JP2007263736A - Measuring system using surface plasmon resonance sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring system using a surface plasmon resonance sensor capable of measuring a refractive index to be measured with high resolving power and high sensitivity even if the refractive index is within a wide range by providing constitution that a plurality of sensors are provided to a single chip. <P>SOLUTION: A sensor array is constituted by providing a plurality of the sensor to the signal chip. Fiber arrays 8 are connected to the light waveguide of the sensor array and one of them is connected to a light source to guide light while the other one of them is connected to a detector. A metal thin film and a refractive index adjusting layer 7 are appropriately provided to a sensing part 5. A film thickness and a dielectric constant are adjusted with respect to the metal thin film and the refractive index adjusting layer 7 at every sensor to adjust the manufacturing condition of the light waveguide. When lights of the same wavelength are thrown the respective sensors (respective channels), operation different in refractive index causing resonance is obtained. In the signal chip, the wavelength related to measurement becomes a narrow range in each of the channels and the measurement of the refractive index can be set to a wide range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a measurement system using a surface plasmon resonance sensor, and more specifically, the surface plasmon resonance sensor includes a plurality of sensors, and the measurement system such as a refractive index has an enlarged measurement range, sensitivity, resolution, and the like. It is related with the improvement of the performance side.

  FIG. 1 shows a conventional example of a surface plasmon resonance sensor and is a configuration diagram of a prism type SPR sensor. SPR is an abbreviation for Surface Plasmon Resonance.

  The prism type SPR sensor has a configuration in which the metal thin film 4 is formed on one surface of the prism 100, the light source 102 is disposed on the other surface side of the prism 100, and the detector 103 is disposed on the other surface side. 4, the substance 6 to be measured is placed thereon, the light from the light source 102 is incident thereon, and the reflected light emitted from the other surface is taken into the detector 103.

  The light from the light source 102 is incident at an angle that totally reflects the surface of the metal thin film 4. On the reflecting surface, an evanescent wave oozes out in the substance 6 to be measured, and its wave number kev is determined by the wave number and incident angle of the incident light in free space. Surface plasmons are generated on the surface of the metal thin film 4, and the wave number ksp is determined by the refractive index of the substance 6 to be measured and the dielectric constant of the metal thin film 4. When the wave number kev of the evanescent wave and the wave number ksp of the surface plasmon wave match, the energy of the evanescent wave is used to excite the surface plasmon wave, and the intensity of the reflected light decreases. In other words, the reflected wave intensity is monitored by changing the incident angle, the reflected light intensity is monitored while changing the wavelength of the incident light, or the spectral intensity of the reflected light is monitored by incident white light. Thus, the refractive index of the substance 6 to be measured can be known.

As shown in FIG. 2, when a dielectric thin film 7 is provided on the metal thin film 4 and a substance to be measured 6 is brought into contact therewith, the resonance condition is different from that when the dielectric thin film 7 is not present. Alternatively, the resonance condition can also be changed by changing the material (dielectric constant) and film thickness of the dielectric thin film 7. The material of the dielectric thin film 7 is required to be transparent (low absorption) at the wavelength of light used for measurement. Specifically, Ta ₂ O ₅ , TiO ₂ , TiN, Si or the like is used. Hereinafter, for the purpose of changing the resonance condition, the film layer of the dielectric thin film 7 applied on the metal thin film 4 is referred to as a refractive index adjusting layer.

  FIG. 3 shows another example of a conventional surface plasmon resonance sensor, and is a perspective view (a) and a sectional view (b) of a waveguide type SPR sensor. In the waveguide type, an optical waveguide 3 having a core 1 and a low refractive index medium (cladding 2) surrounding the core 1 and confining and propagating light incident on the core 1 is provided. A part is opened, a metal thin film 4 is applied thereto to form a sensing part 5, and a substance 6 to be measured is brought into contact with the sensing part (opening surface).

  The clad 2 does not need to be completely opened, and may be any thickness as long as an evanescent wave can be generated in the substance 6 to be measured. The light propagating through the core 1 oozes out as an evanescent wave to the substance 6 to be measured in the sensing unit 5, and the wave number kev is determined by the wave number of the light propagating through the optical waveguide 3. Surface plasmons are generated on the surface of the metal thin film 4, and the wave number ksp is determined by the refractive index of the substance 6 to be measured and the dielectric constant of the metal thin film 4. When the wave number kev of the evanescent wave coincides with the wave number ksp of the surface plasmon wave, the energy of the evanescent wave is used to excite the surface plasmon wave, and the intensity of the emitted light decreases. That is, the refractive index of the substance 6 to be measured can be measured from the relationship between the intensity of the emitted light and the wavelength.

