Photoelectric conversion device and photoelectric conversion method

Abstract

A photoelectric conversion device is provided with an electron emitter including a metasurface that emits electrons in response to incidence of electromagnetic waves. The metasurface includes a plurality of photoelectric conversion units having sensitivity to electromagnetic waves having mutually different wavelength regions. The plurality of photoelectric conversion units respectively include patterns having mutually different configurations.

Description

Technical Field

[0001] One aspect of the present invention relates to a photoelectric conversion device and a photoelectric conversion method. Background Technology

[0002] There are generally four types of electron emission: thermionic emission, photoelectric emission, secondary emission, and field emission. Thermionic emission is achieved by heating electrodes. Photoelectric emission is achieved by applying photons. Secondary emission is achieved by bombarding electrons at the speed of light. Field emission is achieved in the presence of an electrostatic field. U.S. Patent Application Publication No. 2016 / 0216201 describes an electromagnetic wave detection system for detecting electromagnetic waves. The system includes a photoelectric conversion device that converts electromagnetic waves into electrons. The photoelectric conversion device is equipped with an electron emitter having a metamaterial structure. The system detects electromagnetic waves entering the electron emitter. Summary of the Invention

[0003] The electron emitter of the aforementioned photoelectric conversion device emits electrons in response to the incidence of electromagnetic waves. The system detects incoming electromagnetic waves based on the electrons emitted from the electron emitter. According to a system having the above structure, for example, electromagnetic waves in the wavelength region between so-called millimeter waves and infrared light can be detected.

[0004] It is believed that the detection of electromagnetic waves in the wavelength region between millimeter waves and infrared light can be used for various applications. For example, if the wavelength components of electromagnetic waves that are transmitted through and absorbed by a gas are identified, then the gas components can be identified based on these identified wavelength components. The wavelength components corresponding to various gas components are contained within the wavelength region between millimeter waves and infrared light. Therefore, this wavelength region is also known as the molecular fingerprint region. If the entire aforementioned wavelength region can be detected, then a variety of gases can be easily detected.

[0005] As described above, to accommodate various applications, it is possible to expand the wavelength range of electromagnetic waves detectable in an electromagnetic wave detection device. In the example above, it is possible to expand the wavelength range of electromagnetic waves detectable in the electromagnetic wave detection device to cover the wavelength range corresponding to each of the various gas components. To further expand the wavelength range of electromagnetic waves detectable in an electromagnetic wave detection device, it is possible to expand the wavelength range of electromagnetic waves that can be converted into electrons in a photoelectric conversion device.

[0006] One aspect of the present invention aims to provide a photoelectric conversion device capable of expanding the wavelength range of electromagnetic waves that can be converted into electrons. Another aspect of the present invention aims to provide a photoelectric conversion method capable of expanding the wavelength range of electromagnetic waves that can be converted into electrons.

[0007] According to one aspect of the present invention, a photoelectric conversion device includes an electron emitter comprising a metasurface that emits electrons in response to the incidence of an electromagnetic wave. The metasurface includes a plurality of photoelectric conversion units sensitive to electromagnetic waves having mutually different wavelength regions. Each of the plurality of photoelectric conversion units comprises a pattern having a mutually different configuration.

[0008] In a photoelectric conversion device, the electron emitter includes a metasurface that emits electrons in response to the incidence of electromagnetic waves. The metasurface includes multiple photoelectric conversion units that are sensitive to electromagnetic waves having mutually different wavelength regions. Each of the multiple photoelectric conversion units includes a pattern having a mutually different configuration. As a result, the photoelectric conversion device, among the multiple photoelectric conversion units, is sensitive to electromagnetic waves having mutually different wavelength regions. Therefore, in the photoelectric conversion device, the wavelength range of electromagnetic waves that can be converted into electrons is expanded.

[0009] In the above aspects, the pattern of each photoelectric conversion unit may include first and second portions spaced apart from each other. The second portion may include a front end facing the first portion. The second portion may be configured to emit electrons in response to the incidence of electromagnetic waves when a potential lower than that of the first portion is applied to the second portion. In this case, the wavelength range of the electromagnetic waves that cause electrons to be emitted from the photoelectric conversion device can be controlled by controlling the application of potentials to the first and second portions.

[0010] In the above aspects, the second part of each photoelectric conversion unit may include a linear portion extending toward the first part. The linear portions of at least two of the plurality of photoelectric conversion units may have different lengths. Depending on the length of the linear portion, the wavelength range of the electromagnetic waves that cause electron emission in each photoelectric conversion unit is changed. Therefore, a simple configuration can be used to expand the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device.

[0011] In the aforementioned aspects, in two of a plurality of photoelectric conversion units, the first or second portion of one photoelectric conversion unit can be electrically connected to the first or second portion of the other photoelectric conversion unit. In this case, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device can be expanded through a simple configuration.

[0012] In the aforementioned aspects, the photoelectric conversion device may further include a potential control unit configured to control the potential applied to the first and second portions of each photoelectric conversion unit. In this case, the photoelectric conversion unit to be operated can be selected by the potential control unit.

[0013] In the above aspects, the plurality of photoelectric conversion units may include: a first photoelectric conversion unit and a second photoelectric conversion unit. The potential control unit may be configured to control the potentials applied to the first and second portions of the first photoelectric conversion unit, and the first and second portions of the second photoelectric conversion unit. The potential difference between the potential applied to the first portion of the first photoelectric conversion unit and the potential applied to the second portion of the first photoelectric conversion unit, and the potential difference between the potential applied to the first portion of the second photoelectric conversion unit and the potential applied to the second portion of the second photoelectric conversion unit, may be different from each other. In this case, the first photoelectric conversion unit and the second photoelectric conversion unit operate separately. Therefore, the photoelectric conversion device can change the wavelength range of electromagnetic waves that can be converted into electrons.

[0014] In the above-described aspect, when a potential lower than that applied to the first part of the second photoelectric conversion unit is applied to the second part of the second photoelectric conversion unit, the potential control unit can be configured to apply a potential higher than that applied to the first part of the first photoelectric conversion unit to the second part of the first photoelectric conversion unit. In this case, the emission of electrons in response to the incident electromagnetic wave from the first photoelectric conversion unit can be safely stopped, while electrons can be emitted from the second photoelectric conversion unit in response to the incident electromagnetic wave.

[0015] In the above aspects, for at least two photoelectric conversion units, the potential control unit can be configured to apply a potential lower than that applied to the first part to the second part. In this case, the at least two photoelectric conversion units operate simultaneously. Therefore, the conversion of electromagnetic waves in wavelength regions corresponding to the plurality of photoelectric conversion units into electrons can be performed simultaneously.

[0016] In the above aspects, the patterns of each photoelectric conversion unit can be of the same potential. In this case, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device can be expanded through simple configuration.

[0017] In the above aspects, the patterns of each photoelectric conversion unit can be electrically connected to each other. In this case, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device can be expanded through a simpler configuration.

[0018] In the above aspects, the pattern of each photoelectric conversion unit may include linear portions. The linear portions of at least two of the plurality of photoelectric conversion units may have different lengths. Depending on the length of the linear portions, the wavelength range of the electromagnetic waves that cause electron emission in each photoelectric conversion unit is changed. As a result, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device can be expanded through simple configuration.

[0019] In addition to the above aspects, a housing configured to be hermetically sealed and having a window that transmits electromagnetic waves may also be provided. An electron transmitter may be disposed within the housing. In this case, the amount of electrons emitted in response to the incident electromagnetic waves can be increased by evacuating the housing or filling the housing with gas.

[0020] According to another aspect of the present invention, a photoelectric conversion method includes: introducing an electromagnetic wave to be measured into a metasurface comprising a plurality of photoelectric conversion units, and emitting electrons from at least one photoelectric conversion unit corresponding to a wavelength region of the electromagnetic wave to be measured. The plurality of photoelectric conversion units each comprise patterns having mutually different configurations.

[0021] In a photoelectric conversion method, the electromagnetic wave to be measured enters a metasurface comprising multiple photoelectric conversion units. Each photoelectric conversion unit comprises a pattern with a different configuration. Electrons are emitted from at least one photoelectric conversion unit corresponding to the wavelength region of the electromagnetic wave to be measured. In this case, the wavelength range of the electromagnetic wave that can be converted into electrons is expanded.

[0022] In another aspect described above, the photoelectric conversion method may further include controlling a potential applied to a plurality of photoelectric conversion units. The pattern of each photoelectric conversion unit may include: a first portion and a second portion spaced apart from the first portion and having a front end facing the first portion. With a potential lower than that applied to the first portion applied to the second portion, each photoelectric conversion unit may emit electrons in response to the incidence of an electromagnetic wave. The potentials applied to the first and second portions of each photoelectric conversion unit may be controlled. In this case, the photoelectric conversion unit to be operated is selected by controlling the potentials applied to the first and second portions of each photoelectric conversion unit.

[0023] In another aspect described above, the potential applied to the first and second photoelectric conversion units included in the plurality of photoelectric conversion units can be controlled. Alternatively, the potential can be applied in a manner different from the potential difference between the potential applied to the first portion and the potential applied to the second portion of the first photoelectric conversion unit, and the potential difference between the potential applied to the first portion and the potential applied to the second portion of the second photoelectric conversion unit. In this case, since the potentials applied to the first and second photoelectric conversion units are controlled separately, the first and second photoelectric conversion units can be operated separately.

[0024] In another aspect described above, when a potential lower than that applied to the first part of the second photoelectric conversion unit is applied to the second part of the second photoelectric conversion unit, a potential higher than that applied to the first part of the first photoelectric conversion unit can be applied to the second part of the first photoelectric conversion unit. Conversely, when a potential lower than that applied to the first part of the first photoelectric conversion unit is applied to the second part of the first photoelectric conversion unit, a potential higher than that applied to the first part of the second photoelectric conversion unit can be applied to the second part of the second photoelectric conversion unit. In this case, when one of the first and second photoelectric conversion units emits electrons in response to the incident electromagnetic wave, the emission of electrons in response to the incident electromagnetic wave from the other can be safely stopped.

[0025] In another aspect described above, in at least two of the plurality of photoelectric conversion units, a potential lower than that applied to the first part can be applied to the second part. In this case, the plurality of photoelectric conversion units operate simultaneously. Therefore, the conversion of electromagnetic waves having wavelengths respectively corresponding to the plurality of photoelectric conversion units can be performed simultaneously.

[0026] According to one aspect of the present invention, a photoelectric conversion device capable of expanding the wavelength range of electromagnetic waves that can be converted into electrons can be provided. According to another aspect of the present invention, a photoelectric conversion method capable of expanding the wavelength range of electromagnetic waves that can be converted into electrons can be provided. Attached Figure Description

[0027] Figure 1 This is a perspective view of the electromagnetic wave detection device according to the first embodiment;

[0028] Figure 2 This is a schematic diagram of the photoelectric conversion device according to the first and second embodiments;

[0029] Figure 3 This is a top view of the electron transmitter according to the first embodiment;

[0030] Figure 4 This is a schematic diagram of the photoelectric conversion device according to the first embodiment;

[0031] Figure 5 This is a flowchart of the electromagnetic wave detection method according to the first embodiment;

[0032] Figure 6 This is a flowchart of an electromagnetic wave detection method according to a variation of the first embodiment;

[0033] Figure 7 This is a top view of the electron transmitter according to the second embodiment;

[0034] Figure 8This is a top view of an electron transmitter according to a modified example of the second embodiment;

[0035] Figure 9 This is a top view of an electron transmitter according to a modified example of the second embodiment;

[0036] Figure 10 This is a perspective view of the electromagnetic wave detection device according to the third embodiment;

[0037] Figure 11A A top view of an electron transmitter according to a third embodiment; and

[0038] Figure 11B This is a top view of an electron transmitter according to a variation of the third embodiment. Detailed Implementation

[0039] The first and second embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and redundant explanations are omitted.

[0040] [First Implementation Method]

[0041] First, refer to Figure 1 The configuration of the electromagnetic wave detection device according to the first embodiment is described. Figure 1 This is a perspective view of the electromagnetic wave detection device according to the first embodiment.

[0042] Electromagnetic wave detection device 1 detects incoming electromagnetic waves. Electromagnetic wave detection device 1 includes a photoelectric conversion device 2. The photoelectric conversion device 2 emits electrons in response to the incident electromagnetic wave. In this specification, the term "light" includes electromagnetic waves other than visible light. In this embodiment, electromagnetic wave detection device 1 detects incoming electromagnetic waves based on electrons emitted from the photoelectric conversion device 2 in response to the incident electromagnetic wave. The photoelectric conversion device 2 emits electrons, for example, in response to the incident electromagnetic wave having a wavelength range between so-called millimeter waves and infrared light. The wavelength range between millimeter waves and infrared light corresponds, for example, a frequency range between about 0.01 and 150 THz. In this specification, the term "wavelength range" can include a range of multiple wavelength regions separated from each other, or it can be a range of a continuous wavelength region. The photoelectric conversion device 2 emits electrons, for example, based on electron field emission (field emission).

[0043] The electromagnetic wave detection device 1 is, for example, an electron tube that outputs an electrical signal in response to the incidence of an electromagnetic wave. For example, inside the electron tube, the electromagnetic wave detection device 1 emits electrons in response to the incidence of an electromagnetic wave, detects the emitted electrons, and outputs an electrical signal based on the detection result. The electron tube is, for example, a photomultiplier tube (PMT). When an electromagnetic wave enters, the electromagnetic wave detection device 1 emits electrons internally and multiplies the emitted electrons. According to a variation of this embodiment, the electromagnetic wave detection device 1 may not be configured within the electron tube for detecting electrons. In other words, the electromagnetic wave detection device 1 may include an electron tube that emits electrons to the outside in response to the incidence of an electromagnetic wave as a photoelectric conversion device 2, and may include a sensor outside the electron tube that detects the electrons emitted from the electron tube.

