Optical measurement head, endoscope, method for manufacturing optical measurement head, and optical measurement method

Abstract

The present invention measures a plurality of physicochemical quantities at the same or extremely close positions. This optical measurement head (20) comprises: a substrate (S) having a color center-containing layer (Ly) that contains a color center for measuring the state of an object (OB); and a light input / output unit (21) that faces or is in contact with the substrate, emits excitation light (L1), and receives fluorescence (L2). The substrate is divided into a plurality of regions differing from each other in at least one among the depth of the color center-containing layer from the surface of the substrate and a surface modification material for modifying the surface of the substrate.

Description

Optical measurement head, endoscope, method for manufacturing an optical measurement head, and optical measurement method

[0001] The present invention relates to an optical measurement head, an endoscope, a method for manufacturing an optical measurement head, and an optical measurement method.

[0002] Techniques for performing physicochemical measurements using NV centers are known (see Non-Patent Documents 1-4). Non-Patent Document 1 discloses a technique for measuring pH using NV centers in diamond. Non-Patent Documents 2-3 disclose a technique for measuring magnetic fields using NV centers in diamond.

[0003] T. Fujisaku et al., pH Nanosensor Using Electronic Spins in Diamond, ACS Nano 2019, 13, 10, 11726-11732Y. Masuyama et al., Sensors 2021, 21, 3, 977S. M. Blakley et al., Room-temperature magnetic gradiometry with fiber-coupled nitrogen-vacancy centers in diamond. Optics Letters Vol. 40, Issue 16, pp. 3727-3730 (2015)A. Kuwahata et al., Magnetometer with nitrogen-vacancy center in a bulk diamond for detecting magnetic nanoparticles in biomedical applications. Scientific Reports, (2020) 10:2483

[0004] However, the conventional techniques described above did not anticipate the measurement of multiple physicochemical quantities at the same or very close locations.

[0005] One aspect of the present invention aims to enable the measurement of multiple physicochemical quantities at the same or very close locations.

[0006] To solve the above problems, an optical measuring head according to one aspect of the present invention comprises a substrate having a color center-containing layer containing color centers for measuring the state of an object, and an optical input / output section facing or in contact with the substrate, which emits excitation light to excite the color centers and receives fluorescence from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the surface modification material modifying the surface of the substrate is different.

[0007] To solve the above problems, an optical measurement method according to one aspect of the present invention is an optical measurement method for optically measuring the state of an object, comprising: an incidence step of incidentally injecting excitation light into a substrate having a color center-containing layer containing color centers, and an emission step of causing fluorescence to be emitted from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the modifying material modifying the surface of the substrate differs.

[0008] According to one aspect of the present invention, multiple physicochemical quantities can be measured at the same or very close locations.

[0009] This is a block diagram showing an example of an optical measurement system according to Embodiment 1 of the present invention. This is a perspective view showing an example of an optical measurement head according to Embodiment 1 of the present invention. This is a schematic diagram showing the energy levels of an NV center. This is a timing chart showing an example of the timing of excitation light and high frequency applied to the optical measurement head. This is a flow diagram showing an example of a method for manufacturing an optical measurement head according to Embodiment 1 of the present invention. This is a schematic diagram showing an example of an optical measurement head under manufacture. This is a perspective view showing an example of an endoscope according to Embodiment 2 of the present invention. This is a graph showing an example of the measurement results of physicochemical quantities.

[0010] [Embodiment 1] An embodiment of the present invention will be described in detail below. Figure 1 is a block diagram showing an example of an optical measurement system 1 according to Embodiment 1 of the present invention. As shown in Figure 1, the optical measurement system 1 has an optical measurement head 20. The optical measurement head 20 has a substrate on which a color center is formed, as will be described later.

[0011] The optical measurement system 1 includes a light source 11, optical switches 12(1) to 12(n), dichroic mirrors 13(1) to 13(n), a pulse generator 14, an optical measurement head 20, filters 31(1) to 31(n), photodetectors 32(1) to 32(n), counters 33(1) to 33(n), and a control unit 34.

