Wavelength conversion light guide member and quantum sensor

Abstract

Provided is a wavelength conversion light guide member capable of improving light extraction efficiency.　A wavelength conversion light guide member 1 comprises: a wavelength conversion unit 8 that converts the wavelength of first wavelength light A and emits the light; and a light guide unit 9 that guides the first wavelength light A and second wavelength light B emitted by the wavelength conversion unit 8. The light guide unit 9 has a hole 4 that allows the first wavelength light A to pass therethrough and guides the second wavelength light B by reflecting the second wavelength light on an inner surface 4b.

Description

Wavelength Conversion Light Guide Member and Quantum Sensor

[0001] The present invention relates to a wavelength conversion light guide member and a quantum sensor using the wavelength conversion light guide member.

[0002] In recent years, quantum sensors have attracted attention as more sensitive sensors in in-vehicle fields such as electric vehicles and medical fields. As quantum sensors, sensors using materials such as diamond having a nitrogen-vacancy center (NV center) and silicon carbide having silicon vacancies are known.

[0003] As such a quantum sensor, Patent Document 1 below discloses a diamond magneto-optical sensor including a diamond having a color center with a quantum spin and a reflecting surface that is propagated through an optical system and reflects excitation light incident on the inside of the diamond. In Patent Document 1, the reflecting surface included in the diamond magneto-optical sensor reflects the emitted light emitted from the color center excited by the excitation light and condenses it in the direction of the optical system, and the condensing efficiency is enhanced. Further, in Patent Document 1, for example, it is described that the diamond is cut into a corner cube shape to form the above reflecting surface.

[0004] International Publication No. 2022 / 210695

[0005] However, in a quantum sensor such as that of Patent Document 1, the light extraction efficiency may not be sufficiently increased. Further, when a reflecting surface is formed by processing a diamond as in Patent Document 1, it may be difficult to increase productivity because the processing of the diamond takes time and cost.

[0006] An object of the present invention is to provide a wavelength conversion light guide member capable of increasing the light extraction efficiency and a quantum sensor using the wavelength conversion light guide member.

[0007] Each aspect of the wavelength conversion light guide member and the quantum sensor that solve the above problems will be described.

[0008] A wavelength conversion light guide member according to Embodiment 1 of the present invention comprises a wavelength conversion unit that converts and emits a first wavelength light, and a light guide unit that guides the first wavelength light and the second wavelength light emitted by the wavelength conversion unit, wherein the light guide unit has a hole that allows the first wavelength light to pass through and guides the second wavelength light by reflecting it on its inner surface. In the wavelength conversion light guide member according to Embodiment 1, of the second wavelength light that is converted and emitted by the wavelength conversion unit, not only the light that travels toward the opening side of the hole, but also the light that travels toward the inner surface side of the hole can be reflected on the inner surface of the hole and guided toward the opening side of the hole. Therefore, the second wavelength light can be efficiently extracted from the opening of the hole. Accordingly, the wavelength conversion light guide member according to Embodiment 1 can improve the efficiency of light extraction.

[0009] In the wavelength conversion light guide member according to embodiment 2, in embodiment 1, the wavelength conversion light guide member has a substrate portion and a main body portion provided on the substrate portion and having a through hole, and the main body portion is provided on the substrate portion so that the through hole of the main body portion constitutes the hole portion, and the wavelength conversion portion may be provided on the substrate portion and within the hole portion of the main body portion. In this case, the productivity of the wavelength conversion light guide member can be further increased.

[0010] In the wavelength conversion light guide member according to embodiment 3, the hole portion may have a tapered shape in embodiment 1 or embodiment 2. In this case, the light extraction efficiency in the wavelength conversion light guide member can be further improved.

[0011] In the wavelength conversion light guide member according to embodiment 4, in any one embodiment from embodiment 1 to embodiment 3, the maximum dimension of the hole in a plan view may decrease from the side where the wavelength conversion unit is provided toward the opening side of the hole. In this case, the light extraction efficiency of the wavelength conversion light guide member can be further increased.

[0012] In the wavelength conversion light guide member according to embodiment 5, in any one embodiment from embodiment 1 to embodiment 3, the maximum dimension of the hole in a plan view may increase from the side where the wavelength conversion unit is provided toward the opening side of the hole. In this case, the wavelength conversion light guide member can be made even smaller.

[0013] In the wavelength conversion light guide member according to embodiment 6, a reflective film may be provided on the inner surface of the hole in any one embodiment from embodiment 1 to embodiment 5. In this case, the reflective film can efficiently reflect the second wavelength light, further increasing the light extraction efficiency in the wavelength conversion light guide member.

[0014] In the wavelength conversion light guide member according to embodiment 7, in embodiment 6, the reflective film may contain at least one metal selected from the group consisting of Al, Ag, and Au. In this case, the reflective film can reflect the second wavelength light even more efficiently, and the light extraction efficiency in the wavelength conversion light guide member can be further improved.

