Non-invasive substance analyzer

Abstract

The non-invasive substance analyzer (1) comprises an optical fiber circuit (10), a probe light source (26), and a light intensity detector (30). The optical fiber circuit (10) has a sample support area (19). The probe light source (26) emits probe light (27). The optical fiber circuit (10) includes a first optical fiber (11) onto which the probe light (27) is incident, a waveguide-type ring resonator (12), and a second optical fiber (13). The light intensity detector (30) detects the intensity of the first light (27a), which is part of the probe light (27) and is optically coupled to the second optical fiber (13).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a non-invasive substance analyzer. STATE OF THE ART

[0002] Japanese Patent Application Laid-Open No. 2017-519214 (PTL 1) discloses a non-invasive analysis system including an optical medium, an infrared light source, a probe light source, and a photodiode. Specifically, a biological sample is placed on the optical medium. The infrared light source emits infrared light. The infrared light passes through the optical medium and is radiated onto the biological sample. The infrared light is absorbed by the biological sample, causing the biological sample to generate heat. The amount of absorption heat in a biological sample depends on the amount or concentration of biological components in the sample or on the sample surface.

[0003] The probe light source emits probe light, which is visible light, toward the optical medium. The probe light is totally reflected at an interface between the optical medium and the biological sample and exits the optical medium. Heat absorbed by the biological sample is transferred to the optical medium, changing the refractive index of the optical medium. The change in the refractive index of the optical medium affects the total internal reflection of the probe light at the interface between the optical medium and the biological sample, changing the direction of travel of the probe light exiting the optical medium. The photodiode acts as an optical position sensor to detect a change in the direction of travel of the probe light.The amount or concentration of a biological component is measured based on the change in the direction of movement of the probe light, which is detected by the photodiode. For example, if the sample is a patient's skin, the patient's blood glucose level is measured as a biological component. LIST OF CITIONSPATENT LITERATURE

[0004] PTL 1: Japanese Patent Application Laid-Open No. 2017-519214 SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0005] However, in the non-invasive analysis system disclosed in PTL 1, the photodiode has a larger size to cope with the change in the moving direction of the probe light. Therefore, it is difficult to miniaturize the non-invasive analysis system. The present disclosure has been made in view of the above-mentioned problem, and an object of the present disclosure is to provide a non-invasive substance analyzer that can be miniaturized. SOLUTION TO THE PROBLEM

[0006] The non-invasive substance analyzer of the present disclosure includes an optical waveguide circuit, an excitation light source, a probe light source, and a first light intensity detector. The optical waveguide circuit has a first main surface including a sample support area and a second main surface opposite the first main surface. The excitation light source emits excitation light toward a sample placed on the sample support area. The probe light source emits probe light. The optical waveguide circuit includes a first optical waveguide onto which the probe light is incident, a waveguide-type ring resonator optically coupled to the first optical waveguide, and a second optical waveguide optically coupled to the waveguide-type ring resonator.The first light intensity detector is optically coupled to the second optical fiber and detects an intensity of the first light that is part of the probe light and is optically coupled to the second optical fiber. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0007] In the non-invasive substance analyzer of the present disclosure, the first light intensity detector detects a change in the intensity of the probe light coupled to the second optical fiber due to the ON / OFF state of the excitation light, rather than a change in the position of the probe light due to the ON / OFF state of the excitation light. Therefore, the first light intensity detector is miniaturized, thereby miniaturizing the non-invasive substance analyzer. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic plan view of a non-invasive substance analyzer according to a first embodiment; Fig. 2 is a schematic cross-sectional view of the non-invasive substance analyzer according to the first embodiment along a Fig. 1 illustrated cross-section line II-II; Fig. 3 is a schematic cross-sectional view of the non-invasive substance analyzer according to the first embodiment along a Fig. 1 illustrated cross-section line III-III; Fig. 4 is a diagram illustrating a relationship between a phase of a waveguide-type ring resonator and a coupling rate of probe light from a first optical waveguide to the waveguide-type ring resonator; Fig. 5 is a flowchart of a non-invasive substance analysis method according to the first embodiment; Fig. 6 is a schematic plan view of a non-invasive substance analyzer according to a second embodiment; Fig. 7 is a flowchart of a non-invasive substance analysis method according to the second embodiment; Fig. 8 is a schematic plan view of a non-invasive substance analyzer according to a third embodiment; Fig. 9 is a schematic cross-sectional view of the non-invasive substance analyzer according to the third embodiment along a Fig. 8 illustrated cross-section line IX-IX; Fig. 10 is a diagram illustrating a relationship between a phase of a waveguide-type ring resonator and a coupling rate of probe light from a first optical waveguide to the waveguide-type ring resonator; Fig. 11 is a flowchart of a non-invasive substance analysis method according to the third embodiment; Fig. 12 is a schematic plan view of a non-invasive substance analyzer according to a fourth embodiment; Fig. 13 is a schematic plan view of a non-invasive substance analyzer according to a fifth embodiment; Fig. 14 is a schematic cross-sectional view of the non-invasive substance analyzer according to the fifth embodiment along a Fig. 13 illustrated cross-section line XIV-XIV; Fig. 15 is a schematic plan view of a non-invasive substance analyzer according to a sixth embodiment; Fig. 16 is a schematic cross-sectional view of the non-invasive substance analyzer according to the sixth embodiment taken along a Fig. 15 illustrated cross-section line XVI-XVI; Fig. 17 is a schematic plan view of a non-invasive substance analyzer according to a seventh embodiment; Fig. 18 is a schematic cross-sectional view of the non-invasive substance analyzer according to the seventh embodiment taken along a Fig. 17 illustrated cross-section line XVIII-XVIII; Fig. 19 is a schematic cross-sectional view of a non-invasive substance analyzer according to a modification of the seventh embodiment; Fig. 20 is a schematic plan view of a non-invasive substance analyzer according to an eighth embodiment; and Fig. 21 is a schematic cross-sectional view of the non-invasive substance analyzer of the eighth embodiment taken along a Fig. 20 illustrated cross-section line XXI-XXI. DESCRIPTION OF EMBODIMENTS

[0008] Embodiments are described below. The same components are identified by the same reference numerals, and their description will not be repeated. First embodiment

[0009] A non-invasive substance analyzer 1 according to a first embodiment is described with reference to Fig. 1 to 4. With reference to the Fig. 1 to 3, the non-invasive substance analyzer 1 mainly includes an optical fiber circuit 10, an excitation light source 23, a probe light source 26, a light intensity detector 30, and a substance analysis unit 33.

[0010] With reference to Fig. 1, the probe light source 26 emits probe light 27. The probe light source 26 is, for example, a laser light source, such as a laser diode. In the present embodiment, the probe light source 26 is arranged outside the optical waveguide circuit 10. The probe light source 26 can be arranged on a substrate 15.

[0011] The wavelength of the probe light 27 is, for example, 1100 nm or more. The wavelength of the probe light 27 may be 1300 nm or more. The wavelength of the probe light 27 is, for example, 1700 nm or less. Thus, an inexpensive laser diode for optical communication, such as an InGaAsP laser diode or an InGaNAs laser diode, can be used as the probe light source 26. Furthermore, since the probe light 27 is not visible light, the risk of the probe light 27 damaging the human eye can be reduced. The power of the probe light 27 is, for example, 5 mW or less. Therefore, the risk of the probe light 27 damaging the human eye can be reduced.