[0012] The light source 11 emits excitation light L1 to excite the color center of the optical measurement head 20. The excitation light emitted from the light source 11 is divided into n segments and passes through optical switches 12(1) to 12(n), dichroic mirrors 13(1) to 13(n), and optical fibers F1 to Fn before being incident on regions A1 to An of the optical measurement head 20. The optical switches 12(1) to 12(n) are switched ON and OFF by the pulse generator 14, converting the light from the light source 11 into pulsed light.

[0013] As a result, fluorescence L2 is emitted from the color centers of regions A1 to An of the optical measurement head 20. This fluorescence L2 passes through optical fibers F1 to Fn, is reflected by dichroic mirrors 13(1) to 13(n), passes through filters 31(1) to 31(n), and is detected by photodetectors 32(1) to 32(n). Filters 31(1) to 31(n) are wavelength-selective filters for removing excitation light contained in the light from the optical measurement head 20.

[0014] These detection results are accumulated by counters 33(1) to 33(n) and input to the control unit 34, where the measurement values ​​for each region A1 to An of the optical measurement head 20 are calculated.

[0015] The pulsed high-frequency waves generated by the high-frequency oscillator 41, high-frequency switch 42, and amplifier 43 are applied to the optical measurement head 20. As will be described later, the optical measurement head 20 has a high-frequency field radiating member 22, and the high-frequency electric field radiated from this high-frequency field radiating member 22 is applied to the color center.

[0016] Figure 2 is a perspective view showing an example of an optical measurement head 20. The optical measurement head 20 has a substrate S.

[0017] The substrate S has a color center-containing layer Ly containing color centers for measuring the state of the object OB. The substrate S is made of, for example, diamond. The color centers are, for example, nitrogen-vacancy centers (hereinafter also referred to as NV centers). In the following explanation, NV centers in diamond will be used as an example, but silicon vacancies in SiC may also be used as color centers.

[0018] The substrate S is divided into multiple regions A1 to An (here, A1 to A4, i.e., n=4. Hereafter, "n=4" will be used as an example). The multiple regions A1 to A4 differ in at least one of the following: the depth d1 to d4 of the color center-containing layer Ly from the surface of the substrate S, and the modifying material that modifies the surface of the substrate S. The depth d of the color center-containing layer Ly from the surface of the substrate S corresponds to the distance between the surface of the substrate S and the area in the color center-containing layer Ly with the highest density of color centers. This makes it easy to measure different physicochemical quantities in the multiple regions A1 to A4. The multiple regions A1 to A4 have first and second regions (e.g., regions A1 and A2) for measuring at least two selected from temperature, magnetic field, pH, ion concentration, and radicals, respectively. The details of this will be described later.

[0019] Furthermore, the substrate S may have multiple regions A1 to A4 in which at least one of the depth d of the color center-containing layer Ly and the chemical modification material M that chemically modifies the surface of the substrate S is different, as well as multiple regions in which the depth d of the color center-containing layer Ly and the chemical modification material are the same.

[0020] The substrate S preferably includes a light-blocking member SP disposed between a plurality of regions A1 to A4. By disposing a material SP that does not transmit light between the regions A1 to A4, it is possible to prevent the mixing of the excitation light L1 and the fluorescence L2 between the regions A1 to A4 and improve the measurement accuracy. As an example of the light-blocking member SP, a metal material can be cited.

[0021] One end of each of the optical fibers F1 to F4 is optically connected to the regions A1 to A4. This connection can be performed, for example, by an optical adhesive. The other ends of the optical fibers F1 to F4 are connected to a light source 11 and photodetectors 32(1) to 32(4). The optical fibers F1 to F4 function as a light input / output unit 21 that emits the excitation light L1 for exciting the color center and receives the fluorescence L2 from the color center excited by the excitation light L1.

[0022] Here, the light input / output unit 21 (optical fibers F1 to F4) is in contact with the substrate S. On the other hand, the light input / output unit 21 may be opposed to the substrate as, for example, an objective lens.

