the spectrum analyzer 52 (see FIG. 1), an analysis processing step of performing spectrum analysis by dividing the detection signal of the absorption spectrum by the sample S by the detection signal of the absorption spectrum by water is performed.
When measuring an aqueous solution, pure water is used as a standard sample as described above. However, when using other solvents (such as alcohol or ketone), the pure solvent is measured as a standard sample, and then The solution containing the measurement object is measured, and the spectrum analysis is performed.

In the present embodiment having the above-described configuration, the following operational effects can be achieved.
(1) In the sensor unit 10 according to the present embodiment, the concave mirror 12 having the reflecting surface 122 reflects the terahertz light from the light emitting / receiving element unit 11 to the light emitting / receiving element unit 11, so that the light emitting element and the light receiving element are on the same surface. Therefore, the sensor unit 10 can have a simple configuration, and the sensor unit 10 can be downsized.
Furthermore, since the light emitting / receiving element portion 11 and the concave mirror 12 are joined, they can be further reduced in size as compared with the sensor unit 10 in which they are separated and the sample S is circulated or arranged therebetween.

(2) In the sensor unit 10 of the present embodiment, the light emitting / receiving element portion 11 and the concave mirror 12 are joined to each other, and the flow path portion 13 of the sample S is formed between them. The terahertz light can be emitted from the LT-GaAs substrate 112 while passing through the sample S, and the sample S can be transmitted and incident on the LT-GaAs substrate 112.
That is, there is only the sample S in the GaAs substrate 111, the main body 121, and the flow path 13 on the optical path of the terahertz light from the LT-GaAs substrate 112 to the incident on the LT-GaAs substrate 112. Become.
For this reason, terahertz light is not absorbed by the atmosphere or space. Therefore, only the absorption spectrum derived from the sample S can be detected by the light emitting / receiving element unit 11, and the sensor unit 10 of the present embodiment can have high measurement accuracy.

(3) The sensor unit 10 forms the flow path portion 13 by processing the flat portion 123 by etching or the like in the concave mirror 12.
For this reason, the flow path part 13 can be formed between the light emitting / receiving element part 11 and the concave mirror 12 only by etching the flat part 123.
Therefore, the sensor unit 10 can have a simple configuration and can be easily manufactured.

(4) An electrode 113 is formed on the LT-GaAs substrate 112, and a translucent member 114 is formed on the electrode 113 to cover the electrode 113.
For this reason, the short circuit of the electrode 113 can be prevented. Further, deterioration of the electrode 113 due to contact with outside air can be prevented.

(5) The flow path portion 13 is provided with the inlet 131 and the outlet 132 diagonally so that the staying portion 133 can be filled with the sample S.
Since the sample S can be always circulated through the first light irradiation unit 134A and the second light irradiation unit 134B, the absorption spectrum derived from the sample S can be detected stably.

(6) Since the terahertz spectrometer 1 includes the spectroscopic processing unit 50 that performs analysis processing from the signal detected by the LT-GaAs substrate 112, analysis and analysis of the obtained detection signal are performed simultaneously with the terahertz spectroscopic measurement. It can be carried out.
Therefore, terahertz spectroscopy measurement and its analysis and analysis can be performed at a time, so that a measurement result can be obtained in a short time.

(7) In the terahertz spectroscopic measurement of the present embodiment, pure water is circulated through the flow path portion 13 to detect the absorption spectrum, and then the pure water is completely discharged from the flow path portion 13. Thereafter, the sample S is circulated through the flow path portion 13 to detect the absorption spectrum. Then, the spectrum analysis is performed by dividing the detection signal of the absorption spectrum by the sample S by the detection signal of the absorption spectrum by pure water.

  For this reason, the absorption spectrum by pure water is detected, and then the absorption spectrum by sample S is detected. Since the measurement and evaluation are performed by dividing the detection signal of the absorption spectrum by the sample S by the detection signal of the absorption spectrum by the standard sample, stable measurement accuracy can be ensured.

Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a schematic diagram showing a method for manufacturing a sensor unit according to the second embodiment of the present invention.
The second embodiment is different from the first embodiment in that a spacer 14 is used instead of providing the flow passage portion 13 in the main body 121, and other configurations are the same as those in the first embodiment. is there.

As shown in FIG. 6, a light emitting / receiving element portion 11 on which an LT-GaAs substrate 112 and the like are formed, and a concave mirror 12 are prepared.
The spacer 14 is disposed between the light emitting / receiving element portion 11 and the concave mirror 12, and the spacer 14 is sandwiched between the light emitting / receiving element portion 11 and the concave mirror 12, whereby the sensor unit 10 having the flow path portion 13 is obtained.