[0012] With reference to the Fig. 1 to 3, the optical waveguide circuit 10 has a main surface 10a and a main surface 10b opposite the main surface 10a. The optical waveguide circuit 10 includes a substrate 15, a first optical waveguide 11, a waveguide-type ring resonator 12, a second optical waveguide 13, and a cladding layer 14. The optical waveguide circuit 10 may further include termination sections 16 and 17.

[0013] The substrate 15 supports the first optical waveguide 11, the waveguide-type ring resonator 12, the second optical waveguide 13, and the cladding layer 14. The substrate 15 has a main surface 10b. The substrate 15 is, for example, a silicon substrate.

[0014] The probe light 27 is incident on the first optical waveguide 11 of the optical waveguide circuit 10. The first optical waveguide 11 includes an end 11a onto which the probe light 27 is incident, and an end 11b opposite the end 11a. The first optical waveguide 11 has a higher refractive index than the cladding layer 14. The probe light 27 propagates in the first optical waveguide 11. The first optical waveguide 11 is, for example, a silicon waveguide.

[0015] The waveguide-type ring resonator 12 is optically coupled to the first optical waveguide 11. The waveguide-type ring resonator 12 has a higher refractive index than the cladding layer 14. The probe light 27 propagates in the waveguide-type ring resonator 12. The waveguide-type ring resonator 12 exhibits a thermo-optic effect. The waveguide-type ring resonator 12 is, for example, a silicon waveguide. The thermo-optic coefficient of silicon is 2.3 × 10 -4 (K -1 ). Silicon has a relatively high thermo-optic coefficient among optical materials for fiber optics.

[0016] The second optical waveguide 13 is optically coupled to the waveguide-type ring resonator 12. The second optical waveguide 13 has a higher refractive index than the cladding layer 14. The probe light 27 propagates in the second optical waveguide 13. In a plan view of the main surface 10a, the second optical waveguide 13 is arranged symmetrically to the first optical waveguide 11 with respect to the waveguide-type ring resonator 12. The second optical waveguide 13 includes an end 13a optically coupled to the light intensity detector 30 and an end 13b opposite the end 13a. The ends 11a and 13a are located on the same side of the waveguide-type ring resonator 12. The ends 11b and 13b are located on the same side of the waveguide-type ring resonator 12.

[0017] The cladding layer 14 separates the first optical waveguide 11, the waveguide-type ring resonator 12, and the second optical waveguide 13 from the substrate 15. The cladding layer 14 covers the first optical waveguide 11, the waveguide-type ring resonator 12, and the second optical waveguide 13. The cladding layer 14 has a main surface 10a. The thermal conductivity of the cladding layer 14 is lower than the thermal conductivity of the substrate 15. The cladding layer 14 is made of silicate glass, for example.

[0018] The probe light 27 incident from the probe light source 26 onto the first optical waveguide 11 is mainly divided into first light 27a optically coupled to the second optical waveguide 13 via the waveguide-type ring resonator 12 and second light 27b propagating in the first optical waveguide 11 without being coupled to the waveguide-type ring resonator 12. Fig. Figure 4 illustrates a coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12. The coupling rate of the probe light 27 from the waveguide-type ring resonator 12 to the second optical waveguide 13 is the same as the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12. The horizontal axis in Fig. 4 represents a phase of the waveguide type ring resonator 12 with respect to the wavelength of the probe light 27, which is defined by the following equation (1). Phase of the waveguide type ring resonator 12 = 2π × (nL) / λ

[0019] Where n represents a refractive index of the waveguide-type ring resonator 12, L represents a length of the waveguide-type ring resonator 12, NL represents a length of the beam path of the waveguide-type ring resonator 12, and λ represents the wavelength of the probe light 27. In Fig. 4 is m a natural number.

[0020] When the phase of the waveguide-type ring resonator 12 is an even multiple of π, the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 is maximum. As the phase of the waveguide-type ring resonator 12 approaches an even multiple of π from an odd multiple of π, the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 changes more rapidly.

[0021] The free spectral range Δf of the waveguide-type ring resonator 12 (ie, the interval of a frequency at which the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 is maximum) is given by equation (2). Δf=c / (nL)=(fλ) / (nL)

[0022] Where c represents the speed of light in a vacuum.

[0023] Referring to equations (1) and (2), when the refractive index n of the waveguide-type ring resonator 12 or the wavelength λ of the probe light 27 changes, the phase and the free spectral range Δf of the waveguide-type ring resonator 12 change, causing the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 to change.

[0024] With reference to Fig. 1, the termination portion 16 is provided at the end 11b of the first optical waveguide 11. The termination portion 17 is provided at the end 13b of the second optical waveguide 13. The termination portion 16 or 17 is a light diffuser that scatters the probe light 27 or a light absorber that absorbs the probe light 27. The termination portion 16 or 17 scatters or absorbs the probe light 27 to reduce the returning light from the probe light 27 traveling toward the waveguide-type ring resonator 12, the probe light source 26, and the light intensity detector 30. The termination portion 16 or 17 is formed, for example, from a tapered waveguide that slightly scatters light to the outside of the waveguide and an electrode (for example, a metal electrode) that absorbs scattered light.

[0025] With reference to the Fig. 1 to 3, the main surface 10a of the optical waveguide circuit 10 includes a sample support area 19 onto which a sample 21 is placed. The sample 21 is, for example, a patient's skin or body fluid. In a plan view of the main surface 10a, the sample support area 19 is located within the waveguide-type ring resonator 12 and is surrounded by the waveguide-type ring resonator 12.

[0026] With reference to the Fig. 2 and Fig. 3, the excitation light source 23 emits excitation light 24 toward the sample 21 placed on the sample support portion 19. The wavelength of the excitation light 24 is determined according to the absorption wavelength of a substance in the sample 21 or on the surface of the sample 21. The wavelength of the excitation light 24 may be longer than the wavelength of the probe light 27. The excitation light 24 is, for example, light in the mid-infrared range. The wavelength of the excitation light 24 is, for example, 6.0 µm or more. The wavelength of the excitation light 24 may be 8.0 µm or more. The wavelength of the excitation light 24 is, for example, 13.0 µm or less. The wavelength of the excitation light 24 may be 11.0 µm or less. The excitation light 24 may have a variety of wavelengths.For example, when the non-invasive substance analyzer 1 is used to measure a patient's blood sugar level, the wavelength range of the excitation light 24 is a wavelength range that includes the wavelength of the fingerprint spectrum of blood sugar (for example, a wavelength range of 8.5 μm or more and 10 μm or less). The excitation light source 23 is, for example, a quantum cascade laser capable of emitting broadband light in the mid-infrared range. The sample 21 can be irradiated with the excitation light 24 together with reference light that is not absorbed by the substance in the sample 21 or on the surface of the sample 21.

[0027] The excitation light 24 is absorbed by the substance in the sample 21 or on the surface of the sample 21. The absorption of the excitation light 24 by the substance generates absorption heat in the sample 21. The absorption heat in the sample 21 is conducted to the waveguide-type ring resonator 12, causing the temperature of the waveguide-type ring resonator 12 to change. The waveguide-type ring resonator 12 exhibits a thermo-optical effect. Therefore, when the temperature of the waveguide-type ring resonator 12 changes, the refractive index of the waveguide-type ring resonator 12 changes, causing the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 to change.