[0023] The optical measurement head 20 has a high-frequency electric field radiation member 22 for applying a high-frequency electric field to the color center. The high-frequency electric field radiation member 22 is, for example, a loop antenna, and is disposed near the tips of the optical fibers F1 to F4, and applies the microwave supplied from the high-frequency oscillator 41 to the color center (color center-containing layer Ly) near the tips of the optical fibers F1 to F4 via, for example, a coaxial line LC. Here, the high-frequency electric field radiation member 22 is installed on all of the optical fibers F1 to F4, but there may be optical fibers F1 to F4 on which the high-frequency electric field radiation member 22 is not installed. That is, the high-frequency electric field radiation member 22 is appropriately arranged according to the necessity of measurement (for example, measurement of a magnetic field).

[0024] For example, when measuring pH and ion concentration, it is preferable that the depth d of the color center-containing layer Ly be within about 1 μm (for example, about 50 nm) from the surface on the object OB side. By bringing the object OB and the color center-containing layer Ly close to each other, it becomes easy to measure, for example, the pH of the object OB.

[0025] The materials used to chemically modify regions A1 to A4 of the substrate S (chemical modification materials) are as follows: (1) When measuring temperature, the chemical modification material is a hydrophilic polymer. This is to prevent contamination of region Ai. Examples of hydrophilic polymers include PEG (polyethylene glycol) and HPG (hyper-branched polyglycerol). (2) When measuring magnetic fields, the chemical modification material is a hydrophilic polymer, for example, HPG. (3) When measuring pH, the chemical modification material is a material containing a functional group that causes proton dissociation depending on the pH of the object being measured, for example, a carboxyl group or a material containing a cysteine ​​group, for example, polycysteine. (4) When measuring ion concentration, the chemical modification material is, for example, anionic polymers (for example, polyacrylic acid), cationic polymers (for example, polyimide), proteins, peptides, crown ethers, chelating agents, ionophores, and derivatives thereof. The chemically modified material may also contain other polymers. (5) When measuring radicals, the chemically modified material is a material that is less likely to cause chemical reactions and nonspecific molecular adsorption by radicals. Examples of such chemically modified materials include alkyl groups, phenyl groups, hydroxyl groups (-OH), ketone groups (C=O), and amide groups (-CONH). ２ Examples of materials having an ester group (-COOR) or an electrically neutral functional group include PEG, polylactic acid (PLA), polycaprolactone (PCL), and derivatives thereof. This chemically modified material may also include other polymers having electrically neutral properties.

[0026] As an example, the depths d1 to d4 of the color center-containing layer Ly and at least one of the chemical modification materials M1 to M4 are made different in each of the regions A1 to A4, as follows. This makes it possible to preferably measure different measurement targets in each of the regions A1 to A4.

[0027] (1) Region A1 (Measurement target: Temperature) Chemical modification material M1: Hydrophilic polymer (e.g., PEG, HPG) (2) Region A2 (Measurement target: Magnetic field) Chemical modification material M2: Hydrophilic polymer (e.g., HPG) In the measurement of temperature and magnetic field, a wide range of the depth d of the color center-containing layer Ly is applicable, and in the formation of the color center, the depth d does not have to be specified.

[0028] (3) Region A3 (Measurement target: pH) Chemical modification material M3: A molecule in which the degree of proton dissociation at the residue end changes according to the ambient pH (e.g., a material containing a carboxyl group or a cysteine group) Depth d3 of the color center-containing layer Ly: A wide range is applicable (preferably 5 to 20 nm) (4) Region A4 (Measurement target: Radical) Chemical modification material M4: A material in which chemical reactions and non-specific molecular adsorption are unlikely to occur by radicals (e.g., PEG, PLA, PCL) Depth d4 of the color center-containing layer Ly: A wide range is applicable (preferably 5 to 20 nm)

[0029] Instead of, or in addition to, chemically modifying the surface of the substrate S, a predetermined functional material may be attached to the surface of the substrate S. For example, when measuring the pressure of the object OB, it is conceivable to attach a piezoelectric material (as an example, PZT, AlN, ZnO) to the surface of the substrate S. The piezoelectric material converts the pressure of the object OB into electric charges and measures the change in the coherence time due to the charge noise. As a result, the pressure can be indirectly measured.