[0044] The electromagnetic wave detection device 1 includes a housing 10, an electron transmitter 20, a holder 30, an electron multiplier unit 40, an electron collecting unit 50, and a power supply unit 60. The electron transmitter 20, holder 30, electron multiplier unit 40, and electron collecting unit 50 are disposed within the housing 10. The photoelectric conversion device 2 includes the housing 10, electron transmitter 20, and power supply unit 60, and constitutes part of the electromagnetic wave detection device 1.

[0045] The housing 10 has a valve 11 and a stem 12. The interior of the housing 10 is hermetically sealed by the valve 11 and the stem 12. In this embodiment, the interior of the housing 10 is maintained as a vacuum. The vacuum in the housing 10 does not have to be an absolute vacuum, but can be a state in which the housing is filled with a gas at a pressure lower than atmospheric pressure. For example, the interior of the housing 10 is maintained at 1×10⁻⁶. -4 Up to 1×10 -7 Pa.

[0046] Valve 11 includes a window unit 11a with electromagnetic wave transparency. In this specification, the term "electromagnetic wave transparency" refers to the characteristic of transmitting at least a portion of the frequency wavelength range of an incoming electromagnetic wave. In this embodiment, the housing 10 has a cylindrical shape. Figure 1 As shown, housing 10 extends in the X-axis direction. Rod 12 forms the bottom surface of housing 10. Rod 12 also forms, for example, an end face of housing 10 in the X-axis direction. Valve 11 forms the side surface of housing 10 and the bottom surface facing rod 12.

[0047] Window unit 11a forms the bottom surface facing rod 12. For example, when viewed from the X-axis direction, window unit 11a is formed in a circular shape, and the YZ axis direction is set as the diameter direction. The frequency characteristics of electromagnetic wave transmittance vary depending on the material. Therefore, window unit 11a is made of a suitable material according to the frequency range of electromagnetic waves entering housing 10. For example, the material of window unit 11a includes at least one of quartz, silicon, germanium, sapphire, zinc selenide, zinc sulfide, magnesium fluoride, lithium fluoride, barium fluoride, calcium fluoride, magnesium oxide, calcium carbonate, diamond, and chalcogenide glass. Therefore, electromagnetic waves with any frequency range between millimeter waves and infrared light can be guided into the interior of housing 10. For example, quartz is suitable for components that transmit electromagnetic waves in the frequency range of 0.1 to 5 THz; silicon is suitable for components that transmit electromagnetic waves in the frequency range of 0.04 to 11 THz and above 46 THz; magnesium fluoride is suitable for components that transmit electromagnetic waves in the frequency range of 40 THz and above; germanium is suitable for components that transmit electromagnetic waves in the frequency range of 13 THz and above; and zinc selenide is suitable for components that transmit electromagnetic waves in the frequency range of 14 THz and above.

[0048] The housing 10 also has multiple wires 13 for electrically connecting the exterior and interior of the housing 10. The multiple wires 13 are, for example, leads or pins. In this embodiment, the multiple wires 13 are pins passing through the rod 12 and extending from the interior of the housing 10 to its exterior. At least one of the multiple wires 13 is connected to various components disposed inside the housing 10.

[0049] Electron emitter 20 emits electrons in response to the incidence of electromagnetic waves. Electron emitter 20 is provided with a support body 21. The support body 21 has, for example, a plate-like shape. In a top view, the support body 21 is, for example, rectangular. The support body 21 has two opposing main surfaces 21a and 21b. Main surfaces 21a and 21b are surfaces of the support body 21 located on opposite sides. Main surfaces 21a and 21b are, for example, flat surfaces and are rectangular in shape in a top view. Main surfaces 21a and 21b are configured parallel to window unit 11a. Main surface 21a faces window unit 11a. Electromagnetic waves passing through window unit 11a enter main surface 21a.

[0050] The support 21 is electromagnetically transparent to electromagnetic waves passing through the window unit 11a. As a result, the support 21 transmits at least a portion of the frequency range of electromagnetic waves passing through the window unit 11a. The support 21 may be made of the same material as the window unit 11a. For example, the material of the support 21 includes silicon. In a photoelectric conversion device 2, the support 21 and the window unit 11a may not be made of the same material. The support 21 is separated from the window unit 11a and the electron multiplication unit 40.

[0051] Electron emitter 20 has a metasurface 22. The metasurface 22 is disposed on a support 21. The metasurface 22 emits electrons in response to the incidence of electromagnetic waves. For example, the metasurface 22 is sensitive to electromagnetic waves in the wavelength range between so-called millimeter waves and infrared light. The metasurface 22 is also sensitive to terahertz waves. The wavelength range of terahertz waves corresponds to the frequency range between 100 GHz and 30 THz. The term "sensitive to electromagnetic waves" means emitting electrons in response to the incidence of electromagnetic waves.

[0052] For example, metasurface 22 includes an oxide layer formed on the main surface 21b of the support 21 and a metal layer formed on the oxide layer. The oxide layer is made of materials such as silicon dioxide and titanium dioxide. For example, the oxide layer includes a silicon dioxide-containing layer and a titanium dioxide-containing layer. The metal layer is made of materials such as gold. In this embodiment, the oxide layer is formed on the main surface 21b of the support 21, which is made of quartz, and the metal layer is formed on the oxide layer. For example, the thickness of the support 21 is 525 μm, the thickness of the layer including the silicon diode in the metasurface 22 is 1 μm, the thickness of the layer including the titanium dioxide in the metasurface 22 is 10 nm, and the thickness of the metal layer in the metasurface 22 is 200 nm. The metasurface 22 has a rectangular shape in a top view. In a variation of this embodiment, the metasurface 22 may be disposed on the main surface 21a.

[0053] The retainer 30 holds the electron emitter 20 inside the housing 10. The retainer 30 is positioned on the inner surface 10a of the housing 10. The retainer 30 positions the electron emitter 20 against the housing 10. The retainer 30 has a frame shape along the inner surface 10a of the housing 10 and a through opening is formed in the retainer 30. Viewed from a direction orthogonal to the main surfaces 21a and 21b of the electron emitter 20, the metasurface 22 of the electron emitter 20 is disposed inside the edge defining the through opening.

[0054] An electron multiplier unit 40 is disposed inside the housing 10 and has an incident surface 40a into which electrons emitted from the electron emitter 20 enter. The electron multiplier unit 40 multiplies the electrons entering the incident surface 40a. In this embodiment, the main surface 21b of the electron emitter 20 faces the incident surface 40a of the electron multiplier unit 40. A metasurface 22 faces the incident surface 40a of the electron multiplier unit 40, and electrons emitted from the metasurface 22 enter the incident surface 40a. The main surface 21a of the electron emitter 20 faces the window unit 11a of the housing 10. The electron multiplier unit 40 has, for example, multi-stage multiplication electrodes.

[0055] An electron collection unit 50 is disposed inside the housing 10 and collects electrons multiplied by the electron multiplier unit 40. The electron collection unit 50 is a sensor for detecting electrons. The electromagnetic wave detection device 1 detects electromagnetic waves by detecting electrons in the electron collection unit 50. In this embodiment, for example, the electron collection unit 50 has an anode connected to one of a plurality of wires 13. A predetermined potential is applied to the anode through the wires 13. The anode captures electrons multiplied by the multiplication electrode of the electron multiplier unit 40. The electron collection unit 50 may have a diode instead of an anode.

[0056] In this embodiment, the metasurface 22 is an active type and operates by applying a bias voltage. The metasurface 22 operates by applying a potential via a power supply unit 60. The power supply unit 60 is electrically connected to the metasurface 22. The power supply unit 60 includes a potential application unit 61 and a potential control unit 62. The potential application unit 61 applies a potential to the metasurface 22. The potential control unit 62 controls the potential application unit 61. The potential applied to the metasurface 22 is controlled by the potential control unit 62. The metasurface 22 operates in response to the potential controlled by the potential control unit 62. In other words, the metasurface 22 emits electrons in response to the potential control of the potential control unit 62.

[0057] The potential control unit 62 is, for example, one or more computers comprised of hardware and software such as programs. The potential control unit 62 includes, for example, a processor, main memory, auxiliary memory, communication devices, and input devices as hardware. The processor executes the operating system and application programs. The main memory consists of read-only memory (ROM) and random access memory (RAM). The auxiliary memory is a storage medium consisting of hard disks and flash memory. The auxiliary memory typically stores more data than the main memory. The communication devices consist of a network interface card (NIC) or a wireless communication module. The input devices consist of a keyboard, a mouse, and a touch panel.

[0058] [Configuration of photoelectric conversion device]

[0059] Next, refer to Figures 2 to 4 The photoelectric conversion device 2 will be described in further detail. Figure 2 This is a schematic diagram of a photoelectric conversion device. Metasurface 22 includes multiple photoelectric conversion units 23, 24, and 25. Each photoelectric conversion unit 23, 24, and 25 emits electrons in response to incident light of a corresponding wavelength. The multiple photoelectric conversion units 23, 24, and 25 emit electrons in response to incident electromagnetic waves having mutually different wavelength regions. In other words, the multiple photoelectric conversion units 23, 24, and 25 are sensitive to electromagnetic waves having mutually different wavelength regions. The term "mutually different wavelength regions" includes cases where multiple wavelength regions overlap and cases where multiple wavelength regions are separated from each other.

[0060] Metasurface 22 includes, for example, three photoelectric conversion units 23, 24, and 25. Metasurface 22 may include two, four, or more photoelectric conversion units corresponding to electromagnetic waves having mutually different wavelength regions. Metasurface 22 may also include multiple photoelectric conversion units corresponding to electromagnetic waves having the same wavelength region. In other words, metasurface 22 may be sensitive to electromagnetic waves having the same wavelength region. For example, photoelectric conversion units 23 and 24 may correspond to electromagnetic waves having the same wavelength region, and photoelectric conversion unit 25 may correspond to electromagnetic waves having a different wavelength region than photoelectric conversion units 23 and 24.

[0061] For example, photoelectric conversion unit 23 is sensitive to a frequency range centered at 0.5 THz, photoelectric conversion unit 24 is sensitive to a frequency range centered at 1.0 THz, and photoelectric conversion unit 25 is sensitive to a frequency range centered at 1.5 THz. The frequency ranges to which photoelectric conversion units 23, 24, and 25 are sensitive are not limited to these. For example, photoelectric conversion unit 23 may be sensitive to a frequency range centered at 0.5 THz, photoelectric conversion unit 24 may be sensitive to a frequency range centered at 10 THz, and photoelectric conversion unit 25 may be sensitive to a frequency range centered at 100 THz.

[0062] exist Figure 2 In the illustrated example, electromagnetic waves W entering the housing 10 enter photoelectric conversion units 23, 24, and 25. In this case, the photoelectric conversion units 23, 24, and 25 corresponding to the wavelength of electromagnetic wave W emit electrons E in response to the incident electromagnetic wave W. Electrons E emitted from at least one of the photoelectric conversion units 23, 24, and 25 enter the electron multiplication unit 40. The electrons multiplied in the electron multiplication unit 40 are collected in the electron collection unit 50.

[0063] Figure 3 This is a top view of the electron transmitter. (Example) Figure 3 As shown, the plurality of photoelectric conversion units 23, 24, and 25 in the metasurface 22 each include patterns with mutually different configurations. The term "configuration" includes various properties such as shape and material. Each pattern is configured on the main surface 21b of the support 21. In this embodiment, each pattern has mutually different shapes. The term "having mutually different shapes" includes having mutually different dimensions.

[0064] In this embodiment, each photoelectric conversion unit 23, 24, and 25 includes patterns 33, 34, and 35 having mutually different shapes. Photoelectric conversion unit 23 includes pattern 33, photoelectric conversion unit 24 includes pattern 34, and photoelectric conversion unit 25 includes pattern 35. Each pattern 33, 34, and 35 is a conductive line and conducts electrons. Each pattern 33, 34, and 35 includes at least a metal layer formed on the oxide layer of the metasurface 22. The material of the metal layer includes, for example, gold.

[0065] Each pattern 33, 34, and 35 includes a first portion 37 and a second portion 38. The first portion 37 and the second portion 38 are spaced apart from each other. The second portion 38 extends toward the first portion 37. The second portion 38 includes a front end 39 facing the first portion 37. In each pattern 33, 34, and 35, the first portion 37 and the second portion 38 are connected via an oxide layer. In each pattern 33, 34, and 35, the first portion 37 and the second portion 38 are separated by an oxide layer and are insulated from each other, at least when the photoelectric conversion device 2 is not in operation. The second portion 38 emits electrons in response to the incidence of electromagnetic waves when a potential lower than that of the first portion 37 is applied.

[0066] exist Figure 3 In the illustrated examples, the first portion 37 of each pattern 33, 34, and 35 includes a pair of linear parts 41 extending in the Y-axis direction. Each linear part 41 is formed, for example, in a straight line shape. The pair of linear parts 41 are parallel to each other. The second portion 38 of each pattern 33, 34, and 35 includes: a plurality of linear parts 42 extending in the Z-axis direction, and a linear part 43 extending in the Y-axis direction and connecting the plurality of linear parts 42.