  Specifically, the intensity of the emitted light is monitored while changing the wavelength of the incident light, or white light is incident and the emitted light is dispersed to obtain a resonance wavelength to know the refractive index of the substance 6 to be measured ( In the following, this will be referred to as spectroscopy). In addition, there is a method of specifying the refractive index of the substance 6 to be measured from the intensity of the emitted light from the sensor by making use of the fact that the resonance wavelength changes depending on the refractive index of the substance 6 to be measured (hereinafter referred to as “resonance wavelength”). Let's call it the strength method).

  Also in the waveguide type, as in the prism type, the resonance condition can be changed even with light of the same wavelength by providing a refractive index adjustment layer. In addition, the resonance condition varies depending on the manufacturing conditions of the optical waveguide 3. For example, changing the effective refractive index of the optical waveguide 3 changes the wavelength of the light propagating through the core 1, so that the resonance condition changes.

  However, such conventional SPR sensors have the following problems. The prism-type SPR sensor requires a mechanism for changing the incident angle, and does not function unless components such as the prism 100 and the lens are properly assembled, making it difficult to reduce the size and limiting the cost reduction.

  The waveguide type SPR sensor can reduce the size of the sensing unit 5, but if it is intended to measure a wide range of refractive index by spectroscopy, the wavelength range of the measurement light becomes wide. This is because, in the case of a linear optical waveguide 3, particularly a single mode optical waveguide, the wavelength range in which the optical waveguide 3 can be properly propagated is limited in principle, so a single sensor measures a wide range of refractive indexes. Can not do it.

  In addition, the intensity method using the waveguide type SPR sensor does not require a spectroscopic optical system, so it seems that the cost can be reduced and the size can be reduced. However, since the measurement is performed using monochromatic light, the refractive index range is within the resonance characteristic curve width range. It will be limited. And because sensor output fluctuates due to factors such as light source intensity fluctuation, sensor sensitivity fluctuation, and connector connection loss fluctuation, a mechanism that stabilizes the light source and sensor is required to configure an accurate measurement system. The benefits of cost reduction and miniaturization are not always expected.

  In any sensor, by selecting the film thickness and dielectric constant of the metal thin film 4 and the refractive index adjustment layer 7 in the sensing part, the half-value width of the resonance characteristic curve can be widened, and the range of the refractive index is limited to some extent. Can also be expanded. However, in that case, resolution and sensitivity are lowered.

  The present invention solves the above-described problems. The purpose of the present invention is to provide a structure in which a plurality of sensors are provided on a single chip. An object of the present invention is to provide a measurement system using a surface plasmon resonance sensor that can be reduced in cost and cost.

  In order to achieve the above-described object, a measurement system using a surface plasmon resonance sensor according to the present invention provides a metal thin film to an optical waveguide that includes a core and a clad covering the core and propagates light incident on the core. The surface plasmon resonance sensor that can measure the refractive index by surface plasmon resonance is configured for the medium in contact with the metal thin film, and the evanescent light of the light propagating through the optical waveguide is generated in the medium in contact with the metal thin film. The surface plasmon resonance sensor is a sensor array in which a plurality are arranged and integrated, and for each sensor, the metal thin film is set to have either a dielectric constant or a film thickness different, or both the dielectric constant and the film thickness are set differently. .

  In addition, a metal thin film is applied to an optical waveguide that is composed of a core and a clad covering the core and propagates light incident on the core, and a dielectric thin film is applied on the metal thin film to form a thin film having two layers. A surface plasmon resonance sensor that can measure the refractive index by surface plasmon resonance is configured for the medium in contact with the dielectric thin film, and the evanescent light propagating through the waveguide is generated in the medium in contact with the dielectric thin film. The surface plasmon resonance sensor is a sensor array in which a plurality of the surface plasmon resonance sensors are arranged and integrated, and for each sensor, one or more of the film thickness or dielectric constant of the metal thin film or the dielectric constant or film thickness of the dielectric thin film is made different. It is good also as a setting. .