[0028] The substance in the sample 21 or on the surface of the sample 21 is, for example, a biological component. Specifically, when the non-invasive substance analyzer 1 is used to measure a patient's blood glucose level, the substance to be analyzed by the non-invasive substance analyzer 1 is blood glucose contained in the interstitial fluid in the patient's epidermal tissue.

[0029] In the present embodiment, the excitation light source 23 is arranged facing the main surface 10a. The excitation light 24 is incident on the sample 21 from the side of the main surface 10a. The excitation light 24 is incident on the sample 21 without passing through the substrate 15. If the substrate 15 is transparent to the excitation light 24, the excitation light source 23 can be arranged opposite the main surface 10b of the optical waveguide circuit 10, and the excitation light 24 can be incident on the sample 21 through the substrate 15.

[0030] With reference to Fig. 1, the light intensity detector 30 is optically coupled to the end 13a of the second optical waveguide 13. The light intensity detector 30 detects the intensity of the first light 27a, which is part of the probe light 27 and is optically coupled to the second optical waveguide 13. The light intensity detector 30 measures a first intensity of the first light 27a incident on the light intensity detector 30 when the sample 21 is not irradiated with the excitation light 24, and a second intensity of the first light 27a incident on the light intensity detector 30 when the sample 21 is irradiated with the excitation light 24.As described above, between a time when the sample 21 is not irradiated with the excitation light 24 and a time when the sample 21 is irradiated with the excitation light 24, the temperature of the waveguide-type ring resonator 12 changes, causing the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 to change. Therefore, the second intensity of the first light 27a differs from the first intensity of the first light 27a.

[0031] The light intensity detector 30 outputs the first intensity of the first light 27a and the second intensity of the first light 27a to the substance analysis unit 33. The light intensity detector 30 is, for example, a photodiode, such as a SiGe photodiode. In the present embodiment, the light intensity detector 30 is arranged on the substrate 15. The light intensity detector 30 may be arranged outside the optical waveguide circuit 10.

[0032] The non-invasive substance analyzer 1 analyzes the substance based on the intensity of the first light 27a, which is part of the probe light 27 and is optically coupled to the second optical fiber 13. With reference to Fig. 1, the substance analysis unit 33 is connected to the light intensity detector 30. The substance analysis unit 33 receives the first intensity of the first light 27a and the second intensity of the first light 27a from the light intensity detector 30. The substance analysis unit 33 determines the type, amount, or concentration of the substance in the sample 21 or on the surface of the sample 21 based on the first intensity of the first light 27a and the second intensity of the first light 27a.

[0033] The substance analysis unit 33 is, for example, a microcomputer that includes a processor, a random access memory (RAM), and a storage device such as a read-only memory (ROM). A CPU (central processing unit), for example, can be used as the processor. The RAM functions as a working memory that temporarily stores data to be processed by the processor. The storage device stores, for example, a program to be executed by the processor. In the present embodiment, when the processor executes the program stored in the storage device, the substance analysis unit 33 determines the type of substance in the sample 21 or on the surface of the sample 21, or calculates the amount or concentration of the substance in the sample 21 or on the surface of the sample 21 based on the first intensity of the first light 27a and the second intensity of the first light 27a.The various processes in the substance analysis unit 33 are not limited to being executed by software and can be executed by dedicated hardware (electronic circuit).

[0034] A non-invasive substance analysis method of the present embodiment using the non-invasive substance analyzer 1 will be mainly described with reference to Fig. 5 described.

[0035] The non-invasive substance analysis method of the present embodiment involves placing the sample 21 on the sample support area 19 (S1). When there is a difference between the temperature of the optical waveguide circuit 10 and the temperature of the sample 21, heat transfer occurs between the optical waveguide circuit 10 and the sample 21. Due to this heat transfer, it is difficult to detect a change in the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 due to the heat absorption in the sample 21, making it difficult to analyze the substance in the sample 21 or on the surface of the sample 21. Therefore, step S3, to be described later, is not performed until a thermal equilibrium is reached between the optical waveguide circuit 10 and the sample 21.After the thermal equilibrium between the optical fiber circuit 10 and the sample 21 is achieved, the non-invasive substance analyzer 1 is used to analyze the substance in the sample 21 or on the surface of the sample 21.

[0036] The non-invasive substance analysis method of the present embodiment involves measuring the first intensity of the first light 27a incident on the light intensity detector 30 without irradiating the sample 21 with the excitation light 24 (S3). Since the sample 21 is not irradiated with the excitation light 24 (an OFF state of the excitation light 24), no absorption heat is generated in the sample 21.

[0037] The non-invasive substance analysis method of the present embodiment includes measuring the second intensity of the first light 27a incident on the light intensity detector 30 while the sample 21 is irradiated with the excitation light 24 (S4). Since the sample 21 is irradiated with the excitation light 24 (an ON state of the excitation light 24), the excitation light 24 is absorbed by the substance in the sample 21 or on the surface of the sample 21. Absorption heat is generated in the sample 21. The absorption heat in the sample 21 is conducted to the waveguide-type ring resonator 12. The temperature of the waveguide-type ring resonator 12 changes, and thereby the refractive index of the waveguide-type ring resonator 12 changes. Accordingly, the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 changes.Therefore, the second intensity of the first light 27a differs from the first intensity of the first light 27a.

[0038] The non-invasive substance analysis method of the present embodiment includes determining the amount or concentration of the substance in the sample 21 or on the surface of the sample 21 based on the first intensity of the first light 27a and the second intensity of the first light 27a (S5). For example, the substance analysis unit 33 is connected to a memory (not shown). A data table in which the wavelength of the excitation light 24 is associated with the type of substance and a data table in which the difference between the first intensity and the second intensity is associated with the amount or concentration of the substance are stored in the memory. The substance analysis unit 33 determines the type of substance and calculates the amount or concentration of the substance with reference to these data tables.

[0039] Effects of the non-invasive substance analyzer 1 of the present embodiment will be described.

[0040] The non-invasive substance analyzer 1 of the present embodiment includes an optical waveguide circuit 10, an excitation light source 23, a probe light source 26, and a first light intensity detector (a light intensity detector 30). The optical waveguide circuit 10 has a first main surface (a main surface 10a) including a sample support area 19, and a second main surface (a main surface 10b) opposite the first main surface. The excitation light source 23 emits excitation light 24 toward a sample 21 placed on the sample support area 19. The probe light source 26 emits probe light 27. The optical waveguide circuit 10 includes a first optical waveguide 11 onto which the probe light 27 is incident, a waveguide-type ring resonator 12 optically coupled to the first optical waveguide 11, and a second optical waveguide 13 optically coupled to the waveguide-type ring resonator 12.The first light intensity detector is optically coupled to the second optical fiber 13 and detects the intensity of the first light 27a, which is part of the probe light 27 and is optically coupled to the second optical fiber 13.

[0041] The first light intensity detector (the light intensity detector 30) detects a change in the intensity of the first light 27a coupled to the second optical fiber 13 due to the ON / OFF state of the excitation light 24, rather than a change in the position of the probe light 27 due to the ON / OFF state of the excitation light 24. Therefore, the first light intensity detector is miniaturized, and thereby the non-invasive substance analyzer 1 is miniaturized.