[0067] In patterns 33, 34, and 35, a plurality of linear portions 42 are arranged between a pair of linear portions 41. The plurality of linear portions 42 extend from linear portions 43 toward corresponding first portions 37. Each linear portion 42 is, for example, formed in a straight line shape. The plurality of linear portions 42 are, for example, parallel to each other. The linear portions 43 are, for example, formed in a straight line shape. The pair of linear portions 41 are, for example, parallel to the linear portions 43. Each linear portion 42 is connected to the linear portion 43 at its center. In other words, each linear portion 42 extends from the linear portion 43 in both the +Z-axis and -Z-axis directions.

[0068] exist Figure 3In the illustrated example, each linear portion 42 includes a pair of front ends 39. Each front end 39 is spaced apart from other linear portions 42 and 43 in the same pattern, and also spaced apart from other patterns. In patterns 33, 34, and 35, each front end 39 faces a different linear portion 41 in the Z-axis direction. The shortest distance between each front end 39 and the first portion 37 is less than the shortest distance between the second portion 38 (excluding the multiple front ends 39) and the first portion 37. In other words, the front end 39 is the portion of the linear portion 41 in the linear portion 42 that includes the front end 39 that is closest to the corresponding first portion 37. The front end 39 is configured to be closer to the linear portion 41 than other portions of the pattern that includes the front end 39.

[0069] In each photoelectric conversion unit 23, 24, and 25, the linear portion 41 constitutes a bias portion, and the linear portion 42 constitutes an antenna portion. The antenna portion emits electrons in response to the incident electromagnetic wave. When a bias potential is applied, an electric field is generated between the bias portion and the corresponding antenna portion. When a potential higher than the potential of the antenna portion is applied to the bias portion, the electric potential barrier in the front end portion of the antenna portion on the bias portion side becomes thinner. When a potential lower than the potential of the antenna portion is applied to the bias portion, the electric potential barrier in the front end portion of the antenna portion on the bias portion side becomes thicker. The state in which a potential higher than the potential of the antenna portion is applied to the bias portion is called "forward bias." The state in which a potential lower than the potential of the antenna portion is applied to the bias portion is called "reverse bias."

[0070] When an electromagnetic wave enters the antenna section, an electric field is induced around it. The potential barrier at the antenna-vacuum interface thins due to the induced electric field around the antenna section. As the potential barrier thins further due to the electromagnetic wave incident on the antenna section under a forward bias state, electrons present in the antenna section slip out of the barrier due to the tunneling effect. These slipped electrons are accelerated by the electric field around the antenna section. As described above, under a forward bias state, the incident electromagnetic wave on the antenna section can generate the emission of electric field electrons. In each photoelectric conversion unit 23, 24, and 25, when a potential lower than that of the linear portion 41 of the first portion 37 is applied, the linear portion 42 of the second portion 38 can emit electrons in response to the incident electromagnetic wave.

[0071] The smaller the size of the antenna section, the more electric field electrons are emitted for electromagnetic waves with shorter wavelengths (i.e., electromagnetic waves with higher frequencies). According to the change in the configuration of the linear section 42 of the second part 38, the photoelectric conversion units 23, 24 and 25 of the metasurface 22 are configured to correspond to, for example, the wavelength range between millimeter waves and infrared light.

[0072] At least two of the photoelectric conversion units 23, 24, and 25 have linear portions 42 of different lengths. For example, the linear portions 42 of the multiple patterns 33, 34, and 35 have different lengths T1, T2, and T3. In other words, the linear portions 42 of photoelectric conversion unit 23, photoelectric conversion unit 24, and photoelectric conversion unit 25 have different lengths T1, T2, and T3. The lengths T1, T2, and T3 of the linear portions 42 in patterns 33, 34, and 35 are the lengths from one end point 39 to another end point 39 of the linear portion 42 in the Z-axis direction.

[0073] In pattern 33, the lengths T1 of the multiple linear portions 42 are the same. In pattern 34, the lengths T2 of the multiple linear portions 42 are the same. In pattern 35, the lengths T3 of the multiple linear portions 42 are the same. The term "same" includes differences in length within manufacturing tolerances. The lengths T1, T2, and T3 of the linear portions 42 in each of patterns 33, 34, and 35 correspond to the wavelength regions of electromagnetic waves that cause electrons to be emitted from each of the photoelectric conversion units 23, 24, and 25. The lengths T1, T2, and T3 of the linear portions 42 in each of patterns 33, 34, and 35 are designed according to the wavelength regions required for the emission of electrons from each of the photoelectric conversion units 23, 24, and 25. For example, each length T1, T2, and T3 is half the length of the center wavelength in the required wavelength region. In the case where electromagnetic waves pass through the support 21 and enter the linear portion 42 as in this embodiment, the refractive index of the support 21 through which the electromagnetic waves pass is also considered. For example, if the wavelength of the electromagnetic wave entering the electron tube is 600 μm and the refractive index of the support 21 for electromagnetic waves is 3.4, the wavelength of the electromagnetic wave entering the linear portion 42 is 600 μm / 3.4 = 176 μm. Therefore, in this case, lengths T1, T2, and T3 of 176 μm / 2 = 88 μm are appropriate.

[0074] like Figure 3 As explained, the electron emitter 20 is further provided with a plurality of electrodes 51, 52, 53, and 54 spaced apart from each other. The plurality of electrodes 51, 52, 53, and 54 are disposed on the main surface 21b of the support 21. The plurality of electrodes 51, 52, 53, and 54 are electrically connected to at least one of the plurality of photoelectric conversion units 23, 24, and 25. In this embodiment, each electrode 51, 52, 53, and 54 is formed in a rectangular shape. As a variation of this embodiment, each electrode 51, 52, 53, and 54 may be formed in a straight line shape in the same manner as the first portion 37 or the second portion 38. Each electrode 51, 52, 53, and 54 may be integrally formed with the first portion 37 or the second portion 38.

[0075] For example, electrode 51 is electrically connected to the second portion 38 of each photoelectric conversion unit 23, 24, and 25. Electrode 52 is electrically connected to a pair of first portions 37 of photoelectric conversion unit 23. Electrode 53 is electrically connected to a pair of first portions 37 of photoelectric conversion unit 24. Electrode 54 is electrically connected to a pair of first portions 37 of photoelectric conversion unit 25.

[0076] In two of the multiple photoelectric conversion units 23, 24, and 25, a first portion 37 or a second portion 38 of one photoelectric conversion unit may be electrically connected to a first portion 37 or a second portion 38 of the other photoelectric conversion unit. For example, in Figure 3 In the illustrated example, the second portion 38 of photoelectric conversion unit 23, the second portion 38 of photoelectric conversion unit 24, and the second portion 38 of photoelectric conversion unit 25 are electrically connected via electrode 51.

[0077] Each photoelectric conversion unit 23, 24, and 25 is operated by applying a potential from the power supply unit 60 via multiple electrodes 51, 52, 53, and 54. The potential application unit 61 of the power supply unit 60 applies a potential to each photoelectric conversion unit 23, 24, and 25 via the multiple electrodes 51, 52, 53, and 54. The potential control unit 62 of the power supply unit 60 controls the potential applied to each photoelectric conversion unit 23, 24, and 25.

[0078] Figure 4 This is a schematic diagram used to illustrate the application of an electric potential in a photoelectric conversion device. For example... Figure 4 As shown, the potential application unit 61 includes, for example, a first potential application unit 61a, a second potential application unit 61b, and a third potential application unit 61c. The first potential application unit 61a applies a potential difference between electrodes 51 and 52. The second potential application unit 61b applies a potential difference between electrodes 51 and 53. The third potential application unit 61c applies a potential difference between electrodes 51 and 54. The potential control unit 62 controls the first potential application unit 61a, the second potential application unit 61b, and the third potential application unit 61c, respectively.

[0079] [Photoelectric Conversion Method]

[0080] Next, refer to Figure 5 This describes an electromagnetic wave detection method according to this embodiment. The electromagnetic wave detection method includes a photoelectric conversion method that emits electrons in response to an incident electromagnetic wave. Figure 5 This is a flowchart of the electromagnetic wave detection method according to this embodiment. Figure 5 In the electromagnetic wave detection method shown, the wavelength range to be detected is determined. This wavelength range is divided into multiple wavelength regions, and detection is performed on each wavelength region. As a result, for the determined wavelength range, the same results as those obtained from spectroscopy can be obtained. Figure 5 In the example shown, multiple photoelectric conversion units are operated sequentially to detect the wavelength regions corresponding to the photoelectric conversion units.

[0081] First, prepare the electron transmitter 20 (process S1). For example, configure the electromagnetic wave detection device 1 with the electron transmitter 20.

[0082] Next, the wavelength range is determined (process S2). For example, the potential control unit 62 acquires various information from an external source and determines the wavelength range of the electromagnetic wave to be detected based on this information. This information can be input by the user or acquired automatically via communication. The potential control unit 62 can determine the wavelength range of the electromagnetic wave to be detected based on various pre-stored information.

[0083] Next, the photoelectric conversion unit to be operated is determined (process S3). The potential control unit 62 determines the photoelectric conversion unit to be operated, for example, based on the wavelength range determined in process S2. The potential control unit 62 determines at least one photoelectric conversion unit that is sensitive to the wavelength range determined in process S2 as the photoelectric conversion unit to be operated. For example, the potential control unit 62 determines photoelectric conversion unit 23 of the plurality of photoelectric conversion units 23, 24 and 25 as an operating electron change unit, and determines photoelectric conversion units 24 and 25 as non-operating photoelectric conversion units.

[0084] Next, a potential is applied to the photoelectric conversion unit (process S4). The potential control unit 62 determines, for example, the potential applied to each of the electrodes 51, 52, 53, and 54 based on the operating photoelectric conversion unit. For example, the potential control unit 62 refers to a pre-stored table and obtains information associated with the operating photoelectric conversion unit. The potential control unit 62 determines the potential applied to each of the electrodes 51, 52, 53, and 54 based on the obtained information.

[0085] For example, the potential control unit 62 controls the bias voltage applied to the operating and non-operating photoelectric conversion units among the plurality of photoelectric conversion units. For example, the potential difference between the potential applied to the first portion 37 and the potential applied to the second portion 38 of the operating photoelectric conversion unit is different from the potential difference between the potential applied to the first portion 37 and the potential applied to the second portion 38 of the non-operating photoelectric conversion unit.

[0086] The potential control unit 62 determines the potential applied to each photoelectric conversion unit, for example, by applying a forward bias voltage to the operating photoelectric conversion unit and a reverse bias voltage to the non-operating photoelectric conversion unit. The potential control unit 62 controls the potential application unit 61 and applies the determined potential to each photoelectric conversion unit. In other words, in the operating photoelectric conversion unit, the potential control unit 62 applies a potential higher than the potential applied to the first part 37 to the second part 38. In the non-operating photoelectric conversion unit, the potential control unit 62 applies a potential lower than the potential applied to the first part 37 to the second part 38.

[0087] For example, when a potential lower than that applied to the first portion 37 of photoelectric conversion unit 24 is applied to the second portion 38 of photoelectric conversion unit 24, the potential control unit 62 applies a potential higher than that applied to the first portions of photoelectric conversion units 23 and 25 to the second portions. In this case, photoelectric conversion unit 24 is operated, while photoelectric conversion units 23 and 25 are not operated. Therefore, electrons are emitted from the metasurface 22 only when electromagnetic waves in the wavelength region corresponding to photoelectric conversion unit 24 enter the photoelectric conversion device 2.

[0088] Next, the electromagnetic wave enters the metasurface 22 (process S5). For example, the electromagnetic wave passing through the window unit 11a of the housing 10 enters the metasurface 22. For example, the electromagnetic wave to be measured enters the metasurface 22. Therefore, electrons are emitted from at least one of the plurality of photoelectric conversion units 23, 24 and 25 corresponding to the wavelength region of the electromagnetic wave to be measured. The window unit 11a is configured to transmit the electromagnetic wave to be measured.

[0089] Next, electromagnetic waves are detected in response to electrons emitted from metasurface 22 (process S6). The electromagnetic wave detection device 1 detects electromagnetic waves while applying the potential determined in process S4 to each photoelectric conversion unit. For example, the electromagnetic wave detection device 1 multiplies electrons emitted from electron emitter 20 and detects the multiplied electrons. Therefore, the electromagnetic wave detection device 1 detects electromagnetic waves entering from the window unit 11a of the housing 10.

[0090] Next, it is determined whether the electromagnetic wave detection process is complete under the current operating state (process S7). In other words, it is determined whether the electromagnetic wave detection process is complete under the operating state of the photoelectric conversion unit determined in process S3. If it is determined that the detection process is not complete, the process proceeds to process S5. If it is determined that the detection process is complete, the process proceeds to process S8. The determination in process S7 can be performed, for example, by the potential control unit 62, or by other control units in the electromagnetic wave detection device 1.

[0091] Next, it is determined whether all detections within the wavelength range determined in process S2 have been completed (process S8). For example, it is determined whether the potential control unit 62 has operated all photoelectric conversion units sensitive to the wavelength range determined in process S2. If it is determined that all photoelectric conversion units sensitive to the wavelength range determined in process S2 have been operated, it is determined that the detection of the wavelength range determined in process S2 has been completed. The determination in process S8 can be performed by other control units in the electromagnetic wave detection device 1.

[0092] If all detections within the wavelength range determined in process S8 are not completed, the process proceeds to process S9. In this case, the photoelectric conversion unit to be operated is changed (process S9). For example, the potential control unit 62 changes the photoelectric conversion unit to be operated based on the wavelength range determined in process S3. For example, the potential control unit 62 determines the unoperated photoelectric conversion unit among the photoelectric conversion units that are sensitive to the wavelength range determined in process S2 as the photoelectric conversion unit to be operated. When the photoelectric conversion unit to be operated is changed in process S9, the process proceeds to process S4.