  In addition, the optical waveguide may have a configuration in which a plurality of different manufacturing conditions are arranged, or a configuration in which a plurality of optical waveguides having different effective refractive indexes are arranged.

  Further, a fiber array can be connected to the sensor array, and the arrangement pitch of the sensing units in the sensor array can be set to be narrower than the arrangement pitch of the optical paths in the fiber array. In addition, a power splitter may be connected to the sensor array, and the light from the light source may be branched by the power splitter and supplied to each sensor.

  The power splitter is an optical waveguide power splitter, and the power splitter and the sensor array are preferably formed integrally on the same chip. In addition, at least one calibration sensor is provided in the sensor array, the calibration sensor is configured not to cause surface plasmon resonance with the substance to be measured, and output fluctuation obtained by monitoring the output of the calibration sensor. The output of the other sensor can be calibrated according to the data.

  In addition, the calibration sensor has a structure that causes surface plasmon resonance at the measurement wavelength and does not react with the substance to be measured, and for the calibration sensor, monitors the refractive index of the dielectric thin film in the sensing section to change with temperature. The refractive index of the substance to be measured may be calibrated according to the temperature characteristic data obtained in this way.

  Further, the first calibration sensor causes surface plasmon resonance at the measurement wavelength, and the resonance wavelength exists on the shorter wavelength side than the measurement wavelength, and the second calibration sensor causes surface plasmon resonance at the measurement wavelength. The resonance wavelength is present on the longer wavelength side than the measurement wavelength, the first calibration sensor and the second calibration sensor are configured not to react with the substance to be measured, and the outputs of these calibration sensors are monitored. The output of another sensor may be calibrated in accordance with the output fluctuation data.

  With this configuration, in the present invention, the surface plasmon resonance sensor is configured as an integrated sensor array in which a plurality of surface plasmon resonance sensors are arranged, and for each sensor, the manufacturing conditions of the optical waveguide, the metal thin film of the sensing unit, or the refractive index adjustment layer The material (dielectric constant) and film thickness are changed. For this reason, when light of the same wavelength is incident on each sensor (each channel), the refractive index at which resonance occurs is different. Therefore, in a single chip, the measurement wavelength can be narrow in each channel, and the refractive index can be measured in a wide range.

  Moreover, the optical waveguide can be arranged in a line by bringing the sensing portions of the respective channels close to each other. For this reason, a sensor array can be reduced in size and even if a to-be-measured substance is a trace amount, it can measure simultaneously with all the channels.

  In the measurement system using the surface plasmon resonance sensor according to the present invention, the surface plasmon resonance sensor is configured as a sensor array in which a plurality of the surface plasmon resonance sensors are arranged and integrated. Since the refractive index is adjusted and the optical waveguide fabrication conditions are adjusted, measurement can be performed with high resolution and high sensitivity even in a wide range of refractive indexes requiring measurement. As a result, downsizing and cost reduction can be achieved.

  Hereinafter, preferred embodiments of the present invention will be described.

* Basic Configuration with Multiple Sensors FIG. 4 is a configuration diagram showing a basic configuration example 1 of the surface plasmon resonance sensor according to the present invention. The surface plasmon resonance sensor shown in the figure is a three-channel configuration example, and has three optical waveguides on a single chip. The optical waveguide fabrication conditions, the metal thin film of the sensing unit 5 or the refractive index adjustment for each channel The material (dielectric constant) and film thickness of the layer are changed. For this reason, when light of the same wavelength is incident on each channel, the refractive indexes at which resonance occurs are different, and the operation is as shown in FIG. For example, when the refractive index of the substance 6 to be measured is point A, the channel 1 resonates and the output decreases, and the other channels 2 and 3 output the light source intensity as it is. When the refractive index of the substance to be measured is point B, the channel 2 resonates and the output decreases, and the other channels 1 and 3 output the light source intensity as it is. Thereby, in a single chip, the measurement wavelength can be narrow in each channel, and the refractive index can be measured in a wide range.

  Moreover, since the optical waveguide is formed in a linear shape, the sensing portions 5 of the respective channels can be arranged close to each other. For this reason, a sensor array can be reduced in size and even if the to-be-measured substance 6 is a trace amount, it can measure simultaneously by all the channels. Then, it may be considered that there is almost no variation in temperature of the substance 6 to be measured for all channels, and errors due to the variation in temperature can be reduced.