[0042] In the non-invasive substance analyzer 1 of the present embodiment, the sample support portion 19 is located inside the waveguide-type ring resonator 12 in a plan view of the first main surface (the main surface 10a).

[0043] In a plan view of the first main surface (the main surface 10a), the sample support region 19 is surrounded by the waveguide-type ring resonator 12. The absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12. The change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Therefore, the non-invasive substance analyzer 1 can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy.

[0044] The non-invasive substance analyzer 1 according to the present embodiment further includes a substance analysis unit 33 that analyzes a substance in the sample 21 or on the surface of the sample 21 based on the intensity of the first light 27a. Therefore, the non-invasive substance analyzer 1 is miniaturized.

[0045] In the non-invasive substance analyzer 1 of the present embodiment, the optical waveguide circuit 10 includes a first termination portion (a termination portion 17). The second optical waveguide 13 includes a first end (an end 13a) optically coupled to the first light intensity detector (the light intensity detector 30) and a second end (an end 13b) opposite the first end. The first termination portion is provided at the second end of the second optical waveguide 13 and scatters or absorbs the probe light 27.

[0046] The first termination section (the termination section 17) scatters or absorbs the probe light 27 to prevent the returning light from the probe light 27 from coupling to the waveguide-type ring resonator 12, the probe light source 26, and the first light intensity detector (the light intensity detector 30). Therefore, the non-invasive substance analyzer 1 can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy.

[0047] In the non-invasive substance analyzer 1 of the present embodiment, the optical waveguide circuit 10 includes a second termination portion (a termination portion 16). The first optical waveguide 11 includes a third end (an end 11a) onto which the probe light 27 is incident, and a fourth end (an end 11b) opposite the third end. The second termination portion is provided at the fourth end of the first optical waveguide 11 and scatters or absorbs the probe light 27.

[0048] The second termination section (termination section 16) scatters or absorbs the probe light 27 to prevent the returning light from the probe light 27 from coupling to the waveguide-type ring resonator 12, the probe light source 26, and the first light intensity detector (the light intensity detector 30). Therefore, the non-invasive substance analyzer 1 can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy.

[0049] In the non-invasive substance analyzer 1 of the present embodiment, the waveguide type ring resonator 12 is a silicon waveguide.

[0050] Silicon has a relatively high thermo-optic coefficient among optical materials for optical waveguides. Therefore, even if the amount of absorption heat in the sample 21 is small due to reasons such as the amount of substance in the sample 21 or on the surface of the sample 21, the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes large. This allows the non-invasive substance analyzer 1 to analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy. Second embodiment

[0051] A non-invasive substance analyzer 1b according to a second embodiment is described with reference to Fig. 6. The non-invasive substance analyzer 1b of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1 of the first embodiment, but differs mainly in the following points.

[0052] The non-invasive substance analyzer 1b includes a light intensity detector 37 instead of the terminal section 16 (see Fig. 1). The light intensity detector 37 is optically coupled to the end 11b of the first optical waveguide 11. The light intensity detector 37 detects the intensity of the second light 27b, which is part of the probe light 27 and propagates in the first optical waveguide 11 without being coupled to the waveguide-type ring resonator 12.

[0053] The non-invasive substance analyzer 1b analyzes the substance in the sample 21 or on the surface of the sample 21 based on the intensity of the first light 27a, which is part of the probe light 27 and is optically coupled to the second optical waveguide 13, and the intensity of the second light 27b, which is part of the probe light 27 and propagates in the first optical waveguide 11 without being coupled to the waveguide-type ring resonator 12. For example, the non-invasive substance analyzer 1b analyzes the substance in the sample 21 or on the surface of the sample 21 based on a difference between the intensity of the first light 27a, which is part of the probe light 27 and is optically coupled to the second optical waveguide 13, and the intensity of the second light 27b, which is part of the probe light 27 and propagates in the first optical waveguide 11 without being coupled to the waveguide-type ring resonator 12.

[0054] Specifically, the light intensity detector 37 measures a third intensity of the second light 27b incident on the light intensity detector 37 when the sample 21 is not irradiated with the excitation light 24, and a fourth intensity of the second light 27b incident on the light intensity detector 37 when the sample 21 is irradiated with the excitation light 24. As described in the first embodiment, between a time when the sample 21 is not irradiated with the excitation light 24 and a time when the sample 21 is irradiated with the excitation light 24, the temperature of the waveguide-type ring resonator 12 changes, causing the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 to change. Therefore, the fourth intensity of the second light 27b differs from the third intensity of the second light 27b.

[0055] The light intensity detector 37 outputs the third intensity of the second light 27b and the fourth intensity of the second light 27b to the substance analysis unit 33. The light intensity detector 37 is, for example, a photodiode, such as a SiGe photodiode. In the present embodiment, the light intensity detector 37 is arranged on the substrate 15. The light intensity detector 37 may be arranged outside the optical waveguide circuit 10.

[0056] The substance analysis unit 33 is also connected to a light intensity detector 37 in addition to the light intensity detector 30. The substance analysis unit 33 receives the first intensity of the first light 27a and the second intensity of the first light 27a from the light intensity detector 30 and receives the third intensity of the second light 27b and the fourth intensity of the second light 27b from the light intensity detector 37. The substance analysis unit 33 determines the type, amount, or concentration of the substance in the sample 21 or on the surface of the sample 21 based on the first intensity of the first light 27a, the second intensity of the first light 27a, the third intensity of the second light 27b, and the fourth intensity of the second light 27b.

[0057] A non-invasive substance analysis method of the present embodiment using the non-invasive substance analyzer 1b will be mainly described with reference to Fig. 7. The non-invasive substance analysis method of the present embodiment is similar to the non-invasive substance analysis method of the first embodiment, but differs from the non-invasive substance analysis method of the first embodiment in the following points.

[0058] The non-invasive substance analysis method of the present embodiment includes, following step S1, measuring the first intensity of the first light 27a incident on the light intensity detector 30 and the third intensity of the second light 27b incident on the light intensity detector 37 without irradiating the sample 21 with the excitation light 24 (S13). Since the sample 21 is not irradiated with the excitation light 24 (an OFF state of the excitation light 24), no absorption heat is generated in the sample 21.

[0059] The non-invasive substance analysis method of the present embodiment includes measuring the second intensity of the first light 27a incident on the light intensity detector 30 and the fourth intensity of the second light 27b incident on the light intensity detector 37 while the sample 21 is irradiated with the excitation light 24 (an ON state of the excitation light 24), the excitation light 24 is absorbed by the substance in the sample 21 or on the surface of the sample 21. Absorption heat is generated in the sample 21. The absorption heat in the sample 21 is conducted to the waveguide-type ring resonator 12. The temperature of the waveguide-type ring resonator 12 changes, and thereby the refractive index of the waveguide-type ring resonator 12 changes.Accordingly, the coupling rate of the probe light 27 from the first optical waveguide 11 to the second optical waveguide 13 via the waveguide-type ring resonator 12 changes. Therefore, the second intensity of the first light 27a differs from the first intensity of the first light 27a. The fourth intensity of the second light 27b differs from the third intensity of the second light 27b.

