WO2012102350A1 - 表面プラズモンセンサ、及び屈折率の測定方法 - Google Patents
表面プラズモンセンサ、及び屈折率の測定方法 Download PDFInfo
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- WO2012102350A1 WO2012102350A1 PCT/JP2012/051707 JP2012051707W WO2012102350A1 WO 2012102350 A1 WO2012102350 A1 WO 2012102350A1 JP 2012051707 W JP2012051707 W JP 2012051707W WO 2012102350 A1 WO2012102350 A1 WO 2012102350A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
- G01N21/4133—Refractometers, e.g. differential
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/21—Polarisation-affecting properties
- G01N21/211—Ellipsometry
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/41—Refractivity; Phase-affecting properties, e.g. optical path length
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/55—Specular reflectivity
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/55—Specular reflectivity
- G01N21/552—Attenuated total reflection
- G01N21/553—Attenuated total reflection and using surface plasmons
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/008—Surface plasmon devices
Definitions
- the present invention relates to a surface plasmon sensor and a refractive index measurement method using the surface plasmon sensor.
- a surface plasmon sensor is known as a sensor for optically measuring the refractive index of a liquid or the like.
- the incident angle characteristics (absorption curve) of the reflectance ⁇ when the incident light of wavelength ⁇ is irradiated on the metal surface, the reflectance ⁇ decreases rapidly at a specific incident angle (hereinafter referred to as the absorption angle ⁇ sp ).
- This phenomenon is called plasmon resonance absorption and is caused by electromagnetic wave coupling between incident light and surface plasmons existing on the metal surface.
- the reflected light is reflected. Strength decreases.
- the surface plasmon sensor is a sensor that measures the refractive index of a sample such as a liquid using plasmon resonance absorption.
- Some surface plasmon sensors have a prism disposed on a metal surface, and others have a periodic structure in which grooves are cut at equal intervals on a metal surface as disclosed in Patent Document 1, for example.
- the surface plasmon sensor, pre refractive index n s is to previously obtain the absorption angle theta sp known reference material, the difference ⁇ between the absorption angle theta sp absorption angle theta 'sp and the reference material sample measured refractive index n
- the absorption angle ⁇ sp is an angle at which the reflectance ⁇ decreases rapidly. Therefore, the minimum point must be detected to measure the absorption angle ⁇ sp , and the measurement is complicated. there were.
- the present invention has been made in view of the above points, and provides a surface plasmon sensor capable of easily measuring a refractive index and a method for measuring a refractive index.
- a surface plasmon sensor includes a reflector having a metal layer having a periodic structure, a sample disposed thereon, a light source that irradiates the reflector with incident light, and the reflector.
- a light receiving unit that receives the reflected light reflected, and a measurement unit that measures the refractive index of the sample based on phase difference information of two types of waves having different polarization directions included in the reflected light that is transmitted through and reflected by the sample. It is characterized by providing.
- the refractive index measurement method is a refractive index measurement method using a surface plasmon sensor that measures the refractive index of a sample disposed on a reflector having a metal layer having a periodic structure.
- the step of irradiating the reflecting plate with incident light, the step of receiving the reflected light reflected by the reflecting plate with a light receiving unit, and the two types of waves having different polarization directions included in the reflected light received by the light receiving unit Measuring the refractive index of the sample based on phase information.
- the refractive index can be easily measured.
- FIG. 1 is a schematic diagram of a surface plasmon sensor according to a first embodiment of the present invention.
- 1 is a schematic diagram of a surface plasmon sensor according to a first embodiment of the present invention.
- variation of the ellipticity of the reflected light which concerns on 1st Embodiment of this invention The figure which shows the phase of the reflected light which concerns on 1st Embodiment of this invention.
- Schematic of the surface plasmon sensor which concerns on 2nd Embodiment of this invention Schematic of the surface plasmon sensor which concerns on 3rd Embodiment of this invention.
- variation of the ellipticity which concerns on 3rd Embodiment of this invention The figure which shows the azimuth angle characteristic of the ellipticity which concerns on 3rd Embodiment of this invention. Schematic of the surface plasmon sensor which concerns on 4th Embodiment of this invention. The figure explaining the measuring method of the fluctuation
- strength characteristic which concerns on 8th Embodiment of this invention The figure explaining the measuring method of the received light intensity which concerns on 8th Embodiment of this invention.
- FIG. 1 is a diagram showing an outline of a surface plasmon sensor 1 according to the present embodiment.
- a surface plasmon sensor 1 in FIG. 1 includes a reflecting plate 11 having a metal layer 10 having a periodic structure, a light source 12 that irradiates incident light on the reflecting plate 11, and a light receiving unit 13 that receives reflected light reflected by the reflecting plate. And a measuring unit 14 that measures the refractive index n of the sample placed on the reflecting plate 11 from the fluctuation of the ellipticity of the reflected light.