[0015] In the wavelength conversion light guide member according to embodiment 8, the inside of the hole may be filled with resin in any one embodiment from embodiment 1 to embodiment 7. In this case, the light extraction efficiency of the wavelength conversion light guide member can be further increased.

[0016] In the wavelength conversion light guide member according to embodiment 9, it is preferable that the refractive index of the resin is greater than the refractive index of the material constituting the light guide portion in embodiment 8. In this case, the second wavelength light can be efficiently reflected at the interface between the resin and the inner surface of the hole, and the light extraction efficiency in the wavelength conversion light guide member can be further improved.

[0017] In the wavelength conversion light guide member according to embodiment 10, it is preferable that the wavelength conversion portion is made of a quantum sensor material provided on the substrate portion in any one embodiment from embodiment 2 to embodiment 9.

[0018] In the wavelength conversion light guide member according to embodiment 11, in embodiment 10, it is preferable that the quantum sensor material is at least one selected from the group consisting of diamond having nitrogen-vacancy centers, silicon carbide having silicon vacancies, and hexagonal boron nitride having boron vacancies.

[0019] In the wavelength conversion light guide member according to embodiment 12, a reflective film may be provided between the substrate portion and the quantum sensor material in embodiment 10 or embodiment 11. In this case, the manufacturing of the wavelength conversion light guide member does not involve complicated work, such as processing a diamond to form a reflective surface. Therefore, in this case, the productivity of the wavelength conversion light guide member can be further increased.

[0020] In the wavelength conversion light guide member according to embodiment 13, it is preferable that the substrate portion and the main body portion are made of glass in any one embodiment from embodiment 2 to embodiment 12. In this case, the productivity of the wavelength conversion light guide member can be further increased.

[0021] In the wavelength conversion light guide member according to embodiment 14, in any one embodiment from embodiment 2 to embodiment 13, the substrate portion is a support substrate made of glass, the main body portion is a glass member having the through hole, and the support substrate and the glass member may be joined by an adhesive. In this case, the productivity of the wavelength conversion light guide member can be further increased.

[0022] In the wavelength conversion light guide member according to embodiment 15, the glass member may have etching marks in embodiment 14. This makes it difficult for microcracks to form on the surface of the glass member, thus reducing the mechanical strength of the wavelength conversion light guide member.

[0023] In the wavelength conversion light guide member according to embodiment 16, in any one embodiment from embodiment 2 to embodiment 15, an optical fiber may be connected to the end face of the main body opposite to the side on which the wavelength conversion unit is provided.

[0024] A quantum sensor according to embodiment 17 of the present invention is characterized by comprising a light source that emits light of the first wavelength, a wavelength conversion light guide member according to any one embodiment from embodiment 1 to embodiment 16, and a light-receiving element that receives light of the second wavelength. Since the quantum sensor according to embodiment 17 is equipped with the wavelength conversion light guide member, the sensing sensitivity can be effectively increased.

[0025] According to the present invention, it is possible to provide a wavelength conversion light guide member and a quantum sensor using the wavelength conversion light guide member that can improve the efficiency of light extraction.

[0026] Figure 1 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a first embodiment of the present invention. Figure 2 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a second embodiment of the present invention. Figure 3 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a third embodiment of the present invention. Figure 4 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a fourth embodiment of the present invention. Figure 5 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a fifth embodiment of the present invention. Figure 6 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a modified example of the fifth embodiment of the present invention. Figure 7 is a schematic cross-sectional view showing a quantum sensor according to one embodiment of the present invention.

[0027] The embodiments are described below. However, the following embodiments are merely illustrative, and the present invention is not limited to these embodiments. In addition, in each drawing, components having substantially the same function may be referred to by the same reference numerals.

[0028] [Wavelength Conversion Light Guide Member] (First Embodiment) Figure 1 is a schematic cross-sectional view showing a wavelength conversion light guide member according to the first embodiment of the present invention.

[0029] As shown in Figure 1, the wavelength conversion light guide member 1 comprises a wavelength conversion section 8 and a light guide section 9. The wavelength conversion section 8 is the part that converts the wavelength of the first wavelength light A and emits it. The light guide section 9 is the part that guides the first wavelength light A and the second wavelength light B emitted by the wavelength conversion section 8. The light guide section 9 also has a hole 4. The hole 4 is provided to allow the first wavelength light A to pass through and to guide the second wavelength light B by reflecting it off its inner surface 4b.

[0030] More specifically, the wavelength conversion light guide member 1 of this embodiment is configured as follows. The wavelength conversion light guide member 1 has a substrate portion 2 and a main body portion 3. In this embodiment, the substrate portion 2 and the main body portion 3 are provided as separate components. However, in the present invention, the substrate portion 2 and the main body portion 3 may be provided integrally as a single component, but as will be explained in the section on the manufacturing method described later, it is preferable that the substrate portion 2 and the main body portion 3 are provided as separate components in order to make the wavelength conversion light guide member 1 easier to manufacture.