[0030] FIG. 3 is a schematic diagram showing the energy levels of the NV center. As shown in FIG. 3, the NV center has a ground state ３ A ２ and an excited state ３ E. The ground state ３ A ２ is divided into two magnetic sublevels ms = 0, ms = ±1. The NV center is excited by excitation light L1 (wavelength: 532 nm) from the ground state ３ A ２ (ms = 0, ms = ±1) to the excited state ３ E (paths T11, T12). The NV center emits fluorescence L2 (wavelength: 637 nm) and is in the excited state３ From E to ground state ３ A ２ Transition to (path T2). Note that this is the original ground state. ３ A ２ The intensity of fluorescence L2 differs depending on whether the magnetic sub-level is ms = 0 or ms = ±1. Excited state ３ From E to ground state ３ A ２ The transition to this state can also be via a metastable state Sm, in which case it is a non-radiative transition in which no fluorescence is emitted.

[0031] By applying microwaves to the NV center, the intensity of fluorescence L2 decreases at frequencies corresponding to the energy difference between magnetic sub-levels ms=0 and ms=±1 (photodetected magnetic resonance). Since this resonance frequency depends on, for example, temperature and magnetic field, temperature and magnetic field can be measured. Furthermore, because the resonance frequencies of temperature and magnetic field shift in different directions, temperature and magnetic field can be measured simultaneously using excitation light L1 and fluorescence L2.

[0032] Figure 4 is a timing chart showing an example of the timing of the excitation light and high-frequency applied to the optical measurement head 20. As shown in Figure 4, there are several patterns SE1 to SE4 for the irradiation timing of the excitation light and high-frequency to the optical measurement head 20.

[0033] A. Measurement of resonance frequency by photodetection magnetic resonance When measuring resonance frequency by photodetection magnetic resonance, there are two methods: continuous measurement (pattern SE1) and pulse measurement (pattern SE2).

[0034] In the case of continuous measurement (pattern SE1), excitation light and high-frequency light are irradiated simultaneously, and fluorescence from the color center is detected by the photodetector 32. Here, the irradiation of excitation light and high-frequency light, and the detection of fluorescence are repeated while changing the frequency of the high-frequency light. In this case, the optical switch 12, pulse generator 14, and high-frequency switch 42 of the optical measurement system 1 are not required.

[0035] In the case of pulse measurement (pattern SE2), the color center is initialized by irradiating it with pulsed excitation light, then microwaves are irradiated, and then pulsed excitation light is irradiated to detect fluorescence from the color center using the photodetector 32.

[0036] B. Coherence time T １ , T ２ The measured coherence time (energy relaxation time) T is used. １ When using this method, the high frequency and excitation light are irradiated in pattern SE3-1 or SE3-2. The coherence time T is affected by electronic noise. １ Since it changes, we measure it. Measurable physical quantities include, for example, pH, radicals, and electric charge.

[0037] Coherence time (energy relaxation time) T ２ When using this method, the high-frequency and excitation light are irradiated using pattern SE4. The coherence time changes due to magnetic noise, and this is measured. One physical quantity that can be measured is, for example, spin noise.

[0038] Figure 5 is a flowchart showing an example of a manufacturing method S10 for an optical measuring head according to Embodiment 1 of the present invention. The manufacturing method S10 for an optical measuring head will be described below.

[0039] (1) Preparation of the substrate S (Step S11) The substrate S is, for example, a diamond substrate. In the case of diamond, the thickness of the substrate S is preferably, for example, 50 to several hundred μm (100 μm as an example). This is to balance the strength of the substrate S with the focusing of light to the color center. That is, the thicker the substrate S, the stronger the substrate S is, but it becomes more difficult to focus light to the color center.

[0040] The following explanation will describe the case where an NV center is formed as a color center. As described below, an NV center can be formed by (a) implanting nitrogen ions into the substrate S, or (b) irradiating the substrate S with an electron beam.

[0041] (a) When implanting nitrogen ions into the substrate S, it is preferable that the nitrogen concentration contained in the substrate S be relatively low (for example, less than 1 ppm). This is because a high nitrogen concentration in the substrate S would hinder the formation of NV centers by nitrogen ion implantation. On the other hand, (b) when irradiating the substrate S with an electron beam, it is preferable that the nitrogen concentration contained in the substrate S be relatively high (for example, 1 ppm or more). This is because NV centers are formed from the nitrogen contained in the substrate S.