[0060] The non-invasive substance analysis method of the present embodiment includes determining the amount or concentration of the substance in the sample 21 or on the surface of the sample 21 based on the first intensity of the first light 27a, the second intensity of the first light 27a, the third intensity of the second light 27b, and the fourth intensity of the second light 27b (S15). For example, the substance analysis unit 33 calculates a difference between the first intensity of the first light 27a and the third intensity of the second light 27b as a first difference signal when the excitation light 24 is off. The substance analysis unit 33 calculates a difference between the second intensity of the first light 27a and the fourth intensity of the second light 27b as a second difference signal when the excitation light 24 is on.The memory stores a data table in which the wavelength of the excitation light 24 is associated with the type of substance, and a data table in which a difference between the first difference signal and the second difference signal is associated with the amount or concentration of the substance. The substance analysis unit 33 determines the type of substance and calculates the amount or concentration of the substance by referring to these data tables.

[0061] The non-invasive substance analyzer 1b of the present embodiment further has the following effects in addition to the effects of the non-invasive substance analyzer 1 of the first embodiment.

[0062] The non-invasive substance analyzer 1b of the present embodiment further includes a second light intensity detector (a light intensity detector 37). The second light intensity detector is optically coupled to the first optical waveguide 11 and detects the intensity of the second light 27b, which is part of the probe light 27 and propagates in the first optical waveguide 11 without being coupled to the waveguide-type ring resonator 12.

[0063] The non-invasive substance analyzer 1b can analyze the substance in the sample 21 or on the surface of the sample 21 based on the difference between the intensity of the first light 27a measured by the first light intensity detector (the light intensity detector 30) and the intensity of the second light 27b measured by the second light intensity detector (the light intensity detector 37). The intensity of the first light 27a may include a noise component due to a slight disturbance in the optical waveguide circuit 10. The slight disturbance is, for example, roughness of a light incident surface of the optical waveguide circuit 10 and roughness of a sidewall of the optical waveguide due to a manufacturing process.By determining the difference between the intensity of the first light 27a and the intensity of the second light 27b, the noise component in the intensity of the first light 27a is suppressed by the noise component in the intensity of the second light 27b. Therefore, the difference between the intensity of the first light 27a and the intensity of the second light 27b has a higher S / N ratio than the intensity of the first light 27a. The non-invasive substance analyzer 1b can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy.

[0064] The non-invasive substance analyzer 1b of the present embodiment further includes a substance analysis unit 33 that analyzes a substance in the sample 21 or on the surface of the sample 21 based on a difference between the intensity of the first light 27a and the intensity of the second light 27b.

[0065] By determining the difference between the intensity of the first light 27a and the intensity of the second light 27b, the noise component in the intensity of the first light 27a is canceled by the noise component in the intensity of the second light 27b. Therefore, the difference between the intensity of the first light 27a and the intensity of the second light 27b has a higher S / N ratio than the intensity of the first light 27a. The non-invasive substance analyzer 1b can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy. Third embodiment

[0066] A non-invasive substance analyzer 1c according to a third embodiment is described with reference to the Fig. 8 to 10. The non-invasive substance analyzer 1c of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1 of the first embodiment, but differs mainly in the following points.

[0067] With reference to the Fig. 8 and Fig. 9, the non-invasive substance analyzer 1c of the present embodiment includes a temperature controller 40 that controls a temperature of the waveguide-type ring resonator 12. The temperature controller 40 is, for example, a heater such as a heating electrode. When a current is applied to the heater, the heater generates heat to change the temperature of the waveguide-type ring resonator 12. The heater is made of, for example, a high-strength metal material such as tantalum, platinum, or titanium. The temperature controller 40 is arranged closer to the main surface 10a than the waveguide-type ring resonator 12. The temperature controller 40 is separated from the waveguide-type ring resonator 12 by the cladding layer 14.

[0068] The temperature controller 40 has a band shape along the circumferential direction of the waveguide-type ring resonator 12 in a plan view of the main surface 10a. In the plan view of the main surface 10a, the length of the temperature controller 40 in the circumferential direction of the waveguide-type ring resonator 12 is, for example, 50% or less of the length of the waveguide-type ring resonator 12 in the circumferential direction. Therefore, the temperature controller 40 is prevented from supplying excessive heat to the optical waveguide circuit 10 compared to the absorption heat in the sample 21. Thus, it is possible to prevent the detection sensitivity of the absorption heat in the sample 21 by the temperature controller 40 from being significantly reduced.The length of the temperature controller 40 in the circumferential direction of the waveguide-type ring resonator 12 may be 20% or less of the length of the waveguide-type ring resonator 12 in the circumferential direction of the waveguide-type ring resonator 12.

[0069] The phase of the waveguide-type ring resonator 12 is given by equation (1) of the first embodiment. Therefore, as shown in Fig. 10 illustrates that when the temperature controller 40 is used to control the temperature of the waveguide-type ring resonator 12, the initial phase of the waveguide-type ring resonator 12 (the phase of the waveguide-type ring resonator 12 when the excitation light 24 is off) is adjusted. In the present embodiment, the temperature of the temperature controller 40 is adjusted so that the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Thus, the initial phase of the waveguide-type ring resonator 12 is adjusted.

[0070] For example, the waveguide type ring resonator 12 has, with reference to Fig. 10, when the temperature controller 40 is turned off, has an initial phase of p1. In the waveguide-type ring resonator 12 having an initial phase of p1, the change in the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 due to the ON / OFF state of the excitation light 24 is small, and thus the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 is small.

[0071] The temperature controller 40 is used to control the temperature of the waveguide-type ring resonator 12 to set the initial phase of the waveguide-type ring resonator 12 to p2. In the waveguide-type ring resonator 12 having an initial phase of p2, the change in the coupling rate of the probe light 27 from the first optical waveguide 11 to the waveguide-type ring resonator 12 becomes larger due to the ON / OFF state of the excitation light 24, and thereby the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Therefore, the absorption heat in the sample 21 can be detected with higher accuracy. Accordingly, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0072] A non-invasive substance analysis method of the present embodiment using the non-invasive substance analyzer 1c will be mainly described with reference to Fig. 11. The non-invasive substance analysis method of the present embodiment is similar to the non-invasive substance analysis method of the first embodiment (see Fig. 5), but differs from the non-invasive substance analysis method of the first embodiment in the following points.

[0073] The non-invasive substance analysis method according to the present embodiment further includes controlling the initial phase of the waveguide-type ring resonator 12 using the temperature controller 40 (S2) between step S1 and step S3. Specifically, the intensity of the first light 27a is measured using the light intensity detector 30 while changing the temperature of the waveguide-type ring resonator 12 using the temperature controller 40 without irradiating the sample 21 with the excitation light 24. The temperature of the temperature controller 40 is adjusted in such a manner that a ratio of the change in the intensity of the first light 27a to the change in the temperature of the temperature controller 40 (i.e., the change in the temperature of the waveguide-type ring resonator 12) becomes larger, preferably the ratio becomes maximum. Thus, the initial phase of the waveguide-type ring resonator 12 is adjusted.

[0074] The non-invasive substance analyzer 1c of the present embodiment further has the following effects in addition to the effects of the non-invasive substance analyzer 1 of the first embodiment.

[0075] The non-invasive substance analyzer 1c according to the present embodiment further includes a temperature controller 40 that controls a temperature of the waveguide-type ring resonator 12.