[0093] For example, the potential control unit 62 switches the state from one where photoelectric conversion unit 24 is operating and photoelectric conversion units 23 and 25 are not operating to one where photoelectric conversion unit 25 is operating and photoelectric conversion units 23 and 24 are not operating. In this case, a potential lower than that applied to the first portion 37 of photoelectric conversion unit 25 is applied to the second portion 38 of photoelectric conversion unit 25, and a potential higher than that applied to the first portion 37 of photoelectric conversion units 23 and 24 is applied to the second portion 38 of photoelectric conversion units 23 and 24. Therefore, the state switches from one where electrons are emitted from the metasurface 22 when electromagnetic waves corresponding only to the wavelength region of photoelectric conversion unit 24 enter the photoelectric conversion device 2 to one where electrons are emitted from the metasurface 22 when electromagnetic waves corresponding only to the wavelength region of photoelectric conversion unit 25 enter the photoelectric conversion device 2.

[0094] Having confirmed in process S8 that detection across all wavelength ranges has been completed, the series of processes in the electromagnetic wave detection method is finished. As described above, in Figure 5 In the electromagnetic wave detection method shown, detection of each wavelength region within the wavelength range to be detected is performed by switching the photoelectric conversion unit to be operated and repeating processes S4 to S7. The order of the photoelectric conversion units to be operated can be determined in process S3.

[0095] In this embodiment, for example, when photoelectric conversion unit 23 is determined to be an operating photoelectric conversion unit and photoelectric conversion units 24 and 25 are determined to be non-operating photoelectric conversion units, in process S3, a forward bias potential is applied to photoelectric conversion unit 23, and a reverse bias potential is applied to photoelectric conversion units 24 and 25. Then, when photoelectric conversion unit 24 is determined to be an operating photoelectric conversion unit and photoelectric conversion units 23 and 25 are determined to be non-operating photoelectric conversion units, in process S9, a forward bias potential is applied to photoelectric conversion unit 24, and a reverse bias potential is applied to photoelectric conversion units 23 and 25.

[0096] Next, refer to Figure 6 This describes a photoelectric conversion method according to a variation of this embodiment. The main description is related to... Figure 5 The examples described differ from each other, and some repeated parts are omitted. Figure 6 This is a flowchart of the electromagnetic wave detection method according to this embodiment. Figure 6 In the electromagnetic wave detection method shown, a wavelength range to be detected is determined, and the presence of electromagnetic waves having wavelength components within the determined wavelength range is detected. The wavelength range to be detected can be multiple wavelength regions that are separate from each other. Figure 6 In the example shown, electromagnetic wave detection is performed while multiple photoelectric conversion units corresponding to a defined wavelength range are operating simultaneously. Figure 6 The electromagnetic wave detection method shown simultaneously detects electromagnetic waves with wavelength components in multiple wavelength regions.

[0097] First, prepare the electron transmitter 20 (process S11). For example, configure the electromagnetic wave detection device 1 with the electron transmitter 20.

[0098] Next, the wavelength range is determined (process S12). For example, the potential control unit 62 acquires various information from an external source and determines the wavelength range of the electromagnetic wave to be detected based on this information. This information can be input by the user or acquired automatically via communication. The potential control unit 62 can determine the wavelength range of the electromagnetic wave to be detected based on various pre-stored information.

[0099] Next, the photoelectric conversion unit to be operated is determined (process S13). The potential control unit 62 determines the photoelectric conversion unit to be operated, for example, based on the wavelength range determined in process S12. The potential control unit 62, for example, determines a plurality of photoelectric conversion units that are sensitive to the wavelength range determined in process S12 as the photoelectric conversion units to be operated. For example, the potential control unit 62 operates all photoelectric conversion units that are sensitive to the wavelength range determined in process S12. The potential control unit 62, for example, determines all photoelectric conversion units corresponding to the wavelength range determined in process S12 as the photoelectric conversion units to be operated.

[0100] Next, a potential is applied to the multiple photoelectric conversion units (process S14). The potential control unit 62 determines the potential applied to each electrode 51, 52, 53, and 54, for example, based on the photoelectric conversion unit to be operated. For example, the potential control unit 62 refers to a pre-stored table and obtains information associated with the photoelectric conversion unit to be operated. The potential control unit 62 determines the potential applied to each electrode 51, 52, 53, and 54 based on the obtained information.

[0101] In at least two of the plurality of photoelectric conversion units, the potential control unit 62 applies a potential lower than that applied to the first portion 37 to the second portion 38. For example, in each of the plurality of photoelectric conversion units determined in process S13, the potential control unit 62 applies a potential lower than that applied to the first portion 37 to the second portion 38. In other words, for example, the potential control unit 62 applies a forward bias voltage to all photoelectric conversion units corresponding to the wavelength range determined in process S12. For example, the potential control unit 62 applies a reverse bias voltage to all photoelectric conversion units not corresponding to the wavelength range determined in process S12.

[0102] For example, in each photoelectric conversion unit 23, 24, and 25, the potential control unit 62 applies a potential to the second part 38 that is lower than the potential applied to the first part 37. In this case, all photoelectric conversion units 23, 24, and 25 are operated. Therefore, when electromagnetic waves corresponding to any wavelength region in photoelectric conversion units 23, 24, and 25 enter the photoelectric conversion device 2, electrons are emitted from the metasurface 22.

[0103] Next, the electromagnetic wave enters the metasurface 22 (process S15). For example, the electromagnetic wave that passes through the window unit 11a of the housing 10 enters the metasurface 22.

[0104] Next, electromagnetic waves are detected based on electrons emitted from metasurface 22 (process S16). Electromagnetic wave detection device 1 detects electromagnetic waves while applying the potential determined in process S14 to each photoelectric conversion unit. For example, electromagnetic wave detection device 1 multiplies electrons emitted from electron emitter 20 and detects the multiplied electrons. As a result, electromagnetic wave detection device 1 detects electromagnetic waves entering from window unit 11a of housing 10.

[0105] Next, it is determined whether the detection process is complete (process S17). If it is determined that the detection process is not complete, the process proceeds to process S15. If it is determined that the detection process is complete, the series of processes in the electromagnetic wave detection method is completed. As described above, in Figure 6 In the electromagnetic wave detection method shown, photoelectric conversion units corresponding to the wavelength range to be detected are operated simultaneously, and the presence of electromagnetic waves within the wavelength range to be detected is detected in one step.

[0106] [Second Implementation]

[0107] Next, refer to Figure 7 The configuration of the electromagnetic wave detection device according to the second embodiment is described. This embodiment is generally similar to or the same as the embodiments and modifications described above. The second embodiment differs from the first embodiment and modifications described above in the configuration of the photoelectric conversion unit and the method of applying a potential to the electron conversion unit. In the following text, the differences from the first embodiment will be mainly described. The metasurface according to the second embodiment is also an active type, the same as the metasurface 22 according to the first embodiment.

[0108] Figure 7 This is a top view of the electron transmitter according to the second embodiment. The electron transmitter 20 according to this embodiment has a metasurface 22A. The metasurface 22A is active and operates by applying a bias voltage. The metasurface 22A operates by applying a potential via a power supply unit 60. Figure 7 In the illustrated example, metasurface 22A includes two photoelectric conversion units 23A and 24A. Photoelectric conversion units 23A and 24A correspond to electromagnetic waves with mutually different wavelength regions. In other words, multiple photoelectric conversion units 23A and 24A are sensitive to electromagnetic waves with mutually different wavelength regions.

[0109] Multiple photoelectric conversion units 23A and 24A in metasurface 22A each include patterns with different configurations. Each pattern is disposed on the main surface 21b of support 21. Each pattern has a different shape. Photoelectric conversion units 23A and 24A each include patterns 33A and 34A with different shapes. Photoelectric conversion unit 23A includes pattern 33A, and photoelectric conversion unit 24A includes pattern 34A. Each pattern 33A and 34A is a conductive line, conducting electrons. Each pattern 33A and 34A includes at least a metal layer formed on the oxide layer of metasurface 22. The material of the metal layer includes, for example, gold.

[0110] Each pattern 33A and 34A includes a plurality of first portions 37A and a plurality of second portions 38A. In this variation, each pattern 33A and 34A includes two first portions 37A and two second portions 38A. In each pattern 33A and 34A, the first portions 37A and the second portions 38A are alternately arranged in the Z-axis direction. Each first portion 37A of pattern 33A and 34A includes a front end 39A. Each second portion 38A of pattern 33A and 34A includes a front end 40A. In adjacent first portions 37A and second portions 38A, the front ends 39A and 40A face each other in the Z-axis direction. In each pattern 33A and 34A, the first portions 37A and the second portions 38A are connected via an oxide layer. In each pattern 33A and 34A, the first portions 37A and the second portions 38A are separated by an oxide layer and are insulated from each other at least when the photoelectric conversion device 2 is not in operation.

[0111] When a potential lower than that of the second part 38A is applied to the first part 37A, the first part 37A emits electrons in response to the incident electromagnetic wave. Similarly, when a potential lower than that of the first part 37A is applied to the second part 38A, the second part 38A emits electrons in response to the incident electromagnetic wave. Therefore, each photoelectric conversion unit 23A and 24A can emit electrons from either the first part 37A or the second part 38A depending on the potential state.

[0112] exist Figure 7 In the example shown, each second portion 38A in each pattern 33A and 34A includes: a plurality of linear portions 44A extending in the Z-axis direction, and a linear portion 41A extending in the Y-axis direction and connecting the plurality of linear portions 44A. The plurality of linear portions 44A extend from the linear portion 41A toward the corresponding first portion 37A. Each linear portion 44A extends from the linear portion 41A toward both the +Z-axis and -Z-axis directions. Each linear portion 44A is, for example, formed in a straight line shape. The plurality of linear portions 44A are, for example, parallel to each other. The linear portion 41A is, for example, formed in a straight line shape. Each linear portion 44A is connected to the linear portion 41A at its center.

[0113] Each first portion 37A in patterns 33A and 34A includes: a plurality of linear portions 42A extending in the Z-axis direction, and a linear portion 43A extending in the Y-axis direction and connecting the plurality of linear portions 42A. The plurality of linear portions 42A extend from the linear portion 43A toward the corresponding second portion 38A. Each linear portion 42A extends from the linear portion 43A toward the +Z-axis direction and the -Z-axis direction. Each linear portion 42A is, for example, formed in a straight line shape. The plurality of linear portions 42A are, for example, parallel to each other. The linear portion 43A is, for example, formed in a straight line shape. Each linear portion 42A is connected to the linear portion 43A at its center. The linear portions 41A and 43A in patterns 33A and 34A are, for example, parallel to each other.

[0114] exist Figure 7 In the example shown, each linear portion 42A includes a pair of front ends 39A. Each front end 39A is spaced apart from other linear portions 42A and 43A in the same pattern, and is also spaced apart from other patterns. Each linear portion 44A includes a pair of front ends 40A. Each front end 40A is spaced apart from other linear portions 44A and 41A in the same pattern, and is also spaced apart from other patterns. The front ends 39A and 40A facing each other face each other. The shortest distance between the front ends 40A and 39A facing each other is less than the shortest distance between each front end 40A and other positions in the first portion 37A other than front end 39A. The shortest distance between the front ends 39A and 40A facing each other is less than the shortest distance between each front end 39A and other positions in the second portion 38A other than front end 40A. In other words, the front end 39A is the portion of the linear portion 42A that includes the front end 39A that is closest to the corresponding linear portion 44A. The front end 40A is the portion of the linear portion 44A that is closest to the corresponding linear portion 42A. The front end 39A is configured to be closer to the linear portion 42A than other portions of the pattern that includes the front end 39A. The front end 40A is configured to be closer to the linear portion 42A than other portions of the pattern that includes the front end 40A.

[0115] In each photoelectric conversion unit 23A and 24A, the linear portion 44A of the second part 38A emits electrons in response to the incidence of electromagnetic waves when a potential lower than that of the linear portion 42A of the first part 37A is applied. In this case, the linear portion 42A constitutes a bias portion and an antenna portion. In other words, in each photoelectric conversion unit 23A and 24A, at least one of the first part 37A and the second part 38A can function as both an antenna portion and a bias portion.

[0116] The linear portions 42A of multiple patterns 33A and 34A have different lengths T4 and T5. In other words, the linear portions 42A of photoelectric conversion unit 23A and photoelectric conversion unit 24A have different lengths T4 and T5. The lengths T4 and T5 of the linear portions 42A in each pattern 33A and 34A are equal to the length in the Z-axis direction from one end point 39A to another end point 39A of each linear portion 42A.

[0117] The linear portions 44A of multiple patterns 33A and 34A have different lengths T6 and T7. In other words, the linear portions 44A of photoelectric conversion unit 23A and photoelectric conversion unit 24A have different lengths T6 and T7. The lengths T6 and T7 of the linear portions 44A in each pattern 33A and 34A are equal to the length in the Z-axis direction from one end point 40A to another end point 40A of each linear portion 44A.