[0031] In this embodiment, the substrate portion 2 has a rectangular plate shape. However, the shape of the substrate portion 2 is not particularly limited, and may be, for example, a circular disc shape.

[0032] A main body portion 3 is provided on the main surface 2a of the substrate portion 2. The main body portion 3 has opposing first end faces 3a and second end faces 3b. In this embodiment, the main body portion 3 has a rectangular parallelepiped shape. However, the shape of the main body portion 3 is not particularly limited, and may be cylindrical, for example.

[0033] In the main body portion 3, a through hole 3A is provided extending from the first end face 3a to the second end face 3b. The second end face 3b of the main body portion 3 is in contact with the main surface 2a of the substrate portion 2. Therefore, on the side of the second end face 3b of the main body portion 3, the through hole 3A is blocked by the main surface 2a of the substrate portion 2. This constitutes the hole portion 4 of the wavelength conversion light guide member 1. The hole portion 4 is open on the side of the first end face 3a of the main body portion 3. Thus, in this embodiment, by providing the main body portion 3 on the substrate portion 2, the through hole 3A of the main body portion 3 constitutes the hole portion 4.

[0034] In this embodiment, the shape of the hole 4 is circular in plan view. However, the shape of the hole 4 is not particularly limited and may be rectangular, for example.

[0035] A quantum sensor material 6 is provided on the main surface 2a of the substrate portion 2. A reflective film 5A is provided between the substrate portion 2 and the quantum sensor material 6. The quantum sensor material 6 and the reflective film 5A are provided within the hole portion 4.

[0036] The quantum sensor material 6 is a component that converts the wavelength of first wavelength light A to second wavelength light B. The quantum sensor material 6 may also serve as a component that reflects the second wavelength light B. In this embodiment, the quantum sensor material 6 is diamond having nitrogen-vacancy centers (NV centers). However, the material of the quantum sensor material 6 is not particularly limited as long as it can convert the wavelength of first wavelength light A to second wavelength light B. Also, in this embodiment, the quantum sensor material 6 has a rectangular plate shape. However, the shape of the quantum sensor material 6 is not particularly limited and can be appropriately determined according to the material of the quantum sensor material 6. In this embodiment, the wavelength conversion unit 8 is composed of the quantum sensor material 6.

[0037] The reflective film 5A is a component that reflects the second wavelength light B, which has been wavelength-converted by the quantum sensor material 6. In this embodiment, the reflective film 5A is provided over the entire surface of the main surface 2a of the substrate portion 2. However, the reflective film 5A may be provided only in the portion where the quantum sensor material 6 is provided, or only in the portion where the quantum sensor material 6 is provided and its periphery. In addition, the reflective film 5A may not be provided at all.

[0038] In this embodiment, a reflective film 5B is also provided on the inner surface 3c of the main body 3. The reflective film 5B is a component that further reflects the second wavelength light B emitted after wavelength conversion by the wavelength conversion unit 8. In this embodiment, the reflective film 5B is provided over the entire inner surface 3c of the main body 3. However, the reflective film 5B may be provided on only a part of the inner surface 3c of the main body 3, but it is preferable that the reflective film 5B is provided over 80% or more of the inner surface 3c of the main body 3. Note that if resin is filled into the hole 4 as in the fifth embodiment described later, the reflective film 5B may not be provided.

[0039] In this embodiment, the second wavelength light B is reflected by the reflective film 5B inside the hole 4 of the main body 3 and guided to the first end face 3a side of the main body 3, that is, to the opening 4a side of the hole 4. Therefore, in this embodiment, the main body 3 and the reflective film 5B constitute the light guide portion 9.

[0040] In this embodiment, an optical fiber 7 is connected to the first end face 3a of the main body portion 3. The first end face 3a of the main body portion 3 is the end face on the side opposite to the side where the wavelength conversion portion 8 of the main body portion 3 is provided. In this embodiment, the first wavelength light A enters the hole portion 4 of the light guide portion 9 via the optical fiber 7. However, the wavelength conversion light guide member 1 may not be provided with the optical fiber 7, and the first wavelength light A emitted from the light source may directly enter the hole portion 4 of the light guide portion 9.

[0041] Hereinafter, referring to FIG. 1, an example of the optical paths of the first wavelength light A and the second wavelength light B in the wavelength conversion light guide member 1 of this embodiment will be described. In FIG. 1, only a part of the optical path of the second wavelength light B that is wavelength-converted and emitted by the wavelength conversion portion 8 is illustrated. Also, in FIG. 1, the second wavelength light B that is wavelength-converted and emitted at only one location (for example, the NV center) of the wavelength conversion light guide member 1 is illustrated by an arrow, but actually, it is assumed that the second wavelength light B that is wavelength-converted at a plurality of locations (for example, the NV center) is emitted. The same shall apply in FIG. 7.