[0076] By controlling the temperature of the waveguide-type ring resonator 12 using the temperature controller 40, the initial phase of the waveguide-type ring resonator 12 (the phase of the waveguide-type ring resonator 12 when the excitation light 24 is off) can be adjusted so that the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0077] In the non-invasive substance analyzer 1c of the present embodiment, in a plan view of the first main surface (the main surface 10a), the length of the temperature controller 40 in the circumferential direction of the waveguide-type ring resonator 12 is 50% or less of the length of the waveguide-type ring resonator 12 in the circumferential direction of the waveguide-type ring resonator 12.

[0078] Therefore, the temperature controller 40 is prevented from supplying excessive heat to the optical waveguide circuit 10 compared to the heat absorption in the sample 21. Thus, it is possible to prevent the detection sensitivity of the heat absorption in the sample 21 from being significantly reduced by the temperature controller 40. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy. Fourth embodiment

[0079] A non-invasive substance analyzer 1d according to a fourth embodiment is described with reference to Fig. 12. The non-invasive substance analyzer 1d of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1 of the first embodiment, but differs mainly in the following points.

[0080] The non-invasive substance analyzer 1d further includes a temperature controller 42 that controls the temperature of the probe light source 26. The temperature controller 42 is, for example, a heater or a Peltier element. When the temperature of the probe light source 26 is changed by the temperature controller 42, the wavelength of the probe light 27 emitted by the probe light source 26 changes.

[0081] Since the phase of the waveguide-type ring resonator 12 is given by equation (1) of the first embodiment, when the wavelength of the probe light 27 changes, the initial phase of the waveguide-type ring resonator 12 changes (the phase of the waveguide-type ring resonator 12 when the excitation light 24 is off). In the present embodiment, the temperature controller 42 is used to control the temperature of the probe light source 26 to control the wavelength of the probe light 27. The wavelength of the probe light 27 is adjusted so that the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Thus, the initial phase of the waveguide-type ring resonator 12 is adjusted.

[0082] The non-invasive substance analyzer 1d of the present embodiment further has the following effects in addition to the effects of the non-invasive substance analyzer 1 of the first embodiment.

[0083] The non-invasive substance analyzer 1d of the present embodiment further includes a temperature controller 42 that controls a temperature of the probe light source 26.

[0084] The temperature controller 42 is used to control the temperature of the probe light source 26 to control the wavelength of the probe light 27. By controlling the wavelength of the probe light 27, the initial phase of the waveguide-type ring resonator 12 (the phase of the waveguide-type ring resonator 12 when the excitation light 24 is off) can be adjusted so that the change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Thus, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy. Fifth embodiment

[0085] A non-invasive substance analyzer 1e according to a fifth embodiment is described with reference to the Fig. 13 and Fig. 14. The non-invasive substance analyzer 1e of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1 of the first embodiment, but differs mainly in the following points.

[0086] In the present embodiment, the optical waveguide circuit 10 is provided with a recess 15c on a surface 15a of the substrate 15 facing the waveguide-type ring resonator 12. The recess 15c faces the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other). The recess 15c is formed by cutting or etching the substrate 15. In a plan view of the main surface 10a, the recess 15c overlaps the waveguide-type ring resonator 12.

[0087] The optical waveguide circuit 10 includes a thermal insulation member 44. The recess 15c is filled with the thermal insulation member 44. The thermal insulation member 44 has a lower thermal conductivity than the substrate 15. In the present embodiment, the thermal insulation member 44 is made of the same material (e.g., silicate glass) as that of the cladding layer 14. The thermal insulation member 44 may be made of a material having a lower thermal conductivity than the substrate 15 and may be made of a material different from that of the cladding layer 14. The thermal insulation member 44 faces the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other).

[0088] The non-invasive substance analyzer 1e of the present embodiment further has the following effects in addition to the effects of the non-invasive substance analyzer 1 of the first embodiment.

[0089] In the non-invasive substance analyzer 1e of the present embodiment, the optical waveguide circuit 10 includes a substrate 15 supporting the waveguide-type ring resonator 12 and a heat insulating member 44 having a lower thermal conductivity than the substrate 15. A recess 15c, which overlaps the waveguide-type ring resonator 12 in a plan view of the first main surface (main surface 10a), is provided on a surface 15a of the substrate 15 facing the waveguide-type ring resonator 12. The recess 15c is filled with the heat insulating member 44.

[0090] The heat insulating member 44 makes it difficult for the absorption heat in the sample 21 to escape to the substrate 15. The change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes greater. Therefore, the non-invasive substance analyzer 1e can analyze the substance in the sample 21 or on the surface of the sample 21 with higher accuracy. Sixth embodiment

[0091] A non-invasive substance analyzer 1f according to a sixth embodiment will be described with reference to the Fig. 15 and Fig. 16. The non-invasive substance analyzer 1f of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1 of the first embodiment, but differs mainly in the following points.

[0092] In the non-invasive substance analyzer 1f, a through-hole 46 is provided in the optical waveguide circuit 10. The through-hole 46 extends from the sample support area 19 to the main surface 10b and penetrates the optical waveguide circuit 10. The through-hole 46 is located inside the waveguide-type ring resonator 12. The excitation light 24 passes through the through-hole 46 and is radiated onto the sample 21. In the present embodiment, in a plan view of the main surface 10a, the size of the sample 21 is larger than the size of the through-hole 46.

[0093] The non-invasive substance analyzer 1f of the present embodiment further has the following effects in addition to the effects of the non-invasive substance analyzer 1 of the first embodiment.

[0094] In the non-invasive substance analyzer 1f of the present embodiment, a through-hole 46 extending from the sample support portion 19 to the second main surface (the main surface 10b) is provided in the optical waveguide circuit 10. The excitation light 24 passes through the through-hole 46 and is radiated onto the sample 21.

[0095] The through-hole 46 through which the excitation light 24 passes is provided in the optical waveguide circuit 10. Therefore, the excitation light 24 is not absorbed by the optical waveguide circuit 10 and thus reaches the sample 21 with stronger light intensity. The absorption heat in the sample 21 increases. Furthermore, the absorption heat in the sample 21 is difficult to escape in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other). The change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes larger. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0096] Even if the optical waveguide circuit 10 (the substrate 15) is made of a material that is opaque to the excitation light 24, the excitation light 24 can be radiated from the main surface 10b side toward the sample 21. This expands the choice of materials for the optical waveguide circuit 10 (the substrate 15) and increases the degree of freedom in arranging the excitation light source 23. Seventh embodiment

[0097] A non-invasive substance analyzer 1g according to a seventh embodiment will be described with reference to the Fig. 17 and Fig. 18. The non-invasive substance analyzer 1g of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1f of the sixth embodiment, but differs mainly in the following points.

[0098] The non-invasive substance analyzer 1g further includes an optical medium 50. The optical medium 50 transmits the excitation light 24. The transmittance of the optical medium 50 with respect to the excitation light 24 is greater than the transmittance of the optical waveguide circuit 10 (the substrate 15) with respect to the excitation light 24. The excitation light 24 passes through the optical medium 50 and is radiated onto the sample 21. When the excitation light 24 is mid-infrared light, the optical medium 50 is made of a material transparent to the mid-infrared light, such as germanium (Ge), zinc selenide (ZnSe), zinc sulfide (ZnS), or chalcogenide glass (SSbSnGe).