Therefore, in 2nd Embodiment, there can exist an effect similar to the effect (1), (2), (4)-(7) of 1st Embodiment. Furthermore, the following effects can be obtained.
(8) In the sensor unit 10 of this embodiment, the flow path portion 13 is partitioned by using the spacer 14.
For this reason, since the flow path portion 13 is partitioned by the spacer 14, the spacer 14 is sandwiched between the light emitting / receiving element portion 11 and the concave mirror 12 to join the light emitting / receiving element portion 11 and the concave mirror 12. The flow path portion 13 can be partitioned.
Therefore, in 2nd Embodiment, the sensor unit 10 can be set as a simple structure, and also the said sensor unit 10 can be manufactured easily.

A third embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a schematic diagram showing a sensor unit in the third embodiment of the present invention.
The third embodiment is different from the first embodiment in the configuration of the excitation optical system 31 and the probe optical system 32, and the other configurations are the same as those in the first embodiment.
The translucent member 114 is provided with an attachment portion 114A to which a flexible optical fiber F is attached. The mounting portion 114A is a hole penetrating in the thickness direction of the translucent member 114, and the optical fiber F is detachably mounted and fixed by conducting the tip of the optical fiber F through the hole.

Therefore, in 3rd Embodiment, there can exist an effect similar to the effect (1)-(7) of 1st Embodiment. Furthermore, the following effects can be obtained.
(9) In the present embodiment, the translucent member 114 is provided with attachment portions 114A to which the optical fibers F having flexibility are attached, and the tips of the optical fibers F having flexibility are attached to the attachment portions 114A. The optical fiber F is attached and fixed so that it can be engaged and disengaged.

For this reason, the optical fiber F can be easily attached with a simple configuration. By attaching the optical fiber F to the attachment portion 114A, the excitation light or the probe light is guided to the light-emitting / receiving element portion 11 or the concave mirror 12 by the optical fiber F, so that the excitation optical system 31 or the probe optical system 32 is connected to a mirror or the like. There is no need to bend by reflection, and by bending the optical fiber F, these optical paths can be freely bent.
Therefore, in the third embodiment, a configuration for changing the optical path like the fixed reflecting mirror 43 is not required, and the positional relationship between the pulse light source 100 (see FIG. 1) and the sensor unit 10 can be set freely. Therefore, the terahertz spectrometer 1 (see FIG. 1) can have a simple configuration, and can be easily downsized.

FIG. 8 is a schematic diagram showing a sensor unit in the fourth embodiment of the present invention.
The fourth embodiment is different from the first embodiment in the configuration of the flow path portion, and the other configurations are the same as those in the first embodiment.
The first concave body 15 as the reflective element portion is a translucent semi-ellipsoid having a first concave surface portion 152, and has a first flat surface portion 153 at a position facing the first concave surface portion 152. The first flat surface portion 153 is joined to the light emitting / receiving element portion 11 so that the light emitting / receiving element portion 11 and the first concave body 15 are integrally formed.
The second concave surface body 16 is provided outside the first concave surface portion 152. The second concave body 16 has a rectangular parallelepiped shape, and is a translucent member whose one plane is cut into a semi-elliptical shape. The spherical surface of the second concave surface portion 162 cut into a semi-elliptical shape is formed to have a larger radius than the first concave surface portion 152. For this reason, when the first concave body 15 and the second concave body 16 are joined together, a gap is formed between the first concave surface portion 152 and the second concave surface portion 162. This gap can be used as the flow path portion 13.

FIG. 9 is a schematic diagram showing an optical path of an evanescent wave in the fourth embodiment of the present invention.
As shown in FIG. 9, the terahertz light is incident on the flow path portion 13 at an angle at which it is totally reflected. At this time, the terahertz light is totally reflected by the evanescent effect at the interface of the flow path portion. In the flow path portion 13, the evanescent wave EW is reflected again to the first concave body 15 while passing through the sample S. For this reason, the terahertz light after total reflection is incident on the LT-GaAs substrate 112 to detect the absorption spectrum.
As shown in FIG. 9B, it is preferable that the terahertz light is incident on the flow path portion 13 at the same angle because the depth of the evanescent wave that enters the sample S becomes constant.

  Therefore, in 4th Embodiment, there can exist an effect similar to the effect (1), (2), (4)-(7) of 1st Embodiment. Furthermore, the following effects can be obtained.