[0042] In the wavelength conversion light guide member 1 of this embodiment, excitation light as the first wavelength light A emitted from a light source (not shown) enters from the end face 7a of the optical fiber 7. The first wavelength light A that enters from the end face 7a of the optical fiber 7 passes through the core 7A of the optical fiber 7, exits from the end face 7b of the optical fiber 7, and enters the hole portion 4 of the light guide portion 9.

[0043] The first wavelength light A that enters the hole portion 4 of the light guide portion 9 passes through the hole portion 4 of the light guide portion 9 and travels toward the wavelength conversion portion 8. The first wavelength light A that reaches the wavelength conversion portion 8 is wavelength-converted and emitted at the wavelength conversion portion 8. In this embodiment, the first wavelength light A is wavelength-converted by the quantum sensor material 6 and fluorescence is emitted as the second wavelength light B. At this time, the second wavelength light B that is wavelength-converted and emitted at the wavelength conversion portion 8 directly travels toward the light guide portion 9 or is reflected by the reflection film 5A and travels toward the light guide portion 9. The wavelength of the first wavelength light A can be, for example, 500 nm or more and 550 nm or less. Also, the wavelength of the second wavelength light B can be, for example, 600 nm or more and 700 nm or less.

[0044] Further, the second wavelength light B wavelength-converted and emitted by the wavelength conversion unit 8 passes through the hole 4 of the light guide unit 9 and travels toward the optical fiber 7 side or toward the inner surface 4b (inner side surface 3c of the main body unit 3) of the hole 4. In the present embodiment, since the reflection film 5B is provided on the inner surface 4b of the hole 4, the light traveling toward the inner surface 4b of the hole 4 is reflected by the reflection film 5B and is guided to the opening 4a side of the hole 4. The second wavelength light B guided to the opening 4a side of the hole 4 is emitted to the outside through the core 7A of the optical fiber 7.

[0045] Thus, in the wavelength conversion light guide member 1 of the present embodiment, not only the light traveling toward the opening 4a side of the hole 4 but also the light traveling toward the inner surface 4b side of the hole 4 among the second wavelength light B wavelength-converted and emitted by the wavelength conversion unit 8 can be guided to the opening 4a side of the hole 4, so that the second wavelength light B can be efficiently extracted from the opening 4a of the hole 4. Therefore, in the wavelength conversion light guide member 1 of the present embodiment, the light extraction efficiency can be increased.

[0046] Further, since the wavelength conversion light guide member 1 of the present embodiment is configured by disposing the quantum sensor material 6 in the hole 4 of the light guide unit 9, when manufacturing the wavelength conversion light guide member 1, for example, it does not involve complicated operations as in the case of processing diamond to form a reflecting surface. Therefore, the wavelength conversion light guide member 1 of the present embodiment is also excellent in productivity.

[0047] In the present embodiment, the hole 4 of the light guide unit 9 has a tapered shape. Specifically, the maximum dimension in the plan view of the hole 4 decreases from the side where the wavelength conversion unit 8 is provided toward the opening 4a side of the hole 4. In the present embodiment, the inner diameter of the hole 4 decreases from the side where the wavelength conversion unit 8 is provided toward the opening 4a side of the hole 4. When the hole 4 of the light guide unit 9 has such a structure, the light extraction efficiency in the wavelength conversion light guide member 1 can be further improved.

[0048] In this embodiment, the core 7A of the optical fiber 7 and the opening 4a of the hole 4 are arranged to overlap in a plan view. In a plan view, it is sufficient that the core 7A of the optical fiber 7 and the opening 4a of the hole 4 overlap at least partially. In a plan view, the core 7A of the optical fiber 7 and the opening 4a of the hole 4 may be arranged to completely overlap, the core 7A of the optical fiber 7 may be enclosed within the opening 4a of the hole 4, or the opening 4a of the hole 4 may be enclosed within the core 7A of the optical fiber 7. However, in this embodiment, it is preferable that the core 7A of the optical fiber 7 is enclosed within the opening 4a of the hole 4 in a plan view.

[0049] The following describes in detail each component that makes up the wavelength conversion light guide member 1.

[0050] Substrate portion; For example, glass, silicon, ceramics, etc. can be used as the material for the substrate portion 2. Among these, glass is preferred as the material for the substrate portion 2. Examples of glass that can be used include borosilicate glass, aluminosilicate glass, soda-lime glass, alkali-free glass, LAS-based crystallized glass, or quartz glass. Furthermore, if the material for the substrate portion 2 is glass, the glass may have etching marks. In this case, microcracks are less likely to form on the surface of the substrate portion 2, so a decrease in mechanical strength in the wavelength conversion light guide member 1 is less likely to occur.

