WO2006064653A1

WO2006064653A1 - Terahertz photodetector, method for detecting terahertz light, and terahertz imaging system

Info

Publication number: WO2006064653A1
Application number: PCT/JP2005/021764
Authority: WO
Inventors: Naoki Tsumura; Hiromichi Akahori
Original assignee: Tochigi Nikon Corporation; Nikon Corporation
Priority date: 2004-12-16
Filing date: 2005-11-28
Publication date: 2006-06-22
Also published as: JP2006170822A

Abstract

Disclosed is a terahertz photodetector comprising a first antenna (21A) for detecting a terahertz light (T2) polarized in a first direction (X direction), and a second antenna (21B) for detecting a terahertz light (T2) polarized in a second direction (Y direction) which is different from the first direction (X direction).

Description

Specification

Terahertz photodetector, terahertz light detection method, and terahertz imaging device

Technical field

The present invention relates to a terahertz photodetector, a terahertz light detection method, and a terahertz imaging device.

Background art

[0002] Various measuring devices that use terahertz light irradiate the sample with terahertz pulse light in the frequency range of approximately 0.01 x 10 ^{12 to} 100 x 10 ¹² hertz (0.01 to: LOOTHz). Then, by detecting the transmitted light that has passed through the sample or the reflected light that has been reflected from the sample, the electrical characteristics and component concentration of the sample are measured. Conventionally, an optical switch element is known as a detector for detecting a terahertz pulse light of a sample force. This optical switch element has a structure in which a photoconductive film is formed on a semiconductor substrate, and a single optical switch portion such as a micro dipole antenna cover is provided on the photoconductive film. By irradiating the optical switch with probe pulse light together with terahertz pulse light, it is possible to detect terahertz pulse light having a polarization component parallel to the direction of the antenna. (For example, see Patent Document 1).

[0003] Patent Document l: WO00Z079248 (Page 12, Figure 2 (B))

Disclosure of the invention

Problems to be solved by the invention

[0004] In general, the transmitted terahertz light transmitted through the sample or the reflected terahertz light reflected by the sample may have two polarization components whose polarization directions are orthogonal to each other. Since the optical switch element of Patent Document 1 has only one antenna direction, it cannot detect light having a polarization component orthogonal to the antenna direction. Therefore, there is a problem that it is impossible to accurately measure the polarization state of the terahertz light of the sample force.

Means for solving the problem

A terahertz photodetector according to the present invention includes a first antenna that detects terahertz light polarized in a first direction and a tera polarized in a second direction different from the first direction. Detect ruth light And a second antenna.

The first and second antennas are preferably arranged so that the antenna directions are orthogonal to each other.

Further, each of the first and second antennas is a dipole antenna composed of a pair of conductive films disposed on the photoconductive film with a space therebetween, and a pair of conductive films provided on the first antenna. Are arranged opposite to each other along a first direction across a predetermined region, and a pair of conductive films provided on the second antenna are arranged opposite to each other along a second direction different from the first direction across the predetermined region. You may do it. Note that it is preferable that the distance between the pair of conductive films provided for the first antenna and the distance between the pair of conductive films provided for the second antenna are set to be equal.

A terahertz light detection method according to the present invention is a terahertz light detection method using the terahertz light detector according to any one of claims 1 to 3, wherein the first and second antennas On the other hand, terahertz light is respectively irradiated, and two polarization components having different polarization directions of terahertz light are detected by the first antenna and the second antenna. Also, the irradiation region including at least a predetermined region is irradiated with terahertz light, and two polarization components having different polarization directions of the terahertz light are detected simultaneously by the first antenna and the second antenna. Also good!

The terahertz spectrometer according to the present invention is described in any one of claims 1 to 4 in which the terahertz light irradiation means for irradiating the sample with terahertz light and the terahertz light having the sample force are incident. And a calculating means for calculating physical property information of the sample on the basis of the detection signals of the first and second antennas on which the sample-powered terahertz light is incident. Features.

The second aspect of the terahertz spectrometer according to the present invention is the terahertz light irradiating means for irradiating the sample with terahertz light, and the terahertz light from the sample is incident. A terahertz light detector according to claim 1, a measurement circuit for measuring detection signals of the first and second antenna forces on which the terahertz light of the sample force is incident, and the first and second antennas The physical property information of the sample is calculated based on the switching means for selectively inputting one of each detection signal from the sensor to the measurement circuit and the detection signal selected by the switching means. And an arithmetic means for performing the processing.