[0118] In pattern 33A, the lengths T4 of the multiple linear portions 42A are the same. In pattern 34A, the lengths T5 of the multiple linear portions 42A are the same. In pattern 33A, the lengths T6 of the multiple linear portions 44A are the same. In pattern 34A, the lengths T7 of the multiple linear portions 44A are the same. When a potential lower than that of the linear portions 44A is applied to the linear portions 42A, the lengths T4 and T5 of the linear portions 42A in each pattern 33A and 34A correspond to the wavelength regions of the electromagnetic waves that cause electrons to be emitted from the photoelectric conversion units 23A and 24A. When a potential lower than that of the linear portions 42A is applied to the linear portions 44A, the lengths T6 and T7 of the linear portions 44A in each pattern 33A and 34A correspond to the wavelength regions of the electromagnetic waves that cause electrons to be emitted from the photoelectric conversion units 23A and 24A. For example, the length of each of lengths T4 and T5, or each of lengths T6 and T7, is half the length of the center wavelength of the desired wavelength region. As described above, when an electromagnetic wave passing through the support 21 enters the linear portion 42, the refractive index of the support 21 through which the electromagnetic wave passes is considered.

[0119] exist Figure 7 In the example shown, the electron emitter 20 is further provided with a plurality of electrodes 71, 72, 73, and 74 spaced apart from each other. The plurality of electrodes 71, 72, 73, and 74 are electrically connected to at least one of a plurality of photoelectric conversion units 23A and 24A. Figure 7 In the example shown, the electron transmitter 20 is provided with two electrodes 71, two electrodes 72, two electrodes 73, and two electrodes 74. Figure 7In the example shown, electrodes 71, 72, 73, and 74 are formed in a rectangular shape. As a variation, electrodes 71, 72, 73, and 74 can be formed in a straight line shape in the same manner as the first portion 37A or the second portion 38A. Electrodes 71, 72, 73, and 74 can be integrally formed with the first portion 37A or the second portion 38A.

[0120] For example, each electrode 71 is electrically connected to a first portion 37A of the photoelectric conversion unit 23A. Each electrode 72 is electrically connected to a second portion 38A of the photoelectric conversion unit 23A. Each electrode 73 is electrically connected to a first portion 37A of the photoelectric conversion unit 24A. Each electrode 74 is electrically connected to a second portion 38A of the photoelectric conversion unit 24A.

[0121] exist Figure 7 In the example shown, a potential from the power supply unit 60 is applied via multiple electrodes 71, 72, 73, and 74 to operate each photoelectric conversion unit 23A and 24A. The potential application unit 61 of the power supply unit 60 applies a potential to each photoelectric conversion unit 23A and 24A via the multiple electrodes 71, 72, 73, and 74. The potential control unit 62 of the power supply unit 60 controls the potential applied to each photoelectric conversion unit 23A and 24A.

[0122] In the electromagnetic wave detection method using the electron transmitter according to the second embodiment, for example, the following steps are performed: Figure 6 The electromagnetic wave detection method shown includes processes other than S12 and S13. In this case, the photoelectric conversion unit, which operates both photoelectric conversion unit 23A and photoelectric conversion unit 24, performs process S14.

[0123] In each pattern 33A, when the lengths of each linear portion 44A and each linear portion 42A are configured to be different from each other, process S12 is performed, and the potential applied to electrodes 71 and 72 can be changed according to a determined wavelength range. Similarly, in each pattern 34A, when the lengths of each linear portion 44A and each linear portion 42A are configured to be different from each other, process S12 is performed, and the potential applied to electrodes 73 and 74 can be changed according to a determined wavelength range.

[0124] Next, refer to Figure 8 The configuration of a modified example of the second embodiment is described. Figure 8 This is a top view of an electron emitter according to a modification of the second embodiment. In this modification, the electron emitter 20 has a metasurface 22B. The metasurface 22B is active and operates by applying a bias voltage. The metasurface 22B operates by applying a potential via a power supply unit 60. Figure 8In the example shown, metasurface 22B includes a plurality of photoelectric conversion units 23B, 24B, 25B, 26B, and 27B. Each of the plurality of photoelectric conversion units 23B, 24B, 25B, 26B, and 27B corresponds to an electromagnetic wave having a mutually different wavelength region. In other words, the plurality of photoelectric conversion units 23B, 24B, 25B, 26B, and 27B are sensitive to electromagnetic waves having mutually different wavelength regions. The photoelectric conversion units 23B, 24B, 25B, 26B, and 27B are arranged in the Y-axis direction. The photoelectric conversion units 23B, 24B, 25B, 26B, and 27B are arranged in the +Y-axis direction in the order of photoelectric conversion units 27B, 26B, 25B, 24B, and 23B.

[0125] Multiple photoelectric conversion units 23B, 24B, 25B, 26B, and 27B in metasurface 22B each include patterns with different configurations. Each pattern is disposed on the main surface 21b of the support 21. The patterns have different shapes. Photoelectric conversion unit 23B includes pattern 31B, photoelectric conversion unit 24B includes pattern 32B, photoelectric conversion unit 25B includes pattern 33B, photoelectric conversion unit 26B includes pattern 34B, and photoelectric conversion unit 27B includes pattern 35B. Each pattern 31B, 32B, 33B, 34B, and 35B contains conductive lines for conducting electrons. Each pattern 31B, 32B, 33B, 34B, and 35B includes at least a metal layer formed on the oxide layer of metasurface 22. The material of the metal layer includes, for example, gold.

[0126] Each pattern 31B, 32B, 33B, 34B, and 35B includes a first portion 37B and a second portion 38B. In this variation, each pattern 31B, 32B, 33B, 34B, and 35B includes a first portion 37B and a second portion 38B. Each first portion 37B of patterns 31B, 32B, 33B, 34B, and 35B includes a front end 39B. Each second portion 38B of patterns 31B, 32B, 33B, 34B, and 35B includes a front end 40B. In adjacent first portions 37B and second portions 38B, the front ends 39B and 40B face each other in the Z-axis direction. In each pattern 31B, 32B, 33B, 34B, and 35B, the first portion 37B and the second portion 38B are connected via an oxide layer. In each of the patterns 31B, 32B, 33B, 34B and 35B, the first part 37B and the second part 38B are separated by an oxide layer and are insulated from each other at least when the photoelectric conversion device 2 is not in operation.

[0127] The first part 37B emits electrons in response to the incidence of electromagnetic waves when a potential lower than that of the second part 38B is applied. Similarly, the second part 38B emits electrons in response to the incidence of electromagnetic waves when a potential lower than that of the first part 37B is applied. Therefore, each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B can emit electrons from either the first part 37B or the second part 38B, depending on the potential state.

[0128] exist Figure 8 In the examples shown, the first portion 37B of patterns 31B, 32B, 33B, 34B, and 35B respectively includes: linear portions 83B, 84B, 85B, 86B, and 87B extending in the Z-axis direction, and a linear portion 82B extending in the Y-axis direction and connecting the multiple linear portions 83B, 84B, 85B, 86B, and 87B. In other words, each first portion 37B of patterns 31B, 32B, 33B, 34B, and 35B is connected to each other by a linear portion 82B. The first portion 37B of pattern 31B includes linear portions 83B and 82B. The first portion 37B of pattern 32B includes linear portions 84B and 82B. The first portion 37B of pattern 33B includes linear portions 85B and 82B. The first portion 37B of pattern 34B includes linear portions 86B and 82B. The first part 37B of pattern 35B includes linear portion 87B and linear portion 82B.

[0129] Multiple linear portions 83B, 84B, 85B, 86B, and 87B extend from linear portion 82B toward the corresponding second portion 38B. Each linear portion 83B, 84B, 85B, 86B, and 87B extends from linear portion 82B in both the +Z-axis and -Z-axis directions. Each linear portion 83B, 84B, 85B, 86B, and 87B is formed, for example, in a straight line shape. For example, the multiple linear portions 83B, 84B, 85B, 86B, and 87B are parallel to each other. Linear portion 82B is formed, for example, in a straight line shape. Each linear portion 83B, 84B, 85B, 86B, and 87B is connected to linear portion 82B at its center.

[0130] The second portion 38B of patterns 31B, 32B, 33B, 34B, and 35B respectively includes: linear portions 93B, 94B, 95B, 96B, and 97B extending in the Z-axis direction, and a linear portion 92B extending in the Y-axis direction and connecting the plurality of linear portions 93B, 94B, 95B, 96B, and 97B. In other words, each second portion 38B of the linear portions 93B, 94B, 95B, 96B, and 97B is connected to each other by a linear portion 92B. The second portion 38B of pattern 31B includes linear portions 93B and 92B. The second portion 38B of pattern 32B includes linear portions 94B and 92B. The second portion 38B of pattern 33B includes linear portions 95B and 92B. The second portion 38B of pattern 34B includes linear portions 96B and 92B. The second part 38B of pattern 35B includes linear portion 97B and linear portion 92B.

[0131] Multiple linear portions 93B, 94B, 95B, 96B, and 97B extend from linear portion 92B toward the corresponding first portion 37B. Each linear portion 93B, 94B, 95B, 96B, and 97B extends from linear portion 92B in both the +Z-axis and -Z-axis directions. Each linear portion 93B, 94B, 95B, 96B, and 97B is, for example, formed in a straight line shape. For example, the multiple linear portions 93B, 94B, 95B, 96B, and 97B are parallel to each other. Linear portion 92B is, for example, formed in a straight line shape. Each linear portion 93B, 94B, 95B, 96B, and 97B is connected to linear portion 92B at its center. For example, linear portions 82B and 92B of patterns 31B, 32B, 33B, 34B, and 35B are parallel to each other.

[0132] exist Figure 8In the example shown, each linear portion 83B, 84B, 85B, 86B, and 87B includes a pair of front ends 39B. Each front end 39B is spaced apart from other linear portions of the same pattern and from other patterns. Each linear portion 93B, 94B, 95B, 96B, and 97B includes a pair of front ends 40B. Each front end 40B is spaced apart from other linear portions of the same pattern and from other patterns. The front ends 39B and 40B facing each other face each other. The shortest distance between the front ends 39B and 40B facing each other is less than the shortest distance between each front end 40B and other positions in the first portion 37B other than front end 39B. The shortest distance between the front ends 39B and 40B facing each other is less than the shortest distance between each front end 39B and other positions in the second portion 38B other than front end 40B. In other words, front end 40B is the portion of the linear portions 93B, 94B, 95B, 96B, and 97B that is closest to the corresponding linear portions 83B, 84B, 85B, 86B, and 87B. Front end 39B is the portion of the linear portions 83B, 84B, 85B, 86B, and 87B that is closest to the corresponding linear portions 93B, 94B, 95B, 96B, and 97B. Front end 39B is configured to be closer to the linear portions 93B, 94B, 95B, 96B, and 97B than other portions of the pattern including front end 39B. Front end 40B is configured to be closer to the linear portions 83B, 84B, 85B, 86B, and 87B than other portions of the pattern including front end 40B.

[0133] The shortest distance between linear portions 83B, 84B, 85B, 86B, and 87B facing each other along the Z-axis and between linear portions 93B, 94B, 95B, 96B, and 97B is constant. For example, the shortest distance between linear portions 83B and 93B included in photoelectric conversion unit 23B is the same as the shortest distance between linear portions 84B and 94B included in photoelectric conversion unit 24B.

[0134] In each of the photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, the linear portions 83B, 84B, 85B, 86B, and 87B of the first part 37B, when subjected to a potential lower than that of the linear portions 93B, 94B, 95B, 96B, and 97B of the second part 38B, emit electrons in response to the incidence of electromagnetic waves. In this case, the linear portions 93B, 94B, 95B, 96B, and 97B constitute a biasing portion, and the linear portions 83B, 84B, 85B, 86B, and 87B constitute an antenna portion. In each of the photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, the linear portions 93B, 94B, 95B, 96B, and 97B of the second portion 38B, when subjected to a potential lower than that of the linear portions 83B, 84B, 85B, 86B, and 87B of the first portion 37B, emit electrons in response to the incidence of electromagnetic waves. In this case, the linear portions 83B, 84B, 85B, 86B, and 87B constitute a bias portion, and the linear portions 93B, 94B, 95B, 96B, and 97B constitute an antenna portion. In other words, in each of the photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, at least one of the first portion 37B and the second portion 38B can serve as both an antenna portion and a bias portion.

[0135] The linear portions 83B, 84B, 85B, 86B, and 87B of multiple patterns 31B, 32B, 33B, 34B, and 35B have different lengths. For example, the length T8 of the linear portion 83B of pattern 31B and the length T9 of the linear portion 87B of pattern 35B are different from each other. The length of the linear portions 83B, 84B, 85B, 86B, and 87B in each pattern 31B, 32B, 33B, 34B, and 35B is the length in the Z-axis direction from one end 39B of each linear portion 83B, 84B, 85B, 86B, and 87B to another end 39B. For example, the length T8 is less than the length T9.

[0136] In this embodiment, the length of line portion 86B is less than the length of line portion 87B. The length of line portion 85B is less than the length of line portion 86B. The length of line portion 84B is less than the length of line portion 85B. The length of line portion 83B is less than the length of line portion 84B. In other words, line portions 87B, 86B, 85B, 84B, and 83B are configured to be shorter in the +Y axis direction.

[0137] The linear portions 93B, 94B, 95B, 96B, and 97B of multiple patterns 31B, 32B, 33B, 34B, and 35B have different lengths. For example, the length T10 of the linear portion 93B of pattern 31B and the length T11 of the linear portion 97B of pattern 35B are different from each other. The length of the linear portions 93B, 94B, 95B, 96B, and 97B in each pattern 31B, 32B, 33B, 34B, and 35B is the length in the Z-axis direction from one end point 40B of each linear portion 93B, 94B, 95B, 96B, and 97B to another end point 40B. For example, the length T10 is greater than the length T11.