[0051] The thickness of the substrate portion 2 can be, for example, 0.1 mm or more and 2.0 mm or less. The area of ​​the main surface 2a of the substrate portion 2 is, for example, 1 mm². ２ Above 20mm ２ The following is possible:

[0052] As the reflective film 5A provided on the substrate portion 2, for example, a metal film or a dielectric multilayer film can be used. Examples of materials for the metal film include Al, Ag, or Au. As the dielectric multilayer film, a conventionally known dielectric multilayer film can be used, which includes a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index. Among these, the material of the reflective film 5A is preferably a dielectric multilayer film.

[0053] The thickness of the reflective film 5A is preferably 1 μm or more, more preferably 2 μm or more, preferably 6 μm or less, and more preferably 5 μm or less.

[0054] Main body; For example, glass, silicon, ceramics, etc. can be used as the material for the main body 3. In particular, it is preferable that the material of the main body 3 be a glass member. Examples of glass used as the glass member include borosilicate glass, aluminosilicate glass, soda-lime glass, alkali-free glass, LAS-based crystallized glass, or quartz glass. Furthermore, if the main body 3 is a glass member, the glass member may have etching marks. In this case, microcracks are less likely to form on the surface of the glass member, so a decrease in mechanical strength is less likely to occur. As for the material of the main body 3, it is preferable to use the same material as the substrate 2 from the viewpoint of matching the thermal expansion coefficient of the substrate 2, but the material of the main body 3 and the material of the substrate 2 may be different.

[0055] The thickness of the main body portion 3 (distance between the first end face 3a and the second end face 3b) can be, for example, 0.1 mm or more and 1.0 mm or less. The area of ​​the first end face 3a and the second end face 3b of the main body portion 3 is 1 mm² each. ２ Above 20mm ２ The following is possible: The areas of the first end face 3a and the second end face 3b of the main body portion 3 are preferably the same as the area of ​​the main surface 2a of the substrate portion 2, but they may be different from the area of ​​the main surface 2a of the substrate portion 2.

[0056] As the reflective film 5B provided on the inner surface 4b of the hole 4, for example, a metal film or a dielectric multilayer film can be used. Examples of materials for the metal film include Al, Ag, or Au. As the dielectric multilayer film, conventionally known dielectric multilayer films can be used, which include a high refractive index film with a relatively high refractive index and a low refractive index film with a relatively low refractive index. In particular, the material of the reflective film 5B is preferably at least one metal selected from the group consisting of Al, Ag, and Au. The material of the reflective film 5B and the material of the reflective film 5A may be different.

[0057] The thickness of the reflective film 5B is preferably 0.1 μm or more, more preferably 0.12 μm or more, preferably 2.2 μm or less, and more preferably 2.0 μm or less.

[0058] Quantum sensor material; The material of the quantum sensor material 6 is not particularly limited, as long as it can wavelength-convert light of a first wavelength A to light of a second wavelength B. As the quantum sensor material 6, diamond having nitrogen-vacancy centers, silicon carbide having silicon vacancies, or hexagonal boron nitride having boron vacancies can be used. Among these, the quantum sensor material 6 is preferably diamond having nitrogen-vacancy centers. In this case, when the wavelength-converting light guide member 1 is used in the quantum sensor, the sensitivity of the quantum sensor can be further increased.

[0059] The following describes in detail a manufacturing method for an example of the wavelength conversion light guide member 1.

[0060] Manufacturing method; In the manufacturing method of the wavelength conversion light guide member 1 of this embodiment, first, a support substrate constituting the substrate portion 2 is prepared. The material of the substrate portion 2 described above can be used as the material of the support substrate.

[0061] Next, a reflective film is formed on the support substrate. The method for forming the reflective film is not particularly limited, but examples include sputtering or vapor deposition. In this case, it is preferable to form the reflective film over the entire surface of the support substrate, but it is not necessary to form the reflective film on the portion that is joined to the main body component, which will be described later.

[0062] Next, the main body components that make up the main body 3 are prepared. It is preferable to use glass members or the like as the main body components, and the materials for the main body 3 described above can be used.

[0063] Next, a through-hole 3A is formed in the main body component. The method for forming the through-hole is not particularly limited, but examples include etching after laser modification, laser processing, or machining. The etching conditions, such as the etching solution, solution temperature, and processing time, are adjusted according to the design value of the taper angle.

[0064] Next, the support substrate and the main body components are joined together with an adhesive to form the substrate portion 2 and the main body portion 3. For example, UV-curing resin or thermosetting resin can be used as the adhesive. The method of joining the support substrate and the main body components is not particularly limited.