The terahertz imaging apparatus according to the present invention is the terahertz light irradiating means for irradiating the sample with terahertz light, and the terahertz light from the sample is incident. A terahertz light detector, a moving mechanism that moves the sample two-dimensionally to change the irradiation position of the terahertz light on the sample, and the first and second terahertz light from the sample is incident And a calculation means for calculating two-dimensional physical property information of the sample based on each detection signal of the antenna.

The invention's effect

[0006] According to the present invention, since the first and second antennas capable of detecting the terahertz light having different polarization directions are provided, the change in the polarization state of the terahertz light by the sample can be measured more accurately. It becomes possible.

Brief Description of Drawings

FIG. 1 is a schematic configuration diagram of a terahertz imaging apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing the structure of the terrahertz light generating element 10.

FIG. 3 (a) is a perspective view schematically showing the structure of the terahertz light detection element 20, and FIG. 3 (b) is an enlarged view of the antenna portion shown in FIG. 3 (a).

4 is a diagram showing a terahertz light detection element 20 and a measurement circuit 25. FIG.

FIG. 5 is a diagram showing a modification of the measurement circuit.

FIG. 6 is a view showing a modification of the terahertz light detecting element 20.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a terahertz imaging apparatus according to the present invention. The terahertz imaging device 100 emits a terahertz pulsed light T1 by irradiating the pulsed light L2, a laser light source 1 that emits the pulsed light L1, a beam splitter 2 that divides the pulsed light L1 into pulsed light L2 and L3 A terahertz light generating element 10 and a terahertz light detecting element 20 for detecting terahertz pulsed light T2 that has passed through the sample S are provided. The terahertz imaging device 100 detects terahertz light using the well-known time-series terahertz light detection method, and it moves the movable mirror 5 that changes the optical path length of the pulsed light L3 and the sample S in two dimensions. Move the two-dimensional drive mechanism 8 I have.

Furthermore, the terahertz imaging apparatus 100 is provided with a measurement circuit 25 and a control 'arithmetic processing unit 9. The measurement circuit 25 measures the photocurrent (detection signal) of the terahertz light detection element 20. The control / arithmetic processing unit 9 performs various calculations based on the measurement results of the measurement circuit 25. For example, 2D physical property information of a sample is calculated. The calculation result is displayed on the display 9a. The control / arithmetic processing unit 9 also controls the linear drive mechanism 6 and the two-dimensional drive mechanism 8 that move the movable mirror 5 in the A direction.

[0010] For the laser light source 1 that emits the pulsed light L1, for example, a femtosecond pulse laser is used. The pulsed light L1 is linearly polarized with a center wavelength of about 780 to 830 nm (near infrared region), and has a pulse repetition period of several kHz to 100 MHz and a pulse width of 10 to 150 fs.

Next, the operation of the terahertz imaging apparatus 100 will be described. The pulsed light L 1 emitted from the laser light source 1 is divided by the beam splitter 2. One of the divided pulse lights L2 is incident on the terahertz light generating element 10 as pump light (excitation light). Details of the terahertz light generating element 10 will be described later. The terahertz light generating element 10 is excited by the pulsed light L2, and generates the terahertz pulsed light T1. Note that a condensing lens may be disposed between the beam splitter 2 and the terahertz light generating element 10, and the light bundle of the pulsed light L2 may be narrowed by the condensing lens.

[0012] Terahertz pulsed light T1 is light having a frequency of 0.01 X 10 ^{12 to} 100 X 10 ¹² hertz (0.01 TH z to 100 THz), and follows the direction of the antenna of the terahertz light generating element 10. Polarized light. This terahertz light T1 is reflected and collected by the curved mirror 3 and enters one point of the sample S.

[0013] Terahertz pulsed light T2 transmitted through one point of sample S is light including physical property information of sample S, is reflected by curved mirror 4, and is incident on terahertz light detecting element 20. The terahertz light detection element 20 is irradiated with the pulsed light L3 divided by the beam splitter 2 as probe light. When terahertz pulsed light T2 is incident on the terahertz light detecting element 20, an electric field is generated in the antenna portion, and when the probe light is irradiated on that portion, a photocurrent corresponding to the electric field intensity of the terahertz pulsed light T2 is generated. Flowing. [0014] From the current value of the photocurrent, that is, the electric field strength value, the control and calculation processing unit 9 calculates the electrical characteristics, impurity concentration, and the like of the sample based on a predetermined theoretical formula. These measured values, two-dimensional images, etc. are displayed on the display 9a as necessary. In actual measurement, the sample S, which is not only the sample measurement described above, is also placed in the optical path of the terahertz pulsed light T1, and the reference measurement performed in the sample measurement is performed from both the sample measurement and the reference measurement results. Get the physical property value of S.