[0042] Before forming the color center, it is preferable to precisely polish the surface of the substrate S on the object OB side and clean it with acid or the like.

[0043] (2) Formation of color centers (Step S12) Nitrogen ions are accelerated and injected into the substrate S, or the substrate S is irradiated with an electron beam. As a result, an NV center-containing layer Ly is formed in the substrate S. At this time, the depth d of the NV center-containing layer Ly can be adjusted depending on the NV center formation conditions.

[0044] To reduce the depth d of the NV center-containing layer Ly, for example, nitrogen ions are accelerated to a low energy of approximately 20 keV or less and implanted into the substrate S. By reducing the depth d, it becomes easier to measure the coherence time due to surface influences.

[0045] To increase the depth d of the NV center-containing layer Ly, for example, (1) nitrogen ions are accelerated to a high energy greater than approximately 20 keV and injected into the substrate S, or (2) the substrate S is irradiated with an electron beam.

[0046] The substrate S, which has been implanted with nitrogen ions or irradiated with an electron beam, is annealed and cleaned with acid or the like. Prior to annealing, the surface of the substrate S is subjected to oxygen termination or fluorine termination.

[0047] (3) Surface modification (Step S13) The surface of the substrate S on which the color center-containing layer Ly is formed in this manner is chemically modified. A magnetic material or piezoelectric material may be attached to the surface of the substrate S.

[0048] (4) Preparation of the optical measurement head (Step S14) Here, a substrate S having regions A1 to A4 is formed. Figure 6 is a schematic diagram showing an example of an optical measurement head under manufacturing. Methods CA1 and CA2 can be used to prepare this substrate S.

[0049] The manufacturing method of method CA1 includes the steps of forming a color center-containing layer Ly on a plurality of sub-substrates S1 to S4, and connecting the sub-substrates S1 to S4 on which the color center-containing layer Ly is formed to form a substrate S. The created substrate S has the surfaces of the sub-substrates S1 to S4 as regions A1 to A4. At this time, in order to prevent the incidence and emission of light between adjacent sub-substrates S1 to S4, it is preferable to place a light-pass-blocking member, such as metal, at the boundary of the sub-substrates S1 to S4 (regions A1 to A4). This placement can be done, for example, by vapor deposition of a metal material.

[0050] In method CA2, multiple regions A1 to A4 are formed on a single substrate S. For example, during (1) the formation of NV centers on the substrate S (during nitrogen ion implantation, electron beam irradiation) and (2) the surface modification of the substrate S, a mask can be used to identify the regions in which NV centers are formed or the surface is chemically modified. That is, the manufacturing method of method CA2 includes the steps of forming a color center-containing layer Ly in each of the multiple regions of the substrate S and surface modifying each of the multiple regions A1 to A4. In this case as well, it is preferable to place a light-blocking member, such as a metal, at the boundary between regions A1 to A4.

[0051] As described above, a substrate S having multiple regions A1 to A4 can be created, and by connecting optical fibers F1 to F4 to regions A1 to A4, an optical measurement head 20 can be created. Alternatively, four objective lenses Lz1 to Lz4, positioned opposite regions A1 to A4, may be used instead of the optical fibers F1 to F4. Alternatively, one objective lens Lz may be used instead of the four objective lenses Lz1 to Lz4.

[0052] The optical measurement head 20 according to Embodiment 1 comprises a substrate S having a color center-containing layer Ly for measuring the state of an object OB, and an optical input / output section 21 facing or in contact with the substrate S, which emits excitation light to excite the color centers and receives fluorescence from the color centers excited by the excitation light. The substrate S is divided into a plurality of regions A in which at least one of the depth of the color center-containing layer Ly and the surface modification material M that modifies the surface is different.

[0053] The optical measurement method according to Embodiment 1 is an optical measurement method for optically measuring the state of an object OB, and includes an incidence step of injecting excitation light L1 to excite color centers into a substrate S having a color center-containing layer Ly, and an emission step of injecting fluorescence L2 from the color centers excited by the excitation light L1, wherein the substrate S is divided into a plurality of regions A1 to An in which at least one of the depth of the color center-containing layer Ly and the modification material M that modifies the surface is different.