[0065] Next, the quantum sensor material 6 is mounted on the main surface 2a (reflective film 5A) of the substrate portion 2. The method of joining the reflective film 5A and the quantum sensor material 6 is not particularly limited, and for example, they can be joined using the adhesive described above. Also, if necessary, the optical fiber 7 is joined to the first end face 3a of the main body portion 3. The method of joining the first end face 3a of the main body portion 3 and the end face 7b of the optical fiber 7 is not particularly limited, and for example, they can be joined using the adhesive described above. An anti-reflective film may be provided on the end face 7b of the optical fiber 7. In this way, the wavelength conversion light guide member 1 can be obtained.

[0066] (Second and Third Embodiments) Figure 2 is a schematic cross-sectional view showing a wavelength conversion light guide member according to the second embodiment of the present invention. In Figure 2, only a portion of the optical path of the second wavelength light B emitted after wavelength conversion by the wavelength conversion unit 28 is shown. In practice, the second wavelength light B is emitted as described in the first embodiment. The same applies to Figure 3.

[0067] As shown in Figure 2, in the wavelength conversion light guide member 21, the hole 24 of the light guide portion 29 has a tapered shape opposite to that of the first embodiment (hereinafter referred to as reverse tapered shape). More specifically, the maximum dimension of the hole 24 in a plan view increases from the side where the wavelength conversion portion 28 is provided toward the opening 24a side of the hole 24. In this embodiment, the inner diameter of the hole 24 increases from the side where the wavelength conversion portion 28 is provided toward the opening 24a side of the hole 24.

[0068] In the second embodiment as well, in a plan view, it is sufficient that the core of the optical fiber (not shown) and the opening 24a of the hole 24 overlap at least partially. In a plan view, the core of the optical fiber and the opening 24a of the hole 24 may completely overlap, the core of the optical fiber may be enclosed within the opening 24a of the hole 24, or the opening 24a of the hole 24 may be enclosed within the core of the optical fiber. However, in the second embodiment, it is preferable that, in a plan view, the core of the optical fiber is enclosed within the opening 24a of the hole 24.

[0069] Other aspects are the same as in the first embodiment.

[0070] Figure 3 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a third embodiment of the present invention.

[0071] As shown in Figure 3, in the wavelength conversion light guide member 31, the hole 34 of the light guide portion 39 has a straight shape. More specifically, the maximum dimension of the hole 34 in a plan view is substantially constant from the side where the wavelength conversion portion 38 is provided to the opening 34a side of the hole 34. In this embodiment, the inner diameter of the hole 34 is substantially constant from the side where the wavelength conversion portion 38 is provided to the opening 34a side of the hole 34.

[0072] In the third embodiment as well, in a plan view, it is sufficient that the core of the optical fiber (not shown) and the opening 34a of the hole 34 overlap at least partially. In a plan view, the core of the optical fiber and the opening 34a of the hole 34 may completely overlap, the core of the optical fiber may be enclosed within the opening 34a of the hole 34, or the opening 34a of the hole 34 may be enclosed within the core of the optical fiber. However, in the third embodiment, it is preferable that, in a plan view, the core of the optical fiber is enclosed within the opening 34a of the hole 34.

[0073] Other aspects are the same as in the second embodiment.

[0074] In the wavelength conversion light guide members 21 and 31 of the second and third embodiments, not only the light that travels toward the openings 24a and 34a of the holes 24 and 34, but also the light that travels toward the inner surfaces 24b and 34b of the holes 24 and 34 can be guided toward the openings 24a and 34a of the holes 24 and 34, so that the second wavelength light B can be efficiently extracted from the openings 24a and 34a of the holes 24 and 34. Therefore, the light extraction efficiency can be increased in the wavelength conversion light guide members 21 and 31 of the second and third embodiments as well.

[0075] Furthermore, the wavelength conversion light guide members 21 and 31 of the second and third embodiments are also constructed by arranging quantum sensor materials 26 and 36 in the holes 24 and 34 of the light guide sections 29 and 39. Therefore, the manufacturing of the wavelength conversion light guide members 21 and 31 does not involve complicated work, such as processing a diamond to form a reflective surface. Accordingly, the wavelength conversion light guide members 21 and 31 of this embodiment are also excellent in terms of productivity.

[0076] As shown in the first to third embodiments, the shape of the hole in the light guide portion may be tapered, inversely tapered, or straight. The size of the quantum sensor material can be appropriately designed according to the shape of the hole. For example, as in the second embodiment, if the hole 24 has an inversely tapered shape, the quantum sensor material 26 can be made even smaller. However, in the present invention, the shape of the hole in the light guide portion is not particularly limited and may be, for example, drum-shaped.

[0077] (Fourth Embodiment) Figure 4 is a schematic cross-sectional view showing a wavelength conversion light guide member according to the fourth embodiment of the present invention.

[0078] As shown in Figure 4, in the wavelength conversion light guide member 41, resin 40 is filled inside the holes 44 of the light guide portion 49. The resin 40 is not particularly limited, and for example, a UV-curing resin can be used.

[0079] Other aspects are the same as in the first embodiment.