[0099] The optical medium 50 seals the through-hole 46. At least a portion of the sample support area 19 is formed by the optical medium 50. The sample 21 can be placed on the optical medium 50. The through-hole 46 is filled with the optical medium 50. The optical medium 50 extends from the sample support area 19 to the main surface 10b. The thermal conductivity of the optical medium 50 is greater than the thermal conductivity of air. Therefore, the absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12 through the optical medium 50. The thermal conductivity of the optical medium 50 can be greater than the thermal conductivity of the cladding layer 14. The thermal conductivity of the optical medium 50 is less than the thermal conductivity of the substrate 15.Therefore, it is difficult for the absorption heat in the sample 21 to escape in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other).

[0100] With reference to Fig. 19, in a modification of the present embodiment, the optical medium 50 extends from the sample support portion 19 to a height of an inner side surface 12a of the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other). In other words, the optical medium 50 faces at least a part of the inner side surface 12a of the waveguide-type ring resonator 12. The optical medium 50 may extend from the sample support portion 19 to a height of a bottom surface 12b of the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10. In other words, the optical medium 50 may face the entire inner side surface 12a of the waveguide-type ring resonator 12. The lower surface 12b of the waveguide-type ring resonator 12 faces the main surface 10b.

[0101] A portion of the through-hole 46 located closer to the main surface 10b than the optical medium 50 is a cavity not filled with the optical medium 50. The excitation light 24 passes through the cavity and the optical medium 50 and is radiated onto the sample 21. The optical medium 50 is separated from the substrate 15, making it difficult for the absorption heat in the sample 21 to escape through the optical medium 50 to the substrate 15. Therefore, the optical medium 50 can be made of a material having a higher thermal conductivity than the cladding layer 14. For example, the optical medium 50 can be made of a material having a thermal conductivity of 10 W / (m·K) or more, such as germanium (Ge), zinc selenide (ZnSe), or zinc sulfide (ZnS). Therefore, the absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12 through the optical medium 50.

[0102] The non-invasive substance analyzer 1g of the present embodiment further has the following effects similar to the effects of the non-invasive substance analyzer 1f of the sixth embodiment.

[0103] The non-invasive substance analyzer 1g of the present embodiment further includes an optical medium 50 that transmits the excitation light 24. The optical medium 50 seals the through-hole 46. The excitation light 24 passes through the optical medium 50 and is radiated onto the sample 21.

[0104] As the excitation light 24 passes through the optical medium 50, it reaches the sample 21 with a higher light intensity. The absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12 through the optical medium 50. The change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes greater. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with greater accuracy.

[0105] The sample 21 can be placed on the optical medium 50. Thus, the substance in the sample 21 or on the surface of the sample 21 can be analyzed even if the size of the sample 21 is smaller than the size of the through-hole 46 or even if the sample 21 is liquid.

[0106] In the non-invasive substance analyzer 1g of the present embodiment, the optical medium 50 extends from the sample support area 19 to the level of the inner side surface 12a of the waveguide-type ring resonator 12. A portion of the through-hole 46 located closer to the second main surface (the main surface 10b) than the optical medium 50 is a cavity not filled with the optical medium 50.

[0107] Since the excitation light 24 is not attenuated in the cavity, the excitation light 24 reaches the sample 21 with a stronger light intensity. The absorption heat in the sample 21 increases. Furthermore, since the thermal conductivity of air in the cavity is low, the cavity makes it difficult for the absorption heat in the sample 21 to escape from the waveguide-type ring resonator 12. Therefore, the change in the intensity of the first light 27a due to an ON / OFF state of the excitation light 24 becomes larger. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy. Eighth embodiment

[0108] A non-invasive substance analyzer 1h according to an eighth embodiment is described with reference to Fig. 20 and Fig.21. The non-invasive substance analyzer 1h of the present embodiment has a configuration similar to that of the non-invasive substance analyzer 1g of the seventh embodiment, but differs mainly in the following points.

[0109] The non-invasive substance analyzer 1h of the present embodiment includes a first optical medium 51 and a second optical medium 52 instead of the optical medium 50. The first optical medium 51 and the second optical medium 52 transmit the excitation light 24. The transmittance of the first optical medium 51 with respect to the excitation light 24 is greater than the transmittance of the optical waveguide circuit 10 (in particular, the substrate 15) with respect to the excitation light 24. The transmittance of the second optical medium 52 with respect to the excitation light 24 is greater than the transmittance of the optical waveguide circuit 10 (in particular, the substrate 15) with respect to the excitation light 24. The first optical medium 51 closes the through-hole 46. The second optical medium 52 closes the through-hole 46. The second optical medium 52 is arranged closer to the sample support area 19 than the first optical medium 51.At least a portion of the sample support area 19 is formed by the second optical medium 52. The sample 21 can be placed on the second optical medium 52. The excitation light 24 passes through the first optical medium 51 and the second optical medium 52 and is radiated onto the sample 21.

[0110] The first optical medium 51 has a lower thermal conductivity than the second optical medium 52. The first optical medium 51 separates the second optical medium 52 from the substrate 15. Therefore, the absorption heat in the sample 21 is difficult to escape in the thickness direction of the optical waveguide circuit 10. For example, the first optical medium 51 may have a thermal conductivity of 5 W / (m·K) or less, or may have a thermal conductivity of 1 W / (m·K) or less. When the excitation light 24 is mid-infrared light, the first optical medium 51 is made of, for example, chalcogenide glass (SSbSnGe).

[0111] The second optical medium 52 has a higher thermal conductivity than the first optical medium 51. Therefore, the absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12 through the second optical medium 52. Since the second optical medium 52 is separated from the substrate 15, it is difficult for the absorption heat in the sample 21 to escape to the substrate 15. Therefore, the second optical medium 52 can be made of a material that has a higher thermal conductivity than the cladding layer 14. For example, the second optical medium 52 can have a thermal conductivity of 10 W / (m·K) or more, or can have a thermal conductivity of 15 W / (m·K) or more. When the excitation light 24 is mid-infrared light, the second optical medium 52 can be made of, for example, germanium (Ge), zinc selenide (ZnSe), or zinc sulfide (ZnS).

[0112] The second optical medium 52 extends from the sample support region 19 to the height of the inner side surface 12a of the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10 (the direction in which the main surface 10a and the main surface 10b face each other). In other words, the second optical medium 52 faces at least a part of the inner side surface 12a of the waveguide-type ring resonator 12. The second optical medium 52 may extend from the sample support region 19 to the height of the bottom surface 12b of the waveguide-type ring resonator 12 in the thickness direction of the optical waveguide circuit 10. In other words, the second optical medium 52 may face the entire inner side surface 12a of the waveguide-type ring resonator 12.

[0113] The non-invasive substance analyzer 1h of the present embodiment further has the following effects similar to the effects of the non-invasive substance analyzer 1g of the seventh embodiment.

[0114] The non-invasive substance analyzer 1h of the present embodiment further includes a first optical medium 51 that transmits the excitation light 24, and a second optical medium 52 that transmits the excitation light 24. The first optical medium 51 seals the through-hole 46. The second optical medium 52 seals the through-hole 46, has a higher thermal conductivity than the first optical medium 51, and is arranged closer to the sample support area 19 than the first optical medium 51. The excitation light 24 passes through the first optical medium 51 and the second optical medium 52 and is radiated onto the sample 21.