* Manufacture of Waveguide SPR Sensor FIGS. 6A and 6B are perspective views for explaining a method of manufacturing a waveguide SPR sensor. For manufacturing the sensor chip, a general manufacturing technique for manufacturing the optical waveguide can be applied, and there is no particular difficulty in manufacturing, and the manufacturing can be easily performed. In the figure, manufacturing for one channel is shown.

  First, as a method of forming the core 1 portion with respect to the clad 2, a glass material or resin is deposited and then etched to form the core 1, and ion exchange that makes the glass material have a refractive index is ion-exchanged. Method of injecting by method, method of forming by irradiating with UV light after laminating photosensitive resin, developing, method of forming by pressing mold after glass material or resin is deposited and curing (transfer method) and so on.

  As a method for forming the cladding 2 as the upper layer and the opening as the sensing portion 5, a method of forming an opening as the sensing portion 5 by depositing a glass material or a resin and depositing the glass material or resin, and UV sensing as the cladding 2. A method of forming an opening by irradiating with UV light after laminating a resin and developing it, and a method of forming an opening by pressing a mold in a state where the resin is fluid after laminating a resin material and solidifying the mold There is a method of bonding a glass plate or a resin plate having an opening.

  Further, as shown in FIG. 6A, the metal thin film 4 provided in the sensing unit 5 may be formed before forming the upper clad 2, and as shown in FIG. There is a method of forming a film after forming the cladding 2 and the opening of the layer.

* Structural Example of Refractive Index Adjusting Layer In the present invention, a plurality of optical waveguides are formed by arranging a plurality of optical waveguides. That is, the waveguide type SPR sensor shown in FIG. 7 has a three-channel configuration in which three optical waveguides are linearly arranged to form a single chip. A fiber array 8 is connected to the optical waveguide of the sensor array. One is connected to a light source to be an input side for guiding monochromatic light, and the other is connected to a detector to be an output side. The optical waveguide and the metal thin film 4 are all manufactured under the same conditions, but the refractive index adjusting layer 7 provided on the metal thin film 4 has a different thickness in each channel. For example, the refractive index adjustment layer 7 is not formed in the sensing unit 5 in the first channel, the refractive index adjustment layer 7 is formed in a thickness of 60 nm in the second channel, and the refractive index adjustment layer 7 is formed in a thickness of 120 nm in the third channel. To form. The thickness of the metal thin film 4 is, for example, about 10 nm to 80 nm.

  Here, when monochromatic light having the same wavelength is incident on each channel, the intensity change of the output light can be obtained in each channel with respect to the refractive index (concentration) of the substance to be measured, as shown in FIG. . At this time, the sensing unit 5 of each channel can measure only a narrow range of refractive index, but a wide range of measurements can be performed by arranging a large number of arrays.

  Here, the film thickness of the refractive index adjustment layer 7 is changed for each channel, but other configurations include the dielectric constant and film thickness of the metal thin film 4, the dielectric constant of the refractive index adjustment layer 7, and the production of the optical waveguide. By changing the conditions, the resonance conditions can be changed for each channel.

* Configuration Example of Sensor Array FIGS. 9 to 12 are configuration diagrams showing configuration examples 3 to 6 of the sensor array according to the present invention. These use an optical waveguide type power splitter 9 to supply light to each channel of the sensor array.

  The power splitter 9 is joined to the sensor array directly as shown in FIG. 9, or the fiber array 8 is joined between them as shown in FIG. 10, or as shown in FIG. As described above, a configuration is adopted in which both the sensor array and the power splitter 9 are integrally formed on the same chip.

  Further, as shown in FIG. 12, the arrangement pitch of the sensing units 5 may be set narrow. In this case, the sensor array integrated with the power splitter 9 is provided with an optical waveguide for pitch conversion, and the sensing unit 5 is arranged so as to be very close to each other, and the optical waveguide below the part does not interfere optically. The distance may be close. As a result, measurement can be performed even with a smaller amount of sample of, for example, 10 nl or less.

  By using the power splitter 9, only one light source is required, and the cost of the measuring apparatus can be reduced and the size can be reduced.