[0080] In the wavelength conversion light guide member 41 of the fourth embodiment, the structure is the same as the first embodiment except that the inside of the hole 44 of the light guide portion 49 is filled with resin 40. Therefore, the light extraction efficiency can be increased, and productivity can be improved.

[0081] (Fifth Embodiment) Figure 5 is a schematic cross-sectional view showing a wavelength conversion light guide member according to the fifth embodiment of the present invention.

[0082] As shown in Figure 5, in the wavelength conversion light guide member 51, the hole 54 of the light guide portion 59 has the same reverse tapered shape as in the second embodiment. Also, the inside of the hole 54 of the light guide portion 59 is filled with resin 50. The refractive index of the resin 50 is greater than that of the material constituting the light guide portion 59. In this embodiment, the refractive index of the resin 50 is greater than that of the material constituting the main body portion 53. Furthermore, in the wavelength conversion light guide member 51, no reflective film is provided on the main surface 52a of the substrate portion 52 and on the inner surface 53c of the main body portion 53. In this embodiment, the second wavelength light B can be reflected at the interface between the resin 50 and the inner surface 53c of the main body portion 53 (inner surface 54b of the hole 54).

[0083] The difference between the refractive index of the resin 50 and the material constituting the main body 53 at a wavelength of 600 nm is preferably 0.1 or more, more preferably 0.2 or more. In this case, the light extraction efficiency of the wavelength conversion light guide member 51 can be further improved.

[0084] It is preferable to use a UV-curing resin for the resin 50. Furthermore, it is preferable to use borosilicate glass as the material constituting the main body 53.

[0085] Other aspects are the same as in the second embodiment.

[0086] In the wavelength conversion light guide member 51 of the fifth embodiment, the second wavelength light B can be reflected at the interface between the resin 50 and the inner surface 53c of the main body 53 (inner surface 54b of the hole 54), so the light extraction efficiency can be increased, similar to the wavelength conversion light guide member 21 of the second embodiment.

[0087] The wavelength conversion light guide member 51 of the fifth embodiment is also constructed by arranging the quantum sensor material 56 in the hole 54 of the light guide portion 59. Therefore, when manufacturing the wavelength conversion light guide member 51, complicated work is not required, such as when processing a diamond to form a reflective surface. Accordingly, the wavelength conversion light guide member 51 of this embodiment is also excellent in terms of productivity.

[0088] Figure 6 is a schematic cross-sectional view showing a wavelength conversion light guide member according to a modified example of the fifth embodiment of the present invention.

[0089] As shown in Figure 6, the wavelength conversion light guide member 51A, in the fifth embodiment, the hole 54 of the light guide portion 59 may have a straight shape. In this case as well, the second wavelength light B can be reflected at the interface between the resin 50 and the inner surface 53c of the main body portion 53 (inner surface 54b of the hole 54), so the light extraction efficiency can be increased, similar to the wavelength conversion light guide member 51 of the fifth embodiment.

[0090] Furthermore, since the wavelength conversion light guide member 51A is also constructed by arranging the quantum sensor material 56 within the hole 54 of the light guide portion 59, the manufacturing of the wavelength conversion light guide member 51A does not involve complicated work, such as processing a diamond to form a reflective surface. Therefore, the wavelength conversion light guide member 51A of this modified example is also excellent in terms of productivity.

[0091] [Quantum Sensor] Figure 7 is a schematic cross-sectional view showing a quantum sensor according to one embodiment of the present invention.

[0092] The quantum sensor 61 comprises a light source and a light-receiving element 62, and a wavelength conversion light guide member 1. The light source and light-receiving element 62 also functions as a light source that emits a first wavelength light A and a light-receiving element that receives a second wavelength light B. The wavelength conversion light guide member 1 is the same as the wavelength conversion light guide member 1 described in the first embodiment.

[0093] In the quantum sensor 61, excitation light as first wavelength light A emitted from the light source of the light source and the photodetector element 62 is incident from the end face 7a of the optical fiber 7. The first wavelength light A incident from the end face 7a of the optical fiber 7 passes through the core 7A of the optical fiber 7, exits from the end face 7b of the optical fiber 7, and is incident on the hole 4 of the light guide portion 9.

[0094] The first wavelength light A that enters the hole 4 of the light guide 9 passes through the hole 4 of the light guide 9 and proceeds toward the wavelength conversion 8. The first wavelength light A that reaches the wavelength conversion 8 is wavelength converted and emitted by the wavelength conversion 8. In this embodiment, the first wavelength light A is wavelength converted by the quantum sensor material 6 and fluorescence is emitted as the second wavelength light B. At this time, the second wavelength light B emitted after wavelength conversion in the wavelength conversion 8 either proceeds directly toward the light guide 9 or is reflected by the reflective film 5A and proceeds toward the light guide 9.