[0054] This facilitates the simultaneous measurement of multiple parameters at the same or very close locations. Furthermore, it facilitates miniaturization of the optical measurement head 20, making it easier to measure temperature, electric field, magnetic field, pH, and ion concentration within a range of approximately 1 mm x 1 mm or less.

[0055] Furthermore, by using optical fibers F to construct the optical input / output section 21, the flexibility of the optical fibers F facilitates diverse measurements in environments with obstacles. Moreover, since the components of the optical fibers F and the substrate S are rigid against temperature and pressure, diverse measurements are facilitated in extreme environments such as the deep sea.

[0056] [Embodiment 2] Figure 7 is a schematic diagram showing an example of an endoscope 50 according to Embodiment 2 of the present invention. The endoscope 50 includes a housing 51, a light guide 52, a camera 53, an air / water supply nozzle 54, a suction / forceps channel 55, and an optical measurement head 20.

[0057] The housing 51 houses various mechanisms and protects them from the outside world. The light guide 52 illuminates the target object OB (in this case, the inside of a living organism) with light, and the camera 53 has an objective lens and photographs the target object OB. The air / water supply nozzle 54 supplies water or air to the inside of the living organism, making it easier to observe the target object OB.

[0058] The suction / forceps port 55 is an opening for aspirating water or air, or for removing treatment instruments 56. The treatment instruments 56 are instruments for collecting biological tissue and performing various procedures (treatment, hemostasis, foreign body retrieval).

[0059] The optical measurement head 20 is used to measure and observe the object OB using the substrate S as a window material. As described above, the substrate S may be connected to the end of an optical fiber, enabling measurement by a light source and a photodetector. Alternatively, fluorescence may be observed using an objective lens (for example, a microscope) instead of an optical fiber.

[0060] In this embodiment, the endoscope 50 has an optical measurement head 20, which allows for the measurement of temperature, pH, and ion concentration within the body, making it easier to detect, for example, the initial location of a tumor.

[0061] (Examples) The following describes examples of the present invention. Here, we show an example of measuring pH using a substrate S on which color centers (NV centers) are formed.

[0062] A diamond substrate measuring 45 mm x 45 mm x 0.5 mm (Thorlabs ELSC45) was used. The concentration of NV centers in this substrate before nitrogen ion implantation was 0.03 ppb or less.

[0063] This substrate was divided into four parts, each designated as substrate S, and nitrogen ions were implanted into them. The nitrogen ion implantation conditions at this time were an acceleration voltage of 5 keV, １４ The density of N is 1 × 10 １４ [cm －２ ]

[0064] The substrate S was subjected to the following treatments in order: acid treatment (a), nitrogen ion implantation (b), acid treatment (c), annealing (d), mixed acid treatment (e), and alkali treatment (f).

[0065] Acid treatment (a) is a process to remove impurities adhering to the surface of the substrate S. If impurities are present on the surface of the substrate S, ions will collide with the impurities during nitrogen ion implantation (b), inhibiting ion implantation into the substrate S.

[0066] The reason for performing acid treatment (c) after nitrogen ion implantation (b) and before annealing (d) is to prevent unexpected reactions caused by annealing of impurities (e.g., adhesive from tape) adhering to the substrate S.

[0067] Annealing (d) was performed in a vacuum at 1000°C for 2 hours. For the mixed acid treatment (e), a mixed acid solution of nitric acid and sulfuric acid in a 1:3 ratio was used.

[0068] The mixed acid treatment (e) and alkali treatment (f) are treatments to convert the substrate S surface into COOH. The mixed acid treatment (e) cleans the surface of the substrate S and generates material that will become the basis of carboxyl groups, and the alkali treatment (f) converts this material into carboxyl groups.

[0069] Figure 8 is a graph showing the pH measurement results for the substrate S in which NV centers were formed in this manner. From Figure 8, the coherence time T of the NV centers of the substrate S is shown. １ However, it can be seen that it changes in response to pH.