[0015] The pulsed light L3 used as the probe light is incident on a movable mirror 5 such as two or three reflecting mirrors that can move in the A direction indicated by the arrow in FIG. After the pulsed light L3 is reflected by the movable mirror 5, the optical path is bent by the reflecting mirror 7 and enters the terahertz light detecting element 20. By moving the movable mirror 5 in the A direction by the linear drive mechanism 6, the optical path length of the pulsed light L3 can be changed according to the amount of movement of the movable mirror 5. As a result, the time for the pulsed light L 3 to reach the terahertz light detecting element 20 can be delayed.

[0016] As described above, the electric field strength of the terahertz pulse light T2 detected by the terahertz light detection element 20 is measured while changing the delay time of the pulse light L3 incident on the terahertz light detection element 20. Thus, time series terahertz spectroscopy becomes possible. Instead of inserting the movable mirror 5 into the optical path of the probe light (pulse light L3) and delaying the probe light time, the movable mirror 5 is inserted into the optical path of the pump light (pulse light L2) to generate a terahertz pulse. A time delay operation may be performed on the optical T1.

Next, details of the terahertz light generating element 10 will be described with reference to FIG. The terahertz light generating element 10 includes a semiconductor substrate 13 made of, for example, a semi-insulating GaAs substrate, and a hemispherical lens 14. A photoconductive film 12 is formed on the semiconductor substrate 13, and a metal conductive film 11 that functions as an antenna is formed on the photoconductive film 12. The photoconductive film 12 is formed of, for example, a thin film of GaAs or amorphous silicon. The hemispherical lens 14 is bonded to the light emitting surface side of the semiconductor substrate 13 in order to efficiently extract the generated terahertz light to the outside. Transmit infrared light such as. A hemispherical lens may be used instead of the hemispherical lens 14. Here, the hemispherical lens or the superhemispherical lens is representatively referred to as a hemispherical lens 14.

The conductive film 11 is a metal film that is patterned on the photoconductive film 12. In the form, it is patterned in the shape of a dipole antenna. The two parallel transmission lines are narrow and the part facing each other through the gap is the antenna part described above, which functions as a dipole antenna. As shown in FIG. 2, when a bias voltage Vb is applied to the conductive film 11 of the dipole antenna pattern by the power supply circuit 15 and the region B on the conductive film 11 formation surface is irradiated with the pulsed light L2, the terahertz pulsed light is emitted. T1 occurs. Region B is a region that almost includes the gap of the antenna section. The generated terahertz pulsed light T1 passes through the hemispherical lens 14 and is emitted to the outside.

Next, the terahertz light detection element 20 will be described with reference to FIG. In the conventionally known terahertz imaging apparatus and terahertz light spectroscopic apparatus, the terahertz light detecting element and the terahertz light generating element use the same element. However, in the present invention, even when the polarization state of the terahertz light changes, for example, by passing through the sample, the respective polarization components in the X direction and the Y direction included in the terahertz light can be accurately measured. Thus, an element having a structure different from that of the terahertz light generating element 10 is used as the terahertz light detecting element 20.

Specifically, the terahertz light detection element 20 functions as a semiconductor substrate 23, a photoconductive film 22 formed on the semiconductor substrate 23, and a pair of antennas formed on the photoconductive film 22. A metal conductive film 21 and a hemispherical lens 24 are provided. Note that a super hemispherical lens may be used instead of the hemispherical lens 24. Here, the hemispherical lens or super hemispherical lens is referred to as the hemispherical lens 24.

As shown in FIG. 3 (a), the conductive film 21 is composed of four L-shaped conductive films.