[0095] Furthermore, the second wavelength light B emitted after wavelength conversion in the wavelength conversion unit 8 passes through the hole 4 of the light guide unit 9 and either proceeds toward the optical fiber 7 side or toward the inner surface 4b of the hole 4 (inner surface 3c of the main body 3). In this embodiment, since a reflective film 5B is provided on the inner surface 4b of the hole 4, the light that proceeds toward the inner surface 4b of the hole 4 is reflected by the reflective film 5B and guided toward the opening 4a of the hole 4.

[0096] The second wavelength light B emitted from the opening 4a of the hole 4 now enters the optical fiber 7 from the end face 7b. The second wavelength light B that entered from the end face 7b of the optical fiber 7 passes through the core 7A of the optical fiber 7, exits from the end face 7a of the optical fiber 7, and reaches the light-receiving element of the light source and light-receiving element 62. In this way, fluorescence as the second wavelength light B is detected in the light source and the light-receiving element of the light-receiving element 62.

[0097] The quantum sensor 61 of this embodiment is equipped with a wavelength conversion light guide member 1 that has excellent light extraction efficiency, so the sensing sensitivity can be effectively increased.

[0098] 1, 21, 31, 41, 51, 51A...Wavelength conversion light guide member 2, 52...Substrate part 2a, 52a...Main surface 3, 23, 53...Main body part 3A...Through hole 3a, 23a, 33a...First end face 3b, 23b...Second end face 3c, 23c, 53c...Inner surface 3A...Through hole 4, 24, 34, 44, 54...Hole part 4a, 24a, 34a...Opening 4b, 24b, 34b, 54b...Inner surface 5A, 5B...Reflective film 6, 26, 36, 56...Quantum sensor material 7...Optical fiber 7A...Core 7a, 7b...End face 8, 28, 38, 48...Wavelength conversion part 9, 29, 39, 49, 59...Light guide part 40, 50...Resin 61...Quantum sensor 62...Light source and light receiving element A...First wavelength light B...Second wavelength light

Claims

1. A wavelength conversion light guide member comprising: a wavelength conversion unit that converts and emits a first wavelength light; and a light guide unit that guides the first wavelength light and the second wavelength light emitted by the wavelength conversion unit, wherein the light guide unit has a hole that allows the first wavelength light to pass through and guides the second wavelength light by reflecting it on its inner surface.

2. The wavelength conversion light guide member according to claim 1, comprising: a substrate portion; a main body portion provided on the substrate portion and having a through hole, wherein the main body portion is provided on the substrate portion, the through hole of the main body portion constitutes the hole portion, and the wavelength conversion portion is provided on the substrate portion and within the hole portion of the main body portion.

3. The wavelength conversion light guide member according to claim 2, wherein the hole portion has a tapered shape.

4. The wavelength conversion light guide member according to claim 3, wherein the maximum dimension of the hole in a plan view decreases as you move from the side where the wavelength conversion unit is provided toward the opening side of the hole.

5. The wavelength conversion light guide member according to claim 3, wherein the maximum dimension of the hole in a plan view increases from the side where the wavelength conversion unit is provided toward the opening side of the hole.

6. The wavelength conversion light guide member according to any one of claims 1 to 5, wherein a reflective film is provided on the inner surface of the hole.

7. The wavelength conversion light guide member according to claim 6, wherein the reflective film comprises at least one metal selected from the group consisting of Al, Ag, and Au.

8. The wavelength conversion light guide member according to any one of claims 1 to 5, wherein the inside of the hole is filled with resin.

9. The wavelength conversion light guide member according to claim 8, wherein the refractive index of the resin is greater than the refractive index of the material constituting the light guide portion.

10. The wavelength conversion light guide member according to any one of claims 2 to 5, wherein the wavelength conversion unit is made of a quantum sensor material provided on the substrate unit.

11. The wavelength conversion light guide member according to claim 10, wherein the quantum sensor material is at least one selected from the group consisting of diamond having nitrogen-vacancy centers, silicon carbide having silicon vacancies, and hexagonal boron nitride having boron vacancies.

12. The wavelength conversion light guide member according to claim 10, wherein a reflective film is provided between the substrate portion and the quantum sensor material.

13. The wavelength conversion light guide member according to any one of claims 2 to 5, wherein the substrate portion and the main body portion are made of glass.

14. The wavelength conversion light guide member according to claim 13, wherein the substrate portion is a support substrate made of glass, the main body portion is a glass member having the through hole, and the support substrate and the glass member are joined together by an adhesive.

15. The wavelength conversion light guide member according to claim 14, wherein the glass member has etching marks.

16. The wavelength conversion light guide member according to any one of claims 2 to 5, wherein an optical fiber is connected to the end face of the main body opposite to the side on which the wavelength conversion unit is provided.

17. A quantum sensor comprising: a light source that emits light of the first wavelength; a wavelength conversion light guide member according to any one of claims 1 to 5; and a light-receiving element that receives light of the second wavelength.

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