[0070] Coherence time T １ This can be calculated based on the time dependence of the quantum state relaxation of the NV center. That is, the time dependence of the quantum state relaxation is fitted by the following equation (1) or (2). a １ exp(-t / T) １ ) ...Formula (1) a １ exp(-t / T) １，１ ) + a ２ exp(-t / T) １，２ ) + b ... Equation (2) t: Time for the quantum state to relax a １ and a ２ : Amplitude of measurement data

[0071] Whether to use equation (1) or equation (2) depends on the type of diamond that makes up the substrate S, and in equation (1), the coherence time T １ However, in equation (2), the coherence time T １，１ and T １，２ This leads to the conclusion.

[0072] As described above, the coherence time T １ This coherence time T is measured. １ The pH can be determined based on this.

[0073] (Summary) The optical measuring head according to the first embodiment comprises a substrate having a color center-containing layer containing color centers for measuring the state of an object, and an optical input / output section facing or in contact with the substrate, which emits excitation light to excite the color centers and receives fluorescence from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the surface modification material modifying the surface of the substrate is different.

[0074] This makes it possible to measure multiple physicochemical quantities at the same or very close locations using multiple regions where at least one of the depths of the color center-containing layer and the surface modification material modifying the substrate surface differs.

[0075] In the second embodiment, the optical measuring head, in the first embodiment, comprises a substrate which includes light transmission prevention members disposed between the plurality of regions.

[0076] The light transmission prevention component ensures the independence of measurements between multiple regions.

[0077] In the third embodiment, the optical measuring head, in the first or second embodiment, has first and second regions that measure at least two selected from temperature, magnetic field, pH, ion concentration, and radicals, respectively.

[0078] At the same or very close location, at least two parameters selected from temperature, magnetic field, pH, and radicals can be measured.

[0079] In the fourth embodiment, the optical measuring head is such that, in the third embodiment, the first or second region is a region for measuring temperature, and the surface modifying material is a hydrophilic polymer.

[0080] This ensures the accuracy of temperature measurements.

[0081] In the fifth embodiment, the optical measuring head, in any of the first to third embodiments, is such that the first or second region is a region for measuring a magnetic field, and the surface modification material is a hydrophilic polymer.

[0082] This ensures the accuracy of magnetic field measurements.

[0083] The optical measuring head according to the sixth embodiment is, in any of the first to third embodiments, wherein the first or second region is a region for measuring pH, and the surface-modifying material is a material containing functional groups that cause proton dissociation depending on pH.

[0084] This ensures the accuracy of pH measurements.

[0085] The optical measuring head according to the seventh embodiment is, in any of the first to third embodiments, wherein the first or second region is a region for measuring the concentration of ions, and the surface modifying material is an anionic or cationic polymer, protein, peptide, crown ether, chelating agent, ionophore, or a derivative thereof.

[0086] The optical measuring head according to the eighth embodiment is, in any of the first to third embodiments, wherein the first or second region is a region for measuring radicals, and the surface modification material is a material that is less likely to cause chemical reactions and nonspecific molecular adsorption by radicals.

[0087] This ensures the accuracy of radical measurement.

[0088] The optical measurement head according to the ninth embodiment, in any of the first to eighth embodiments, comprises a plurality of optical fibers having ends that face or contact the plurality of regions, emitting the excitation light and into which the fluorescence is incident.

[0089] This allows for the use of optical fibers to ensure the accuracy of measurements at the measurement point.

[0090] The optical measuring head according to the tenth embodiment includes a high-frequency field radiating member for applying a high-frequency electric field to a color center, in any of the first to ninth embodiments.

[0091] This makes it possible to perform measurements by applying high-frequency waves (e.g., microwaves) to the color center.

[0092] The endoscope according to the eleventh embodiment is equipped with an optical measuring head as described in any of the first to ninth embodiments.

[0093] This makes it possible to measure multiple physicochemical quantities using an endoscope.

[0094] A method for manufacturing an optical measuring head according to the twelfth embodiment is a method for manufacturing an optical measuring head according to any of the first to ninth embodiments, comprising the steps of: forming a color center containing layer on a plurality of sub-substrates; and connecting the sub-substrates on which the color center containing layer is formed to form the substrate.