Then, a pair of dipole antennas 21A and 21B whose antenna directions are orthogonal to each other are formed. As shown in Fig. 3 (b), the dipole antenna 21A is composed of two L-shaped patterns Al and A2, and the dipole antenna 21B is composed of two L-shaped patterns Bl and B2. The L-shaped patterns Al and A2 and the L-shaped patterns Bl and B2 face each other through a narrow gap in the terahertz light incident region C, and these facing portions are respectively the dipole antennas 21A and 21B. Functions as an antenna. The antenna direction of the dipole antenna 21A is the X direction in FIG. 3, and the antenna direction of the dipole antenna 21B is the Y direction. FIG. 4 is a diagram showing the terahertz light detection element 20 and the measurement circuit 25 shown in FIG. 25a and 25b are ammeters provided in the measurement circuit 25. The L-shaped patterns Al and A2, which are the two L-shaped transmission lines constituting the dipole antenna 21A, are connected to the ammeter 25a. ing. On the other hand, the L-shaped patterns Bl and B2, which are the two L-shaped transmission lines constituting the dipole antenna 21B, are connected to the ammeter 25b. In FIG. 3, the ammeter 25b connected to the dipole antenna 21B is not shown. The antenna portion 31a of the dipole antenna 21A and the antenna portion 31b of the dipole antenna 21B are orthogonal to each other and both have an area covering the terahertz light incident region C.

[0023] When the terahertz pulsed light T2 that has passed through the sample S is incident on the terahertz light incident area C, if the terahertz pulsed light T2 is light polarized in the X direction, it is detected by the dipole antenna 21A and applied to the tera If the rutz pulse light T2 is polarized in the Y direction, it will be detected by the dipole antenna 21B. That is, the pair of dipole antennas 21 A and 21 B detect the terahertz pulse light T2 corresponding to two orthogonal polarization components included in the terahertz light T2.

[0024] The dipole antennas 21A and 21B have, for example, the gap length G force / zm of the antenna portions 31a and 31b, the pattern width of the conductive film 21 is 4 μm, and the position force of the antenna portion of each pattern is also bent. The length d is set to 10-20 / ζ πι. In general, the gap length G and the pattern width of the conductive film 21 are set slightly narrower than the diameter of the region C, and the pattern length d of the antenna section is set according to the frequency band to be detected by the terahertz light. The

[0025] In particular, by setting the gap length G between the antenna unit 31a and the antenna unit 31b to be equal, it is possible to detect light of both the X-direction polarization component and the Y-direction polarization component under the same conditions. In the present embodiment, the antenna unit 3la includes a transmission line composed of a pair of conductive film patterns Al and A2, and the antenna unit 31b includes a transmission line composed of a pair of conductive film patterns Bl and B2. In each of the antenna portions 31a and 31b, each pair of transmission lines is opposed to each other with the same gap length. The opposing direction of the transmission line in the antenna units 31a and 31b is the direction of each antenna.

[0026] The operation of the terahertz light detecting element 20 configured as described above will be described with reference to Figs. To do. As shown in FIG. 3, the terahertz pulsed light T2 is incident on the terahertz light detecting element 20 from the hemispherical lens 24 side, and is collected in the region C on the conductive film 21 forming surface by receiving the refractive action of the hemispherical lens 24. Shine. On the other hand, the pulse light L3 as the probe light irradiates the region C with the side force on which the conductive film 21 of the terahertz light detection element 20 is formed, contrary to the terahertz pulse light T2. At this time, if the polarization direction of the terahertz pulse light T2 coincides with the antenna direction of the dipole antenna 21A, the photoelectric current Im generated by the electric field of the terahertz pulse light T2 flows to the dipole antenna 21A, and this electric field strength is The corresponding photocurrent Im is measured by an ammeter 25 a provided in the measurement circuit 25. In FIG. 3, the circuit portion provided with the resistor and the amplifier indicated by the arrow constitutes the ammeter 25a.

[0027] The relationship between the polarization direction of the terahertz pulsed light T1 and the polarization direction of the terahertz pulsed light T2 will be described with reference to FIG. 2 and FIG. When the antenna direction of the dipole antenna 11 formed in the terahertz light generating element 10 is arranged in the X direction in FIG. 2, the terahertz light generating element 10 is a terahertz pulsed light having a polarization component in the X direction. T1 is emitted. The sample S is irradiated with the terahertz pulse light T1 polarized in the X direction, and the terahertz pulse light T2 transmitted through the sample S is incident on the terahertz light detection element 20.