[0138] In this embodiment, the length of linear portion 96B is greater than the length of linear portion 97B. The length of linear portion 95B is greater than the length of linear portion 96B. The length of linear portion 94B is greater than the length of linear portion 95B. The length of linear portion 93B is greater than the length of linear portion 94B. In other words, linear portions 97B, 96B, 95B, 94B, and 93B are configured to be longer in the +Y axis direction.

[0139] When a potential lower than that of linear portions 93B, 94B, 95B, 96B, and 97B is applied to linear portions 83B, 84B, 85B, 86B, and 87B, the lengths of linear portions 83B, 84B, 85B, 86B, and 87B correspond to the wavelength region of electromagnetic waves emitted by electrons from each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B. For example, the lengths of linear portions 83B, 84B, 85B, 86B, and 87B, or the lengths of linear portions 93B, 94B, 95B, 96B, and 97B, are half the length of the center wavelength of the desired wavelength region. As described above, when an electromagnetic wave passing through the support 21 enters the linear portion 42, the refractive index of the transmission support 21 through which the electromagnetic wave passes is considered.

[0140] exist Figure 8 In the example shown, the electron emitter 20 is also provided with a plurality of electrodes 71B and 72B spaced apart from each other. Figure 8 In the example shown, the electron emitter 20 is provided with one electrode 71B and one electrode 72B. Figure 8In the example shown, electrodes 71B and 72B are formed in a rectangular shape. As a variation, electrodes 71B and 72B can be formed in a straight line shape in the same manner as the first portion 37B or the second portion 38B. Electrodes 71B and 72B can be integrally formed with the first portion 37B or the second portion 38B.

[0141] For example, electrode 71B is electrically connected to the first portion 37B of each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B. Electrode 72B is electrically connected to the second portion 38B of each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B. Figure 8 In the example shown, each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B is operated by applying a potential from the power supply unit 60 via multiple electrodes 71B and 72B. The potential application unit 61 of the power supply unit 60 applies a potential to each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B via the multiple electrodes 71B and 72B. The potential control unit 62 of the power supply unit 60 controls the potential applied to each first portion 37B and second portion 38B.

[0142] exist Figure 8 In the example shown, linear portions 83B, 84B, 85B, 86B, and 87B, having different lengths, are interconnected via linear portion 82B. As a result, when a potential lower than that of electrode 72B is applied to electrode 71B, electrons are emitted from linear portions 83B, 84B, 85B, 86B, and 87B in response to the incident electromagnetic waves in the wavelength regions corresponding to each of the linear portions 83B, 84B, 85B, 86B, and 87B. Figure 8 In the example shown, linear portions 93B, 94B, 95B, 96B, and 97B, which have different lengths, are interconnected via linear portion 92B. As a result, when a potential lower than that of electrode 71B is applied to electrode 72B, electrons are emitted from linear portions 93B, 94B, 95B, 96B, and 97B in response to the incident electromagnetic waves in the wavelength regions corresponding to each of the linear portions 93B, 94B, 95B, 96B, and 97B.

[0143] As mentioned above, in Figure 8In the example shown, linear portions 83B, 84B, 85B, 86B, and 87B with different lengths are connected by the same linear portion 82B. Linear portions 93B, 94B, 95B, 96B, and 97B with different lengths are connected by the same linear portion 92B. According to this configuration, a wider wavelength range of electromagnetic waves that can be converted into electrons can be ensured through a more compact arrangement. In other words, despite the more compact configuration, electromagnetic waves with different wavelength components can be detected simultaneously. Furthermore, the shortest distance between the linear portions 83B, 84B, 85B, 86B, and 87B facing each other in the Z-axis direction and the linear portions 93B, 94B, 95B, 96B, and 97B is constant. As a result, electromagnetic wave sensitivity can be ensured in each photoelectric conversion unit 23B, 24B, 25B, 26B, and 27B.

[0144] Next, refer to Figure 9 This describes the configuration of another variation of the second embodiment. Figure 9 This is a top view of an electron emitter according to a variation of the second embodiment. In this variation, the electron emitter 20 has a metasurface 22C. The metasurface 22C is also active and operates by applying a bias voltage. This variation is similar to... Figure 8 The examples shown are largely similar or identical. The antenna section of metasurface 22B includes a dipole antenna, while the antenna section of metasurface 22C includes a diamond antenna. The following description primarily focuses on... Figure 8 The variations shown are and Figure 9 The differences between the variant examples shown.

[0145] exist Figure 9 In the example shown, metasurface 22C includes multiple photoelectric conversion units 23C, 24C, 25C, and 26C. These multiple photoelectric conversion units 23C, 24C, 25C, and 26C each correspond to electromagnetic waves having different wavelength regions. In other words, the multiple photoelectric conversion units 23C, 24C, 25C, and 26C are sensitive to electromagnetic waves within their respective wavelength regions. The photoelectric conversion units 23C, 24C, 25C, and 26C are arranged in the +Y axis direction in the order of photoelectric conversion units 26C, 25C, 24C, and 23C.

[0146] Photoelectric conversion unit 23C includes pattern 31C, photoelectric conversion unit 24C includes pattern 32C, photoelectric conversion unit 25C includes pattern 33C, and photoelectric conversion unit 26C includes pattern 34C. Each pattern 31C, 32C, 33C, and 34C corresponds to each pattern 31B, 32B, 33B, and 34B, and is made of the same material as each pattern 31B, 32B, 33B, and 34B.

[0147] Each pattern 31C, 32C, 33C, and 34C includes a first portion 37C and a second portion 38C. Each first portion 37C of patterns 31C, 32C, 33C, and 34C includes a front end 39C. Each second portion 38C of patterns 31C, 32C, 33C, and 34C includes a front end 40C. Each first portion 37C corresponds to each first portion 37B, and each second portion 38C corresponds to each second portion 38B. The front end 39C corresponds to the front end 39B, and the front end 40C corresponds to the front end 40B.

[0148] exist Figure 9 In the example shown, the first portion 37C of patterns 31C, 32C, 33C, and 34C respectively includes: rhomboid portions 83C, 84C, 85C, and 86C extending in the Z-axis direction, and a linear portion 82C extending in the Y-axis direction and connecting multiple rhomboid portions 83C, 84C, 85C, and 86C. Linear portion 82C corresponds to linear portion 82B. Rhomboid portions 83C, 84C, 85C, and 86C correspond to linear portions 83B, 84B, 85B, and 86B.

[0149] Multiple rhomboid portions 83C, 84C, 85C, and 86C extend from the linear portion 82C toward the corresponding second portion 38C. Each rhomboid portion 83C, 84C, 85C, and 86C extends from the linear portion 82C in both the +Z-axis and -Z-axis directions. Each rhomboid portion 83C, 84C, 85C, and 86C is connected to the linear portion 82C at its center. For example, the linear portion 82C is connected to two vertices of each rhomboid portion 83C, 84C, 85C, and 86C.

[0150] exist Figure 9 In the example shown, the second part 38C of patterns 31C, 32C, 33C, and 34C respectively includes: rhomboid portions 93C, 94C, 95C, and 96C extending in the Z-axis direction, and a linear portion 92C extending in the Y-axis direction and connecting multiple rhomboid portions 93C, 94C, 95C, and 96C. Linear portion 92C corresponds to linear portion 92B. Rhomboid portions 93C, 94C, 95C, and 96C correspond to linear portions 93B, 94B, 95B, and 96B. The difference between rhomboid portions 93C, 94C, 95C, and 96C and linear portions 93B, 94B, 95B, and 96B is that they are formed in a rhomboid shape.

[0151] Multiple rhomboid portions 93C, 94C, 95C, and 96C extend from the linear portion 92C toward their corresponding first portions 37C. Each rhomboid portion 93C, 94C, 95C, and 96C extends from the linear portion 92C in both the +Z-axis and -Z-axis directions. Each rhomboid portion 93C, 94C, 95C, and 96C is connected to the linear portion 92C at its center. For example, the linear portion 92C is connected to two vertices of each rhomboid portion 93C, 94C, 95C, and 96C.

[0152] In each photoelectric conversion unit 23C, 24C, 25C, and 26C, the rhomboid portions 83C, 84C, 85C, and 86C of the first part 37C emit electrons in response to the incidence of electromagnetic waves when a potential lower than that of the rhomboid portions 93C, 94C, 95C, and 96C of the second part 38C is applied. In this case, the rhomboid portions 93C, 94C, 95C, and 96C constitute a biasing portion, and the rhomboid portions 83C, 84C, 85C, and 86C constitute an antenna portion. In this case, the rhomboid portions 83C, 84C, 85C, and 86C are configured as a bow-tie antenna.

[0153] In each of the photoelectric conversion units 23C, 24C, 25C, and 26C, the rhomboid portions 93C, 94C, 95C, and 96C of the second part 38C emit electrons in response to the incidence of electromagnetic waves when a potential lower than that of the rhomboid portions 83C, 84C, 85C, and 86C of the first part 37C is applied. In this case, the rhomboid portions 83C, 84C, 85C, and 86C constitute a bias portion, and the rhomboid portions 93C, 94C, 95C, and 96C constitute an antenna portion. In this case, the rhomboid portions 93C, 94C, 95C, and 96C constitute a bowtie antenna. In other words, in each of the photoelectric conversion units 23C, 24C, 25C, and 26C, at least one of the first part 37C and the second part 38C can serve as both an antenna portion and a bias portion.

[0154] The rhomboid portions 83C, 84C, 85C, and 86C of multiple patterns 31C, 32C, 33C, and 34C have different lengths. For example, the length T12 of the rhomboid portion 83C of pattern 31C and the length T13 of the rhomboid portion 86C of pattern 34C are different from each other. The length of the rhomboid portions 83C, 84C, 85C, and 86C in each pattern 31C, 32C, 33C, and 34C is the length in the Z-axis direction from one front end 39C of each rhomboid portion 83C, 84C, 85C, and 86C to another front end 39C. For example, the length T12 is greater than the length T13.

[0155] In this embodiment, the length of rhombus portion 85C is greater than the length of rhombus portion 86C. The length of rhombus portion 84C is greater than the length of rhombus portion 85C. The length of rhombus portion 83C is greater than the length of rhombus portion 84C. In other words, rhombus portions 86C, 85C, 84C, and 83C are configured to be longer in the +Y axis direction.

[0156] The rhomboid portions 93C, 94C, 95C, and 96C of multiple patterns 31C, 32C, 33C, and 34C have different lengths. For example, the length T14 of the rhomboid portion 93C of pattern 31C and the length T15 of the rhomboid portion 96C of pattern 34C are different from each other. The length of the rhomboid portions 93C, 94C, 95C, and 96C in each pattern 31C, 32C, 33C, and 34C is the length in the Z-axis direction from one end 40C of each rhomboid portion 93C, 94C, 95C, and 96C to another end 40C.

[0157] In this embodiment, the length of rhombus portion 95C is less than the length of rhombus portion 96C. The length of rhombus portion 94C is less than the length of rhombus portion 95C. The length of rhombus portion 93C is less than the length of rhombus portion 94C. In other words, rhombus portions 96C, 95C, 94C, and 93C are configured to be shorter in the +Y axis direction.

[0158] exist Figure 9 In the example shown, the electron transmitter 20 is also provided with a plurality of electrodes 71C and 72C spaced apart from each other. Figure 9 In the example shown, electrode 71C corresponds to electrode 71B, and electrode 72C corresponds to electrode 72B.

[0159] As mentioned above, in Figure 9 In the example shown, rhomboid portions 83C, 84C, 85C, and 86C, which have different lengths, are connected by the same linear portion 82C. Rhomboid portions 93C, 94C, 95C, and 96C, which have different lengths, are connected by the same linear portion 92B. According to the above configuration, a more compact arrangement ensures the wavelength range of electromagnetic waves that can be converted into electrons. Furthermore, the shortest distance between the rhomboid portions 83C, 84C, 85C, and 86C facing each other in the Z-axis direction and the rhomboid portions 93C, 94C, 95C, and 96C is constant. As a result, electromagnetic wave sensitivity can be ensured in each photoelectric conversion unit 23C, 24C, 25C, and 26C.

[0160] exist Figure 9 In the example shown, metasurface 22C replaces the dipole antenna with a rhombic antenna as the antenna section. The rhombic antenna has a wider wavelength range of sensitivity than the dipole antenna. As a result, electromagnetic waves with mutually different wavelength components can be detected simultaneously, despite a more compact configuration.

[0161] [Third Implementation Method]

[0162] Next, refer to Figure 10 The configuration of the electromagnetic wave detection device according to the third embodiment is described. Figure 10 This is a perspective view of the electromagnetic wave detection device according to the second embodiment. This embodiment is generally similar to or the same as the embodiments and modifications described above. The difference between this embodiment and the embodiments and modifications described above is that the metasurface is passive. In the following description, the differences from the embodiments described above will be mainly described.

[0163] The electromagnetic wave detection device 1D includes a photoelectric conversion device 2D. The photoelectric conversion device 2D emits electrons in response to the incidence of electromagnetic waves. In this embodiment, the electromagnetic wave detection device 1D detects incoming electromagnetic waves based on the electrons emitted from the photoelectric conversion device 2D in response to the incidence of electromagnetic waves.

[0164] The electromagnetic wave detection device 1D includes a housing 10, an electron transmitter 20D, a holder 30, an electron multiplier unit 40, and an electron collection unit 50. The electron transmitter 20D, holder 30, electron multiplier unit 40, and electron collection unit 50 are disposed within the housing 10. The photoelectric conversion device 2D includes the housing 10 and the electron transmitter 20D, and constitutes part of the electromagnetic wave detection device 1D. The electromagnetic wave detection device 1D according to this embodiment does not include a power supply unit 60.