(10) In the sensor unit 10 of the present embodiment, the flow path portion 13 is formed by providing the second concave body 16. For this reason, it is not necessary to perform etching or the like in order to form the flow path portion 13 in the first flat portion 153 of the first concave body 15. Therefore, the sensor unit of this embodiment can be easily manufactured.
Furthermore, in the present embodiment, the terahertz light is incident from the first concave body at the angle at which it is totally reflected in the flow path portion 13 and is totally reflected. Therefore, it is not necessary to provide a reflective surface on the second concave body 16. For this reason, the 1st concave body 15 can be made into a simple structure.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
In 4th Embodiment, although the 1st concave body 15 and the 2nd concave body 16 were used, it is not restricted to this. For example, the sensor unit 10 may be configured as shown in FIG. 10 and FIG. 11 as long as the terahertz light is totally reflected in the flow path portion 13 and the absorption spectrum derived from the sample S can be detected by the evanescent wave EW. Either is acceptable.
In the sensor unit 10 (this figure) of FIGS. 10 and 11, since the terahertz light is incident on the flow path portion 13 at the same angle, the penetration depth of the evanescent wave EW that passes through the sample S is constant.
For this reason, since the absorption spectrum derived from the sample S is stabilized, it can be measured with high accuracy.
Further, in the present embodiment, since the sample S is dropped and measured on the sensor unit, it is not necessary to inject the sample S into the flow path. For this reason, it becomes a very convenient measuring device.

  Further, for example, the flow path portion 13 is formed in the concave mirror 12, but the present invention is not limited thereto, and the flow path portion 13 may be formed in the light emitting / receiving element portion, or the flow paths are formed in both the light emitting / receiving element portion and the concave mirror 12. The portion 13 may be formed.

  Although the optical fiber F is attached to the attachment portion 114A of the translucent member 114, the present invention is not limited to this, and the tip of the optical fiber F is directed toward the light guide hole 113A so that excitation light and probe light enter the light guide hole 113A. You may leave it away.

  The present invention can be used for various optical measurement devices in addition to a terahertz spectrometer.

  DESCRIPTION OF SYMBOLS 1 ... Terahertz spectroscopy measuring apparatus, 10 ... Sensor unit, 11 ... Light-emitting / receiving element part, 12 ... Concave mirror, 122 ... Reflective surface, 13 ... Channel part, 14 ... Spacer, 15 ... First concave body (reflective element part), 16 ... 2nd concave body (reflection element part), 30 ... Laser beam, 50 ... Spectral processing part (analysis means), 100 ... Pulse light source (laser oscillator), 112 ... LT-GaAs substrate (light emitting element, light receiving element), 113 ... Electrode, 114 ... Translucent member (cover member), 114A ... Mounting portion, F ... Optical fiber, S ... Sample

Claims (8)

A light emitting element having a light emitting element that generates terahertz light; a light receiving element having a light receiving element that receives the terahertz light and detects a detection signal; and the light receiving element that emits the terahertz light emitted from the light emitting element. A reflective element portion having a reflective surface that reflects toward the surface,
The light emitting element part, the light receiving element part and the reflective element part are integrally joined,
A sensor unit, characterized in that a flow path part for circulating a sample is formed between optical paths between the light emitting element part and the light receiving element part. The sensor unit according to claim 1,
The sensor unit, wherein the light emitting element part and the light receiving element part are light emitting and receiving element parts in which the light emitting element and the light receiving element are provided on the same surface. The sensor unit according to claim 1 or 2,
The sensor unit, wherein the flow path part is formed in at least one of the light emitting element part, the light receiving element part, and the reflecting element part. The sensor unit according to any one of claims 1 to 3,
A sensor unit, wherein the flow path section is partitioned by a spacer. A light emitting element unit having a light emitting base element for generating terahertz light, a light receiving element unit having a light receiving element for receiving the terahertz light and detecting a detection signal, and a reflective element unit having a flow path unit,
The light emitting element part, the light receiving element part and the reflective element part are integrally joined,
The terahertz light is emitted from the light emitting element portion, is incident at a total reflection angle in the flow path portion, is totally reflected, and is incident on the light receiving element portion. The sensor unit according to any one of claims 1 to 5,
The sensor unit, wherein the light emitting / receiving element part is provided with an optical fiber for guiding laser light to the light emitting element part on the opposite side of the joint surface between the light emitting / receiving element part and the reflecting element part. The sensor unit according to any one of claims 1 to 6,
A laser oscillator for irradiating the light emitting element portion and the light receiving element portion with a laser beam;
And a terahertz spectrometer, comprising: an analysis unit that performs an analysis process using the detection signal. A terahertz spectrometry method using the terahertz spectrometer according to claim 7,
A standard sample detection step of detecting the detection signal by allowing a standard sample to flow into the flow path portion;
A discharge step of discharging the standard sample from the flow path portion;
A sample detection step of detecting the detection signal by allowing the sample to flow into the flow path portion;
A terahertz spectroscopic measurement comprising: an analysis processing step of analyzing the sample by comparing the detection signal obtained in the standard sample detection step with the detection signal obtained in the sample detection step Method.

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