If the terahertz pulsed light T2 is also polarized in the X direction, the terahertz light detecting element 20 is detected by the dipole antenna 21A whose antenna direction is the X direction. On the other hand, since the antenna direction of the dipole antenna 21B is the Y direction, the terahertz pulse light T2 polarized in the X direction is not detected. Thus, the antenna direction of the dipole antenna 11 formed on the terahertz light generating element 10 and the antenna direction of the dipole antenna 21A formed on the terahertz light detecting element 20 are aligned in the same direction. The terahertz pulsed light T2 polarized in the X direction can be detected.

[0029] However, in actual terahertz spectroscopic measurement and terahertz imaging, terahertz pulsed light T2 that has passed through the sample S is not always the only polarization component in the X direction. For example, if the sample S generates an optical rotation that has both a polarization component in the X direction and a polarization component in the Y direction, the dipole antenna 21A alone cannot detect the polarization component in the Y direction. For this reason, it is impossible to distinguish whether the change in the polarization component in the X direction detected by the dipole antenna 21A is due to the optical rotation or not due to the absorption of the sample S. However, as shown in FIG. 4, in this embodiment, one terahertz light detection element 20 is provided with a pair of dipole antennas 21A and 21B whose antenna directions are orthogonal to each other. Therefore, the polarization components in the X and Y directions of the terahertz pulse light T2 can be detected independently, and accurate detection data can be obtained. In addition, since the antenna portions 31a and 31b of the dipole antennas 21A and 21B are arranged so as to cover the terahertz light incident area C, the X and Y directions of the terahertz pulse light T2 are arranged. Can be detected simultaneously.

[0031] For example, in a terahertz light detecting element that does not have a force as a unidirectional dipole antenna, it is necessary to rotate the terahertz light detecting element around the optical axis in order to detect both polarization components. It was. On the other hand, in the present embodiment, it is not necessary to rotate the terahertz light detection element 20, and it is not necessary to provide a rotation mechanism.

[0032] Next, two-dimensional measurement of the sample S by the terahertz imaging apparatus according to the present embodiment will be described. As shown in FIG. 1, in the terahertz imaging apparatus 100 according to the present embodiment, the sample S is moved two-dimensionally by the two-dimensional drive mechanism 8, thereby generating the terahertz pulsed light T1 on the sample S. Two-dimensional scanning is possible. As a result, the terahertz pulsed light T2 that has passed through each point of the scanning region on the sample S is detected by the terahertz light detecting element 20. Then, based on the photocurrent Im measured by the measurement circuits 25a and 25b during the two-dimensional scanning, a predetermined calculation is performed by the control / calculation processing unit 9, thereby distributing the electrical characteristics and impurity concentration of the sample S. Is measured. These distributions are synthesized as a two-dimensional image by the control processing unit 9, and the synthesized image is displayed on the display 9a.

FIG. 5 is a diagram showing a modification of the measurement circuit 25 (25a, 25b), and corresponds to FIG. In FIG. 5, instead of the measurement circuit 25 (25a, 25b) of FIG. 4, a measurement circuit 25A having a switching switch 26 and an ammeter 27 is provided. Two L-shaped transmission line patterns Al and A2 of dipole antenna 21A are connected to terminals Tal and Ta2 of switching switch 26, and two L-shapes of dipole antenna 21B are connected to terminals Tbl and Tb2. Type transmission line patterns B1 and B2 are connected. Terminals Tel and Tc2 of switch 26 are connected to ammeter 27. [0034] When the switching switch 26 is driven to connect the terminals Tal and Tel, and the terminal Ta2 and the terminal Tc2 are connected, the antenna section 31a of the dipole antenna 21A becomes in a detectable state. Conversely, by connecting the terminal Tbl and the terminal Tel, and connecting the terminal Tb2 and the terminal Tc2, the antenna portion 31b of the dipole antenna 21B can be detected. As a result, by switching the switching switch 26, the polarization component in the X direction and the Y direction of the terahertz pulse light T2 can be measured in order with one ammeter 27.

In the terahertz imaging apparatus 100 according to the present embodiment, one terahertz light detecting element (terahertz light detector) 20 has a pair of antennas (dipole antennas 21A and 21B) having different antenna directions. ) Is provided, the two-dimensional distribution state such as the electrical characteristics and impurity concentration of sample S can be obtained easily and accurately, and can be easily imaged as a two-dimensional image. .