[0095] This allows for the manufacture of optical measurement heads by connecting multiple sub-boards.

[0096] A method for manufacturing an optical measuring head according to the 13th embodiment is a method for manufacturing an optical measuring head according to any of the 1st to 9th embodiments, comprising the steps of: forming a color center-containing layer in each of a plurality of regions of a substrate; and surface modifying each of the plurality of regions.

[0097] This allows for the manufacture of optical measurement heads from a single substrate.

[0098] A 14th aspect of optical measurement method is an optical measurement method for optically measuring the state of an object, comprising: an incidence step of incidentally injecting excitation light into a substrate having a color center-containing layer containing color centers, and an emission step of causing fluorescence to be emitted from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the modifying material modifying the surface of the substrate differs.

[0099] This makes it possible to measure multiple physicochemical quantities at the same or very close locations using multiple regions where at least one of the depth of the color center-containing layer from the substrate surface and the surface modification material modifying the substrate surface differ.

[0100] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0101] 1 Optical Measurement System 20 Optical Measurement Head S Substrate A1-A4 Region S1-S4 Sub-substrate Ly Color Center Containing Layer Lz Objective Lens F1-F4 Optical Fiber 11 Light Source 12 Optical Switch 13 Dichroic Mirror 14 Pulse Generator 31 Filter 32 Photodetector 33 Counter 34 Control Unit 41 High-Frequency Oscillator 42 High-Frequency Switch 43 Amplifier

Claims

1. An optical measuring head comprising: a substrate having a color center-containing layer containing color centers for measuring the state of an object; and a light input / output section facing or in contact with the substrate, which emits excitation light to excite the color centers and receives fluorescence from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the surface modification material modifying the surface of the substrate differs.

2. The optical measuring head according to claim 1, wherein the substrate comprises light transmission prevention members disposed between the plurality of regions.

3. The optical measuring head according to claim 1 or 2, wherein the plurality of regions each have first and second regions for measuring at least two selected from temperature, magnetic field, pH, ion concentration, and radicals.

4. The optical measuring head according to claim 3, wherein the first or second region is a region for measuring temperature, and the surface modifying material is a hydrophilic polymer.

5. The optical measuring head according to claim 3, wherein the first or second region is a region for measuring a magnetic field, and the surface modification material is a hydrophilic polymer.

6. The optical measuring head according to claim 3, wherein the first or second region is a region for measuring pH, and the surface-modifying material is a material containing a functional group that causes proton dissociation depending on the pH of the object to be measured.

7. The optical measuring head according to claim 3, wherein the first or second region is a region for measuring the concentration of ions, and the surface modification material is an anionic or cationic polymer, protein, peptide, crown ether, chelating agent, ionophore, or a derivative thereof.

8. The optical measuring head according to claim 3, wherein the first or second region is a region for measuring radicals, and the surface-modifying material is a material that is less likely to undergo chemical reactions and nonspecific molecular adsorption by radicals.

9. The optical measuring head according to claim 1 or 2, wherein the optical input / output section has ends that face or contact the plurality of regions, and comprises a plurality of optical fibers that emit the excitation light and into which the fluorescence is incident.

10. The optical measuring head according to claim 1 or 2, further comprising a high-frequency field radiating member for applying a high-frequency electric field to a color center.

11. An endoscope comprising the optical measuring head according to claim 1 or 2.

12. A method for manufacturing an optical measuring head according to claim 1 or 2, comprising the steps of: forming a color center-containing layer on a plurality of sub-substrates; and connecting the sub-substrates on which the color center-containing layers are formed to form a substrate.

13. A method for manufacturing an optical measuring head according to claim 1 or 2, comprising the steps of: forming a color center-containing layer in each of a plurality of regions of a substrate; and surface-modifying each of the plurality of regions.

14. An optical measurement method for optically measuring the state of an object, comprising: an incidence step of incidentally injecting excitation light into a substrate having a color center-containing layer containing color centers, and an emission step of causing fluorescence to be emitted from the color centers excited by the excitation light, wherein the substrate is divided into a plurality of regions in which at least one of the depth of the color center-containing layer from the surface of the substrate and the modifying material modifying the surface of the substrate differs.

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