* Reflective SPR Sensor FIG. 13 is a configuration diagram showing a measuring apparatus using a reflective SPR sensor. The above-described waveguide SPR sensor can be a reflective sensor array in which the reflective film 10 is provided on the output side. The main body of the measuring device is configured by sequentially connecting the LD light source 11, the isolator 13, the optical fiber 12, the power splitter 9, and the photodiode array 14, and is connected to the reflective sensor array via the tape fiber 15. .

* Elimination of fluctuation effects The intensity method eliminates the need for a spectroscopic optical system, so the cost of the measuring apparatus can be reduced and the size can be reduced. However, there is a problem that the sensor output fluctuates due to variations in the intensity and wavelength of the light source, fluctuations in the sensitivity of the detector, variations in connection loss in the connector and the like. That is, a means for removing intensity changes caused by factors other than SPR is required, and for example, a temperature adjusting device using a Peltier element, light source intensity monitoring, and the like are required.

  Therefore, as shown in FIG. 14, at least one of the optical waveguides in the sensor array is not provided with the sensing unit 5, and the configuration in which the incident light is directly propagated to the detector is adopted. Thereby, the fluctuation | variation in a light source, a detector, etc. can be monitored, and the intensity | strength change by factors other than SPR can be removed. Therefore, the cost and size of the measuring device can be reduced.

  FIG. 15 shows a configuration example 8 in which the influence of the wavelength variation of the light source is removed, and FIG. 16 is a graph for explaining the variation of the measurement wavelength. The sensing unit 5 of the first channel and the second channel in the sensor array is provided with a dielectric material that resonates at the measurement wavelength, and by appropriately selecting the material (refractive index) of the dielectric material, the first channel The resonance wavelength of the second channel is set slightly shorter than the measurement wavelength, and the resonance wavelength of the second channel is set slightly longer than the measurement wavelength. Further, the third channel is provided with a substance (referred to as a temperature measuring material) having a large temperature dependence of the refractive index, and the temperature measuring material is selected so as to resonate at the measurement wavelength. Is used. These first to third channels have a structure that does not resonate with the substance to be measured.

  When the wave quality of the light source fluctuates to the longer wavelength side, the intensity of the first channel increases, but the intensity of the second channel 2 decreases. If the intensity varies, both the first channel and the second channel vary in the same direction. However, if the wavelength varies, the effects vary due to the intensity variation and the wavelength variation.

  When the substance to be measured is a liquid, the temperature dependence of the refractive index is not small, and a mechanism for stabilizing the temperature of the substance to be measured and the sensing unit 5 is provided, or the temperature of the liquid is monitored to perform temperature calibration. For monitoring the liquid temperature, it is desirable to provide a temperature sensor in the vicinity of the SPR sensor. For example, there is a method of measuring the temperature by attaching a resistor or the like to the SPR sensor and electrically monitoring the change in the resistance value. In such a case, both the optical fiber and the electrical wiring are required for the SPR sensor. In particular, in the configuration in which the sensor array is remotely measured away from the measuring apparatus main body, there is a problem that the cost is increased due to the electrical wiring.

  However, in the present invention, the third channel is provided with a substance (temperature measuring material) having a large temperature dependence of the refractive index, so that the refractive index of the temperature measuring material changes according to the temperature of the substance to be measured, The operation of the third channel is changed, and temperature measurement can be performed. For this reason, the temperature can be monitored only with the optical fiber wiring, and the cost can be reduced.

It is a block diagram of a prism type SPR sensor, showing an example of a conventional surface plasmon resonance sensor. It is a block diagram which shows the other example of a prism type SPR sensor. The other example of the conventional surface plasmon resonance sensor is shown, The perspective view (a) and sectional drawing (b) of a waveguide type | mold SPR sensor. It is a block diagram which shows the basic structural example 1 of the surface plasmon resonance sensor which concerns on this invention. It is a graph which shows the relationship between the refractive index of a to-be-measured substance, and the output of each channel. It is a perspective view explaining the manufacturing method of a waveguide type SPR sensor. It is a block diagram which shows the structural example 2 provided with a refractive index adjustment layer in a waveguide type | mold SPR sensor. It is a graph which shows the relationship between the refractive index of a to-be-measured substance, and the output of each channel. It is a block diagram which shows the structural example 3 of the sensor array which concerns on this invention. It is a block diagram which shows the structural example 4 of the sensor array which concerns on this invention. It is a block diagram which shows the structural example 5 of the sensor array which concerns on this invention. It is a block diagram which shows the structural example 6 of the sensor array which concerns on this invention. It is a block diagram which shows the measuring apparatus using a reflection type SPR sensor. It is a block diagram of the structural example 7 which removed the influence of a fluctuation | variation. It is a block diagram of the structural example 8 which removed the influence of the wavelength variation of a light source. It is a graph explaining the fluctuation | variation of a measurement wavelength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Core 2 Clad 3 Optical waveguide 4 Metal thin film 5 Sensing part 6 Measured substance 7 Dielectric thin film (refractive index adjustment layer)
8 Fiber array 9 Power splitter 10 Reflective film 11 LD light source 12 Optical fiber 13 Isolator 14 Photodiode array 15 Tape fiber