As described above, according to the present invention, a pair of antennas are provided in one terahertz light detecting element (terahertz light detector), that is, each of the antennas corresponds to the polarized light to be detected. The present invention is characterized in that a pair of antenna portions having different antenna orientations are provided, and the present invention is not limited to the above-described embodiment as long as the characteristics are not impaired. For example, a pair of antenna portions having different antenna orientations may overlap in position as in the terahertz light detection element 20 of the present embodiment, and may be positioned apart as shown in FIG. It ’s okay to go.

[0037] Note that the antenna directions of the pair of antenna units do not necessarily have to be orthogonal. In other words, if a pair of antennas having different antenna directions are provided, two orthogonal polarization components can be obtained by calculation using the detection results.

In the terahertz light detection element 20 A shown in FIG. 6, the X-direction polarization detection antenna 121 A and the Y-direction polarization detection antenna 121 B are independently arranged at different positions on the conductive film 122. An antenna unit 131a that detects polarized light in the X direction and an antenna unit 131b that detects polarized light in the Y direction are provided. In this case, the terahertz light detecting element 20A is arranged so that the terahertz light incident area C on which the terahertz pulse light T2 and the probe light L3 are incident and the antenna parts 131a and 131b overlap according to the polarization component to be detected. If you move it with an actuator, etc. In addition, the present invention is not limited to the terahertz imaging apparatus 100 but can be applied to a terahertz spectrometer using terahertz light. Furthermore, the present invention is not limited to detecting transmitted terahertz light transmitted through a sample, but can also be applied to detecting reflected terahertz light reflected by a sample. For example, terahertz light is incident on the sample surface at an angle, and the reflected terahertz light reflected by the sample is received by the photodetector, so that the terahertz light generating element 10 and A terahertz light detection element 20 is arranged.

[0040] The disclosure content of the following priority application is hereby incorporated by reference.

Japanese patent application 2004 No. 364175 (filed December 16, 2004)

Claims

The scope of the claims

[1] Terahertz photodetectors

A first antenna for detecting terahertz light polarized in a first direction;

A second antenna for detecting terahertz light polarized in a second direction different from the first direction.

[2] In the terahertz photodetector according to claim 1,

The first and second antennas are arranged so that the antenna directions are orthogonal to each other.

[3] In the terahertz photodetector according to claim 1 or 2,

Each of the first and second antennas is a dipole antenna composed of a pair of conductive films disposed on the photoconductive film so as to face each other with a space therebetween.

[4] In the terahertz photodetector according to claim 3,

The pair of conductive films provided on the first antenna are disposed to face each other along the first direction with the predetermined region interposed therebetween, and the pair of conductive films provided on the second antenna sandwich the predetermined region. And are arranged opposite to each other along a second direction different from the first direction.

[5] In the terahertz photodetector according to claim 3 or 4,

The distance between the pair of conductive films provided on the first antenna is set equal to the distance between the pair of conductive films provided on the second antenna.

[6] A terahertz light detection method using the terahertz light detector according to any one of claims 1 to 3,

The first and second antennas are respectively irradiated with terahertz light, and two polarization components having different polarization directions of the terahertz light are detected by the first antenna and the second antenna.

[7] A terahertz light detection method using the terahertz light detector according to claim 4, wherein the irradiation region including at least the predetermined region is irradiated with terahertz light,

Two polarized components having different polarization directions of the terahertz light are detected simultaneously by the first antenna and the second antenna.

[8] Terahertz spectrometer

Terahertz light irradiation means for irradiating the sample with terahertz light; and The terahertz light detector according to any one of claims 1 to 5, wherein the terahertz light having the sample force is incident thereon,

And a calculation means for calculating physical property information of the sample based on the detection signals of the first and second antenna forces on which the terahertz light of the sample force is incident.

[9] Terahertz spectrometer

Terahertz light irradiation means for irradiating the sample with terahertz light; and

The terahertz light detector according to any one of claims 1 to 5, wherein the terahertz light having the sample force is incident thereon,

A measurement circuit for measuring the detection signals of the first and second antenna forces on which the terahertz light having the sample force is incident; and

Switching means for selectively inputting one of the detection signals of the first and second antenna forces to the measurement circuit;

Computing means for computing physical property information of the sample based on the detection signal selected by the switching means.

[10] Terahertz imaging equipment

A moving mechanism for moving the sample two-dimensionally and changing the irradiation position of the terahertz light on the sample;

Computation means for computing two-dimensional physical property information of the sample based on the detection signals of the first and second antennas on which the terahertz light of the sample force is incident.