[0115] The absorption heat in the sample 21 is efficiently conducted to the waveguide-type ring resonator 12 through the second optical medium 52. However, the first optical medium 51 makes it difficult for the absorption heat in the sample 21 to escape from the waveguide-type ring resonator 12. The change in the intensity of the first light 27a due to the ON / OFF state of the excitation light 24 becomes greater. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0116] The sample 21 can be placed on the second optical medium 52. Thus, the substance in the sample 21 or on the surface of the sample 21 can be analyzed, even if the size of the sample 21 is smaller than the size of the through-hole 46 or even if the sample 21 is liquid.

[0117] In the non-invasive substance analyzer 1h of the present embodiment, the second optical medium 52 extends from the sample support portion 19 to the level of the inner side surface 12a of the waveguide-type ring resonator 12.

[0118] The absorption heat in the sample 21 is more efficiently conducted to the waveguide-type ring resonator 12 through the optical medium 50. Therefore, the change in the intensity of the first light 27a due to an ON / OFF state of the excitation light 24 becomes greater. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0119] In the non-invasive substance analyzer 1h of the present embodiment, the second optical medium 52 extends from the sample support area 19 to the level of the lower surface 12b of the waveguide-type ring resonator 12. The lower surface 12b of the waveguide-type ring resonator 12 faces the second main surface (the main surface 10b).

[0120] The absorption heat in the sample 21 is more efficiently conducted to the waveguide-type ring resonator 12 through the optical medium 50. Therefore, the change in the intensity of the first light 27a due to an ON / OFF state of the excitation light 24 becomes greater. Therefore, the substance in the sample 21 or on the surface of the sample 21 can be analyzed with higher accuracy.

[0121] It should be understood that the first to eighth embodiments disclosed herein are illustrative and not restrictive in all respects. At least two of the first to eighth embodiments disclosed herein may be combined as long as they do not result in a contradiction. The scope of the present disclosure is defined by the claims rather than the foregoing description, and is intended to include all modifications within the spirit and scope of the claims. LIST OF REFERENCE SYMBOLS

[0122] 1, 1b, 1c, 1d, 1e, 1f, 1g, 1h: non-invasive substance analyzer; 10: optical fiber circuit; 10a, 10b: main surface; 11: first optical fiber; 11a, 11b, 13a, 13b: end; 12: waveguide-type ring resonator; 12a: inner side surface; 12b: bottom surface; 13: second optical fiber; 14: cladding layer; 15: substrate; 15a: surface; 15c: recess; 16, 17: terminal portion; 19: sample support portion; 21: sample; 23: excitation light source; 24: excitation light; 26: probe light source; 27: probe light; 27a: first light; 27b: second light; 30, 37: Light intensity detector; 33: Substance analyzer; 40, 42: Temperature controller; 44: Heat insulating element; 46: Through hole; 50: Optical medium; 51: First optical medium; 52: Second optical medium. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2017-519214

[0002]

Claims

[1] Non-invasive substance analyzer comprising: an optical fiber circuit having a first main surface including a sample support area and a second main surface opposite the first main surface; an excitation light source that emits excitation light toward a sample placed on the sample support area; a probe light source that emits probe light; and a first light intensity detector, wherein the optical waveguide circuit includes a first optical waveguide onto which the probe light is incident, a waveguide-type ring resonator optically coupled to the first optical waveguide, and a second optical waveguide optically coupled to the waveguide-type ring resonator, the first light intensity detector is optically coupled to the second optical fiber and detects an intensity of the first light that is part of the probe light and is optically coupled to the second optical fiber. [2] The non-invasive substance analyzer according to claim 1, wherein, in a plan view of the first main surface, the sample support portion is located inside the waveguide-type ring resonator. [3] A non-invasive substance analyzer according to claim 1 or claim 2, further comprising: a substance analysis unit that analyzes a substance in the sample or on a surface of the sample based on the intensity of the first light. [4] A non-invasive substance analyzer according to claim 1 or claim 2, further comprising: a second light intensity detector, wherein the second light intensity detector is optically coupled to the first optical waveguide and detects an intensity of second light that is part of the probe light and propagates in the first optical waveguide without being coupled to the waveguide-type ring resonator. [5] A non-invasive substance analyzer according to claim 4, further comprising: a substance analysis unit that analyzes a substance in the sample or on a surface of the sample based on a difference between the intensity of the first light and the intensity of the second light. [6] The non-invasive substance analyzer of claim 1, further comprising: a temperature controller that controls a temperature of the waveguide-type ring resonator. [7] The non-invasive substance analyzer according to claim 6, wherein, in a plan view of the first main surface, a length of the temperature controller in a circumferential direction of the waveguide type ring resonator is 50% or less of a length of the waveguide type ring resonator in the circumferential direction. [8] A non-invasive substance analyzer according to any one of claims 1 to 5, further comprising: a temperature controller that controls a temperature of the probe light source. [9] A non-invasive substance analyzer according to claim 1, wherein the optical waveguide circuit includes a substrate supporting the waveguide-type ring resonator and a thermal insulation element having a lower thermal conductivity than the substrate, a recess overlapping the waveguide-type ring resonator in a plan view of the first main surface is provided on a surface of the substrate facing the waveguide-type ring resonator, and the recess is filled with the thermal insulation element. [10] A non-invasive substance analyzer according to any one of claims 1 to 9, wherein a through-hole extending from the sample support portion to the second main surface is provided in the optical waveguide circuit, and the excitation light passes through the through-hole and is irradiated onto the sample. [11] A non-invasive substance analyzer according to claim 10, further comprising: an optical medium that allows the excitation light to pass through, wherein the optical medium closes the through hole and the excitation light passes through the optical medium and is radiated onto the sample. [12] Non-invasive substance analyzer according to claim 11, wherein the optical medium extends from the sample support region to a height of an inner surface of the waveguide-type ring resonator and a portion of the through-hole that is closer to the second main surface than the optical medium is a cavity that is not filled with the optical medium. [13] A non-invasive substance analyzer according to claim 10, further comprising: a first optical medium which transmits the excitation light; and a second optical medium that allows the excitation light to pass through, wherein the first optical medium closes the through hole, the second optical medium closes the through-hole, has a higher thermal conductivity than the first optical medium and is arranged closer to the sample support area than the first optical medium and the excitation light passes through the first optical medium and the second optical medium and is radiated onto the sample. [14] A non-invasive substance analyzer according to claim 13, wherein the second optical medium extends from the sample support region to a height of an inner side surface of the waveguide-type ring resonator. [15] Non-invasive substance analyzer according to claim 13, wherein the second optical medium extends from the sample support region to a height of a lower surface of the waveguide-type ring resonator and the lower surface of the waveguide-type ring resonator faces the second main surface. [16] A non-invasive substance analyzer according to any one of claims 1 to 3, wherein the optical fiber circuit includes a first termination portion, the second optical waveguide includes a first end optically coupled to the first light intensity detector and a second end opposite the first end, and the first termination portion is provided at the second end of the second optical waveguide and scatters or absorbs the probe light. [17] Non-invasive substance analyzer according to claim 16, wherein the optical fiber circuit includes a second termination section, the first optical waveguide includes a third end onto which the probe light is incident and a fourth end opposite the third end, and the second termination portion is provided at the fourth end of the first optical waveguide and scatters or absorbs the probe light. [18] A non-invasive substance analyzer according to any one of claims 1 to 17, wherein the waveguide type ring resonator is a silicon waveguide.

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