Claims (11)

A metal thin film is applied to an optical waveguide that is composed of a core and a clad covering the core and propagates light incident on the core,
The evanescent light of the light propagating through the optical waveguide is generated in a medium in contact with the metal thin film,
Constructing a surface plasmon resonance sensor capable of measuring the refractive index by surface plasmon resonance for the medium in contact with the metal thin film,
The surface plasmon resonance sensor is a sensor array in which a plurality are arranged and integrated,
A measuring system using a surface plasmon resonance sensor, wherein each metal thin film has a dielectric constant or a film thickness different from each other, or both the dielectric constant and the film thickness are set differently. A metal thin film is applied to an optical waveguide consisting of a core and a clad covering the core and propagating light incident on the core, and a dielectric thin film is applied on the metal thin film to form two thin films.
The evanescent light of the light propagating through the optical waveguide is generated in a medium in contact with the dielectric thin film,
Constructing a surface plasmon resonance sensor capable of measuring the refractive index by surface plasmon resonance for the medium in contact with the dielectric thin film,
The surface plasmon resonance sensor is a sensor array in which a plurality of the surface plasmon resonance sensors are arranged and integrated, and for each sensor, at least one of the film thickness or dielectric constant of the metal thin film or the dielectric constant or film thickness of the dielectric thin film is obtained. A measurement system using a surface plasmon resonance sensor, characterized in that the setting is different.   The measurement system using the surface plasmon resonance sensor according to claim 1, wherein the optical waveguide has a configuration in which a plurality of different manufacturing conditions are arranged.   The measurement system using the surface plasmon resonance sensor according to claim 1, wherein the optical waveguide has a configuration in which a plurality of different effective refractive indexes are arranged.   The fiber array is connected to the sensor array, and the arrangement pitch of the sensing units in the sensor array is set to be narrower than the arrangement pitch of the optical paths in the fiber array. A measurement system using the surface plasmon resonance sensor according to item 1.   6. The surface plasmon resonance sensor according to claim 1, wherein a power splitter is connected to the sensor array, and light from a light source is branched by the power splitter and supplied to each sensor. Measuring system using.   The measurement system using a surface plasmon resonance sensor according to claim 6, wherein the power splitter is an optical waveguide power splitter.   The measurement system using a surface plasmon resonance sensor according to claim 6, wherein the power splitter and the sensor array are integrally formed on the same chip.   The sensor array is provided with at least one calibration sensor, the calibration sensor does not cause surface plasmon resonance with the substance to be measured, and the output fluctuation obtained by monitoring the output of the calibration sensor The measurement system using the surface plasmon resonance sensor according to any one of claims 1 to 8, wherein the output of another sensor is calibrated according to the data.   The calibration sensor is configured to cause surface plasmon resonance at the measurement wavelength and not to react with the substance to be measured, and for the calibration sensor, monitor that the refractive index of the dielectric thin film of the sensing unit changes with temperature. The measurement system using a surface plasmon resonance sensor according to claim 9, wherein the refractive index of the substance to be measured is calibrated according to the obtained temperature characteristic data. The first calibration sensor causes surface plasmon resonance at the measurement wavelength, and the resonance wavelength is present on the shorter wavelength side than the measurement wavelength, and the second calibration sensor causes surface plasmon resonance at the measurement wavelength. And the resonance wavelength is configured to exist on the longer wavelength side than the measurement wavelength,
The first calibration sensor and the second calibration sensor are configured not to react with the substance to be measured, and the outputs of other sensors are calibrated in accordance with output fluctuation data obtained by monitoring the outputs of the calibration sensors. The measurement system using the surface plasmon resonance sensor according to claim 9 or 10.

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