[0165] Electron emitter 20D emits electrons in response to the incidence of electromagnetic waves. Electron emitter 20D has a metasurface 22D. Metasurface 22D is passive and operates without the application of a bias voltage. Metasurface 22D is disposed in support 21. Metasurface 22D emits electrons in response to the incidence of electromagnetic waves.

[0166] Metasurface 22D includes, for example, an oxide layer formed on the main surface 21b of the support 21 and a metal layer formed on the oxide layer. The oxide layer is made of materials such as silicon dioxide and titanium dioxide. For example, the oxide layer includes a silicon dioxide-containing layer and a titanium dioxide-containing layer. The metal layer is made of materials such as gold. In this embodiment, the oxide layer is formed on the main surface 21b of the support 21, which is made of quartz, and the metal layer is formed on the oxide layer. For example, the thickness of the support 21 is 525 μm, the thickness of the silicon dioxide layer of the metasurface 22 is 1 μm, the thickness of the titanium dioxide-containing layer of the metasurface 22 is 10 nm, and the thickness of the metal layer of the metasurface 22 is 200 nm. The metasurface 22D is formed in a rectangular shape in a top view. In a variation of this embodiment, the metasurface 22D may be disposed on the main surface 21a.

[0167] Next, refer to Figure 11A and11B The photoelectric conversion device 2D is described in further detail. Figure 11A This is a top view of the electron emitter according to the third embodiment. The metasurface 22D includes a plurality of photoelectric conversion units 23D, 24D, 25D, and 26D. The photoelectric conversion units 23D, 24D, 25D, and 26D are arranged in the Z-axis direction.

[0168] Multiple photoelectric conversion units 23D, 24D, 25D, and 26D emit electrons in response to incident light of their respective corresponding wavelengths. Photoelectric conversion units 23D and 25D, as well as 24D and 26D, correspond to electromagnetic waves with mutually different wavelength regions. In other words, photoelectric conversion units 23D and 25D, as well as 24D and 26D, are sensitive to electromagnetic waves with mutually different wavelength regions. Photoelectric conversion units 23D and 25D correspond to electromagnetic waves within the same wavelength region. Photoelectric conversion units 24D and 26D correspond to electromagnetic waves within the same wavelength region.

[0169] Photoelectric conversion units 23D, 24D, 25D, and 26D have equal potentials. Photoelectric conversion units 23D, 24D, 25D, and 26D are electrically connected to each other. As a variation of this embodiment, photoelectric conversion units 23D, 24D, 25D, and 26D may not be electrically connected to each other, but may be connected to, for example, the same potential, ground.

[0170] In this embodiment, with Figure 2 In the same manner as the example shown, electromagnetic waves W entering housing 10 enter photoelectric conversion units 23D, 24D, 25D, and 26D. As a result, photoelectric conversion units 23D, 24D, 25D, and 26D corresponding to the wavelength of electromagnetic wave W emit electrons in response to the incident electromagnetic wave W. Electrons emitted from at least one of photoelectric conversion units 23D, 24D, 25D, and 26D are incident on electron multiplication unit 40. Electrons multiplied in electron multiplication unit 40 are collected in electron collection unit 50.

[0171] like Figure 11AAs shown, photoelectric conversion units 23D and 25D, and photoelectric conversion units 24D and 26D include patterns 33D, 34D, 35D, and 36D with mutually different configurations. Patterns 33D and 35D of photoelectric conversion units 23D and 25D, and patterns 34D and 36D of photoelectric conversion units 24D and 26D, have mutually different shapes. Photoelectric conversion units 23D and 25D include patterns 33D and 35D with the same shape. Photoelectric conversion units 24D and 26D include patterns 34D and 36D with the same shape. Each pattern 33D, 34D, 35D, and 36D is a conductive line and conducts electrons. Each pattern 33D, 34D, 35D, and 36D includes at least a metal layer formed on the oxide layer of the metasurface 22. The material of the metal surface includes, for example, gold. Patterns 33D, 34D, 35D, and 36D have equal potentials.

[0172] The electron transmitter 20D is also provided with a frame pattern 110D. The frame pattern 110D is electrically connected to each of the patterns 33D, 34D, 35D, and 36D. Patterns 33D, 34D, 35D, and 36D are electrically connected to each other via the frame pattern 110D. The frame pattern 110D is disposed on the main surface 21b of the support 21. The frame pattern 110D is disposed along the edge of the main surface 21b to surround patterns 33D, 34D, 35D, and 36D. The frame pattern 110D is, for example, formed in a rectangular frame shape.

[0173] Each pattern 33D, 34D, 35D, and 36D includes: a plurality of linear portions 42D extending in the Z-axis direction, and a linear portion 43D extending in the Y-axis direction and connecting the plurality of linear portions 42D. Each linear portion 42D and 43D is formed, for example, in a straight line shape. For example, the plurality of linear portions 42D are parallel to each other. The plurality of linear portions 42D have a front end 39D. The front end 39D of each pattern 33D, 34D, 35D, and 36D is spaced apart from other linear portions 42D and 43D in the same pattern, and is also spaced apart from other patterns. Although in Figure 11A Not shown, but each of patterns 33D, 34D, 35D, and 36D may include: a line portion facing the front end 39D and connected to the line portion 43D. Although in Figure 11A Not shown, but each pattern 33D, 34D, 35D and 36D may include a line portion configured to surround each line portion 42D.

[0174] Each linear portion 42D emits electrons in response to the incidence of electromagnetic waves. In other words, the linear portions 42D constitute antenna portions. The smaller the size of the antenna portion, the more likely it is to generate field electron emission for electromagnetic waves with shorter wavelengths, i.e., electromagnetic waves with higher frequencies. The photoelectric conversion units 23D, 25D, 24D, and 26D of the metasurface 22D are configured to correspond to, for example, a frequency range between approximately 0.01 and 150 THz, i.e., the frequency range between millimeter waves and infrared light, by changing the configuration of the linear portions 42D.

[0175] At least two of the photoelectric conversion units 23D, 25D, 24D, and 26D have linear portions 42D with different lengths. For example, the linear portions 42D of photoelectric conversion units 23D and 25D, and the linear portions 42D of photoelectric conversion units 24D and 26D, have different lengths T16 and T17. The lengths T16 and T17 of the linear portions 42D in each pattern 33D, 34D, 35D, and 36D are the lengths from one end point 39D of the linear portion 42D to the other end point 39D in the Z-axis direction.

[0176] In patterns 33D and 35D, the lengths T16 of the multiple linear portions 42D are the same. In patterns 34D and 36D, the lengths T17 of the multiple linear portions 42D are the same. The lengths T16 and T17 of the linear portions 42D in patterns 33D, 34D, 35D, and 36D correspond to the wavelength regions of the electromagnetic waves emitted by electrons in each photoelectric conversion unit 23D, 24D, 25D, and 26D.

[0177] Figure 11B This is a top view of an electron emitter according to a modified example of this embodiment. The metasurface 22E includes a plurality of photoelectric conversion units 23E, 24E, 25E, and 26E. When viewed from the X-axis direction, the photoelectric conversion units 23E, 24E, 25E, and 26E are arranged in a matrix-like manner.

[0178] Multiple photoelectric conversion units 23E, 24E, 25E, and 26E emit electrons in response to incident radiation of corresponding wavelengths. Photoelectric conversion units 23E and 25E, as well as 24E and 26E, correspond to electromagnetic waves with wavelength regions different from each other. In other words, photoelectric conversion units 23E and 25E, as well as 24E and 26E, are sensitive to electromagnetic waves with different wavelength regions. Photoelectric conversion units 23E and 25E correspond to electromagnetic waves within the same wavelength region. Photoelectric conversion units 24E and 26E correspond to electromagnetic waves within the same wavelength region. Photoelectric conversion units 23E, 24E, 25E, and 26E have equal potentials. Photoelectric conversion units 23E, 24E, 25E, and 26E are electrically connected to each other.

[0179] In this variation, with Figure 2 In the same manner as the example shown, electromagnetic waves W entering housing 10 enter photoelectric conversion units 23E, 24E, 25E, and 26E. As a result, photoelectric conversion units 23E, 24E, 25E, and 26E corresponding to the wavelength of electromagnetic wave W emit electrons in response to the incident electromagnetic wave W. Electrons emitted from at least one of photoelectric conversion units 23E, 24E, 25E, and 26E enter electron multiplication unit 40. Electrons multiplied in electron multiplication unit 40 are collected in electron collection unit 50.

[0180] like Figure 11B As shown, photoelectric conversion units 23E and 25E, as well as photoelectric conversion units 24E and 26E, include patterns 33E, 34E, 35E, and 36E with mutually different configurations. Patterns 33E and 35E of photoelectric conversion units 23E and 25E, and patterns 34E and 36E of photoelectric conversion units 24E and 26E, have mutually different shapes. Photoelectric conversion units 23E and 25E include patterns 33E and 35E with the same shape. Photoelectric conversion units 24E and 26E include patterns 34E and 36E with the same shape. Each pattern 33E, 34E, 35E, and 36E is a conductive line and conducts electrons. Each pattern 33E, 34E, 35E, and 36E includes at least a metal layer formed on the oxide layer of the metasurface 22. The material of the metal layer includes, for example, gold. Patterns 33E, 34E, 35E, and 36E have equal potentials.

[0181] In this modified example, the electron transmitter 20E is further provided with four interconnected frame patterns 110E. Each frame pattern 110E is electrically connected to each pattern 33E, 34E, 35E, and 36E. Patterns 33E, 34E, 35E, and 36E are electrically connected to each other via each frame pattern 110E. Each frame pattern 110E is disposed on the main surface 21b of the support 21. Each frame pattern 110E is configured to surround the corresponding pattern 33E, 34E, 35E, and 36E. Each frame pattern 110E is, for example, formed in a rectangular frame shape. The regions where photoelectric conversion units 23E, 24E, 25E, and 26E are disposed are divided by each frame pattern 110E.

[0182] Each pattern 33E, 34E, 35E, and 36E includes: a plurality of linear portions 42D extending in the Z-axis direction, and a linear portion 43D extending in the Y-axis direction and connecting the plurality of linear portions 42D. The front ends 39D of the plurality of linear portions 42D are spaced apart from other linear portions 42D and linear portions 43D having the same pattern, and are also spaced apart from other patterns. Although not in Figure 9D is not shown, but each of the patterns 33E, 34E, 35E, and 36E may include a line portion facing the front end 39D and connected to the line portion 43D. Although in Figure 11B Not shown, but each pattern 33E, 34E, 35E and 36E may include: a line portion configured to surround each linear portion 42D.

[0183] The linear portions 42D of photoelectric conversion units 23E and 25E, and the linear portions 42D of photoelectric conversion units 24E and 26E, have different lengths T18 and T19. In patterns 33E and 35E, the lengths T18 of multiple linear portions 42D are the same. In patterns 34E and 36E, the lengths T19 of multiple linear portions 42D are the same. The lengths T18 and T19 of the linear portions 42D in patterns 33E, 34E, 35E, and 36E correspond to the wavelength regions of electromagnetic waves emitted by electrons in photoelectric conversion units 23E, 24E, 25E, and 26E.

[0184] As a variation of the third embodiment, metasurface 22D can replace photoelectric conversion units 23D, 24D, 25D, and 26D, and has at least one of photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, and photoelectric conversion units 23C, 24C, 25C, and 26C, as in the variation of the second embodiment. For example, when metasurface 22D replaces photoelectric conversion units 23D, 24D, 25D, and 26D and has photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, Figure 8 The two ends of the linear portions 82B and 92B shown are connected to the frame pattern 110D. In the case where the metasurface 22D replaces the photoelectric conversion units 23D, 24D, 25D, and 26D, and has photoelectric conversion units 23C, 24C, 25C, and 26C, Figure 9 The two ends of the linear portions 82C and 92C shown are connected to the frame pattern 110D.

[0185] Similarly, metasurface 22E can replace photoelectric conversion units 23E, 24E, 25E, and 26E to have at least one of photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, and photoelectric conversion units 23C, 24C, 25C, and 26C, as described in the modified example of the second embodiment. For example, in the case where metasurface 22E replaces photoelectric conversion units 23E, 24E, 25E, and 26E to have photoelectric conversion units 23B, 24B, 25B, 26B, and 27B, Figure 8 The two ends of the linear portions 82B and 92B shown are connected to the frame pattern 110E. In the case where the metasurface 22E replaces the photoelectric conversion units 23E, 24E, 25E, and 26E, and has photoelectric conversion units 23C, 24C, 25C, and 26C, Figure 9The two ends of the linear portions 82C and 92C shown are connected to the frame pattern 110E.

[0186] [Functions and Effects]

[0187] In photoelectric conversion devices 2 and 2D, electron emitters 20, 20D, and 20E include metasurfaces 22, 22A, 22B, 22C, 22D, and 22E that emit electrons in response to the incidence of electromagnetic waves. Each metasurface 22, 22A, 22B, 22C, 22D, and 22E includes multiple photoelectric conversion units sensitive to electromagnetic waves having mutually different wavelength regions. For example, the multiple photoelectric conversion units 23, 24, and 25 of metasurface 22 include patterns 33, 34, and 35 with mutually different configurations. Photoelectric conversion units 23 and 24 of metasurface 22 include patterns 33 and 34 with mutually different shapes. It is assumed that the shapes of patterns 33 and 34 in each photoelectric conversion unit 23 and 24 are associated with the wavelength region of the electromagnetic waves that cause electrons to be emitted in each photoelectric conversion unit 23 and 24. The multiple photoelectric conversion units 23 and 24 are sensitive to electromagnetic waves having mutually different wavelength regions. Therefore, photoelectric conversion device 2 is sensitive to electromagnetic waves with wavelengths corresponding to photoelectric conversion unit 23 and photoelectric conversion unit 24. According to the above configuration, photoelectric conversion unit 23 emits electrons in response to the incident electromagnetic wave within its wavelength range, and photoelectric conversion unit 24 emits electrons in response to the incident electromagnetic wave within its wavelength range. This also applies to photoelectric conversion device 2B. As described above, in photoelectric conversion devices 2 and 2D, the wavelength range of electromagnetic waves that can be converted into electrons is expanded.

[0188] Electromagnetic wave detection devices 1 and 1D, equipped with photoelectric conversion devices 2 and 2D, do not require cooling, nor do they require beam splitters or filters. In photoelectric conversion devices 2 and 2D, the metasurfaces 22, 22A, 22B, 22C, 22D, and 22E, which emit electrons in response to the incidence of electromagnetic waves, are enlarged simply by enlarging the patterned area. Therefore, in electromagnetic wave detection devices 1 and 1D, the area where electromagnetic waves enter can be enlarged more easily and cheaper compared to detection devices using beam splitters or filters.

[0189] The photoelectric conversion device 2 includes active metasurfaces 22, 22A, 22B, and 22C that operate by applying an electric potential. For example, in the metasurface 22 of the photoelectric conversion device 2, the patterns 33 and 34 of the photoelectric conversion units 23 and 24 include a first portion 37 and a second portion 88 spaced apart from each other. The second portion 38 includes a front end 39 facing the first portion 37. When the second portion 38 is subjected to a potential lower than that of the first portion 37, it emits electrons in response to the incidence of electromagnetic waves. In this case, the sensitivity of each photoelectric conversion unit 23 and 24 is improved.

[0190] Furthermore, in the metasurface 22, the photoelectric conversion unit to be operated can be switched by controlling the application of a potential to the first portion 37 and the second portion 38. For example, since multiple photoelectric conversion units 23 and 24 emit electrons in response to the incident electromagnetic waves having different wavelength regions, the wavelength region that causes electron emission can be switched by controlling the photoelectric conversion unit to be operated. Therefore, the wavelength range of the electromagnetic waves that cause electrons to be emitted in the photoelectric conversion device 2 can be controlled by controlling the application of a potential to the first portion 37 and the second portion 38. The photoelectric conversion device 2 can also emit electrons in response to the incident electromagnetic waves having wavelength components corresponding to the wavelength regions of each photoelectric conversion unit, without any optical elements such as beam splitters and filters.

[0191] For example, in the same manner as spectral detection, the electromagnetic wave detection device 1, which includes the photoelectric conversion device 2 described above, can detect electromagnetic waves corresponding to each wavelength region of each photoelectric conversion unit 23 and 24. The electromagnetic wave detection device 1, for example, can detect the presence of electromagnetic waves having wavelength components in multiple wavelength regions at once. The electromagnetic wave detection device 1 can also amplify or reduce the wavelength range of the electromagnetic wave to be detected as needed.

[0192] For example, in the metasurface 22 of the photoelectric conversion device 2, the second portion 38 of each photoelectric conversion unit 23 and 24 includes a linear portion 42 extending toward the first portion 37. The linear portions 42 of photoelectric conversion unit 23 and photoelectric conversion unit 24 have different lengths. The wavelength range of the electromagnetic waves emitted by electrons in each photoelectric conversion unit 23 and 24 is changed according to the length of the linear portion 42. Therefore, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device 2 can be expanded by a simple configuration.

[0193] For example, in multiple photoelectric conversion units 23 and 24, a first portion 37 or a second portion 38 of photoelectric conversion unit 23 is electrically connected to a first portion 37 or a second portion 38 of photoelectric conversion unit 24. In metasurface 22, a second portion 38 of photoelectric conversion unit 23 is electrically connected to a second portion 38 of photoelectric conversion unit 24. In this case, the wavelength range of electromagnetic waves that can be converted into electrons in photoelectric conversion device 2 can be expanded by a simple configuration.

[0194] The photoelectric conversion device 2 is, for example, provided with a potential control unit 62 that controls the potential applied to the first part 37 and the second part 38 of each photoelectric conversion unit 23, 24 and 25. In this case, the photoelectric conversion unit to be operated can be selected by the potential control unit 62.

[0195] The potential control unit 62 controls, for example, the potentials applied to the first and second portions 37 and 38 of the photoelectric conversion unit 23, and the first and second portions 37 and 38 of the photoelectric conversion unit 24. The potential difference between the potential applied to the first portion 37 of the photoelectric conversion unit 23 and the potential applied to the second portion 38 of the photoelectric conversion unit 23, and the potential difference between the potential applied to the first portion 37 of the photoelectric conversion unit 24 and the potential applied to the second portion 38 of the photoelectric conversion unit 24, can be different from each other. In this case, the photoelectric conversion unit 23 and the photoelectric conversion unit 24 can operate independently. Therefore, the photoelectric conversion device 2 can change the wavelength range of the electromagnetic wave that can be converted into electrons. In other words, the photoelectric conversion device 2 emits electrons in response to the incident electromagnetic wave having wavelength components in a desired wavelength region among multiple wavelength regions corresponding to the multiple photoelectric conversion units. Therefore, for example, in the same manner as spectral detection, the electromagnetic wave detection device 1 can detect electromagnetic waves corresponding to each wavelength region of each photoelectric conversion unit 23 and 24. The electromagnetic wave detection device 1 can amplify or reduce the wavelength range of the electromagnetic wave to be detected as appropriate.

[0196] For example, when a potential lower than that applied to the first portion 37 of the photoelectric conversion unit 24 is applied to the second portion 38 of the photoelectric conversion unit 24, the potential control unit 62 applies a potential higher than that applied to the first portion 37 of the photoelectric conversion unit 23 to the second portion 38 of the photoelectric conversion unit 23. In this case, when the photoelectric conversion unit 24 is configured to emit electrons in response to the incident electromagnetic wave, the emission of electrons in response to the incident electromagnetic wave from the photoelectric conversion unit 23 can be safely stopped.

[0197] For example, in at least two of the multiple photoelectric conversion units 23, 24, and 25, the potential control unit 62 applies a potential lower than that applied to the first portion 37 to the second portion 38. In this case, at least two photoelectric conversion units operate simultaneously. Therefore, for example, the conversion of electromagnetic waves to electrons within the wavelength region corresponding to photoelectric conversion unit 23 and the conversion of electromagnetic waves to electrons within the wavelength region corresponding to photoelectric conversion unit 24 can be performed simultaneously. Therefore, the electromagnetic wave detection device 1 can, for example, detect the presence of electromagnetic waves having wavelength components in multiple wavelength regions at once.

[0198] The photoelectric conversion device 2D has passive metasurfaces 22D and 22E that operate without an applied potential. In this configuration, the electromagnetic wave detection device 1D with the photoelectric conversion device 2D can, for example, detect the presence of electromagnetic waves with wavelength components in multiple wavelength regions simultaneously. In the photoelectric conversion device 2D, the patterns 33D and 33E of the photoelectric conversion units 23D and 23E, and the patterns 34D and 34E of the photoelectric conversion units 24D and 24E, have equal potentials. In this configuration, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device 2B can be expanded through a simpler arrangement.

[0199] In the photoelectric conversion device 2D, the patterns 33D and 33E of photoelectric conversion units 23D and 23E, and the patterns 34D and 34E of photoelectric conversion units 24D and 24E, are electrically connected to each other. In this case, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device 2D can be expanded by a simpler configuration.

[0200] In the photoelectric conversion device 2D, the patterns of each photoelectric conversion unit 23D, 25D, 24D, and 26D include linear portions. The linear portions 42D of at least two of the photoelectric conversion units 23D, 25D, 24D, and 26D have different lengths. For example, the linear portions 42D of photoelectric conversion units 23D and 23E, and the linear portions 42D of photoelectric conversion units 24D and 24E, have different lengths. The wavelength range of the electromagnetic waves emitted by electrons in each photoelectric conversion unit is varied according to the length of the linear portions 42D. As a result, the wavelength range of electromagnetic waves that can be converted into electrons in the photoelectric conversion device 2D can be expanded with a simpler configuration.

[0201] Electromagnetic wave detection devices 1 and 1D are also provided with a housing 10 that is hermetically sealed and has a window unit 11a that transmits electromagnetic waves. Electron emitters 20 and 20D are disposed in the housing 10. In this case, the amount of electrons emitted in response to the incident electromagnetic waves can be increased by evacuating the housing 10 or by filling the housing 10 with gas.

Claims

1. A photoelectric conversion device, wherein, It possesses: an electron emitter comprising a metasurface that emits electrons in response to the incidence of electromagnetic waves, wherein The metasurface includes multiple photoelectric conversion units that are sensitive to electromagnetic waves with mutually different wavelength regions, and The plurality of photoelectric conversion units each include patterns with different configurations. The pattern of each of the photoelectric conversion units includes first and second portions spaced apart from each other, and The second portion includes a front end facing the first portion and is configured to emit electrons in response to the incident electromagnetic wave when a potential lower than that of the first portion is applied to the second portion. The second portion of each of the photoelectric conversion units includes a linear portion extending toward the first portion, and The linear portions of at least two of the plurality of photoelectric conversion units have different lengths from each other.

2. The photoelectric conversion device according to claim 1, wherein, In two of the plurality of photoelectric conversion units, the first or second part of one photoelectric conversion unit is electrically connected to the first or second part of the other photoelectric conversion unit.

3. The photoelectric conversion device according to claim 1, wherein, It also includes: a potential control unit configured to control the potential applied to the first and second portions of each of the photoelectric conversion units.

4. The photoelectric conversion device according to claim 3, wherein, The plurality of photoelectric conversion units include: a first photoelectric conversion unit and a second photoelectric conversion unit. The potential control unit is configured to control the potential applied to the first and second portions of the first photoelectric conversion unit and the first and second portions of the second photoelectric conversion unit, and The potential difference between the potential applied to the first part of the first photoelectric conversion unit and the potential applied to the second part of the first photoelectric conversion unit, and the potential difference between the potential applied to the first part of the second photoelectric conversion unit and the potential applied to the second part of the second photoelectric conversion unit are different from each other.

5. The photoelectric conversion device according to claim 4, wherein, When a potential lower than that applied to the first portion of the second photoelectric conversion unit is applied to the second portion of the second photoelectric conversion unit, the potential control unit is configured to apply a potential higher than that applied to the first portion of the first photoelectric conversion unit to the second portion of the first photoelectric conversion unit.

6. The photoelectric conversion device according to claim 3, wherein, For at least two of the photoelectric conversion units, the potential control unit is configured to apply a potential lower than that applied to the first part to the second part.

7. The photoelectric conversion device according to claim 1, wherein, The patterns of each photoelectric conversion unit have the same potential.

8. The photoelectric conversion device according to claim 1, wherein, The patterns of each photoelectric conversion unit are electrically connected to each other.

9. The photoelectric conversion device according to any one of claims 1 to 8, wherein, It also includes: a housing configured to be airtight and having a window that transmits the electromagnetic waves, wherein, The electron transmitter is disposed within the housing.

10. A photoelectric conversion method, in, include: The electromagnetic wave to be measured is introduced into a metasurface comprising multiple photoelectric conversion units, each comprising a pattern having a different configuration; and Electrons are emitted from at least one photoelectric conversion unit among the plurality of photoelectric conversion units that corresponds to the wavelength region of the electromagnetic wave to be measured. The pattern of each photoelectric conversion unit includes: a first portion, and a second portion spaced apart from the first portion and having a front end facing the first portion. When a potential lower than that applied to the first portion is applied to the second portion, each of the photoelectric conversion units emits electrons in response to the incident electromagnetic wave. The second portion of each of the photoelectric conversion units includes a linear portion extending toward the first portion, and The linear portions of at least two of the plurality of photoelectric conversion units have different lengths from each other.

11. The photoelectric conversion method according to claim 10, wherein, It also includes: controlling the potential applied to the plurality of photoelectric conversion units, wherein, Control the potential applied to the first and second portions of each of the photoelectric conversion units.

12. The photoelectric conversion method according to claim 11, wherein, The potential applied to the first photoelectric conversion unit and the second photoelectric conversion unit included in the plurality of photoelectric conversion units is controlled such that the potential difference between the potential applied to the first part of the first photoelectric conversion unit and the potential applied to the second part of the first photoelectric conversion unit is different from the potential difference between the potential applied to the first part of the second photoelectric conversion unit and the potential applied to the second part of the second photoelectric conversion unit.

13. The photoelectric conversion method according to claim 12, wherein, When a potential lower than that applied to the first portion of the second photoelectric conversion unit is applied to the second portion of the second photoelectric conversion unit, a potential higher than that applied to the first portion of the first photoelectric conversion unit is applied to the second portion of the first photoelectric conversion unit, and When a potential lower than that applied to the first portion of the first photoelectric conversion unit is applied to the second portion of the first photoelectric conversion unit, a potential higher than that applied to the first portion of the second photoelectric conversion unit is applied to the second portion of the second photoelectric conversion unit.

14. The photoelectric conversion method according to any one of claims 11 to 13, wherein, In at least two of the plurality of photoelectric conversion units, a potential lower than that applied to the first part is applied to the second part.

Images