- the reflecting plate 11 includes a substrate 15 such as silicon and a metal layer 10 such as aluminum laminated on the substrate 15.
- FIG. 2 is a diagram illustrating an example of the metal layer 10.
- irregularities are periodically formed at intervals d that are about the wavelength of light.
- the metal layer 10 has a periodic structure with a period d.
- a direction in which the uneven shape is repeatedly formed is referred to as a periodic direction.
- the periodic structure is formed on the surface of the metal layer 10 that is not in contact with the substrate 15, and the irregular shape is periodically formed in one direction (the x direction in FIG. 2A).
- the formed periodic structure is called a one-dimensional periodic structure.
- the periodic direction is the x direction.
- a periodic structure is formed on the surface of the metal layer 10 that is not in contact with the substrate 15 and is periodically uneven in two directions (x and y directions in FIG. 2B).
- the periodic structure in which the shape is formed is called a two-dimensional periodic structure.
- the periodic directions are the x direction and the y direction.
- the periodic structure in which the periodic structure is formed on both the surface in contact with the surface 15 and the surface facing the surface 15 and the concavo-convex shape is periodically formed in one direction is a one-dimensional thin film. It is called a periodic structure. In this case, the periodic direction is the x direction.
- the substrate of the metal layer 10 is used.
- the periodic structure is formed on both the surface in contact with the surface 15 and the surface opposite to the surface, and the periodic structure in which irregularities are periodically formed in two directions (x and y directions in FIG. 2D). This is called a dimensional thin film periodic structure.
- the periodic directions are the x direction and the y direction.
- the periodic structure is formed on both surfaces of the metal layer 10, but the periodic structure may be formed only on one surface facing the substrate 15.
- a plurality of periodic structures can be formed on the surface of the metal layer 10 depending on the direction in which the uneven shape is repeatedly formed.
- the metal layer 10 of the present embodiment may have any of the above-described periodic structures, but here, it will be described as having a one-dimensional periodic structure with the x direction as the periodic direction.
- the reflecting plate 11 is referred to as a periodic direction (x direction) of the metal layer 10 and a surface S1 on which incident light emitted from the light source 12 is incident (hereinafter referred to as an incident surface S1. Details will be described later. ) And are arranged obliquely so as not to be orthogonal to each other. In this way, the arrangement of the reflecting plate 11 so that the incident surface S1 and the periodic direction are not orthogonal is called a conical mount. An angle formed by the incident surface S1 and the periodic direction is referred to as an azimuth angle ⁇ .
- the reflector 11 of the present embodiment is arranged so that ⁇ ⁇ 0 ° and 90 °.
- the wave number vectors of incident light and zero-order diffracted light (hereinafter referred to as reflected light) exist in the incident plane.
- a sample 16 to be measured for the refractive index n a sample 16 to be measured for the refractive index n, a reference material to be a reference for measuring the refractive index n of the sample 16, and the like are arranged.
- the light source 12 is composed of a light receiving element such as a semiconductor laser or a light emitting diode. Incident light having p waves is emitted from the light source 12.
- the light source 12 irradiates incident light while changing the angle ⁇ (hereinafter referred to as incident angle ⁇ ; see FIG. 3) for irradiating incident light.
- the light source 12 includes a driving device (not shown) necessary for changing the incident angle ⁇ .
- the incident angle may be optically changed by using, for example, a laser diode array.
- the light receiving unit 13 is configured by, for example, a photodiode.
- the light receiving unit 13 receives reflected light having p waves and s waves.
- the light receiving unit 13 includes a driving device for receiving reflected light in conjunction with fluctuations in the incident angle ⁇ of incident light.
- the light receiving unit 13 may also optically change the reflection angle of the reflected light from the light receiving unit 13 by using a photodiode array.
- the measuring unit 14 measures the ellipticity of the reflected light received by the light receiving unit 13 and measures the variation of the ellipticity.
- the measurement unit 14 measures an incident angle ⁇ 0 (hereinafter referred to as an absorption angle ⁇ 0 ) at which the ellipticity is zero from the measured variation in ellipticity.
- the refractive index n of the sample 16 is measured.
- the reflected light received by the light receiving unit 13 will be described with reference to FIG.
- the reflected light is divided into a p-wave component parallel to the incident surface S1 and a vertical s-wave component.
- the electric field vector of the light appears to rotate in an elliptical shape as shown in FIG. 4B according to the phase difference ⁇ between the p wave and the s wave.
- the angle formed by the long axis of the ellipse formed by the electric field vector of the light with respect to the x direction is referred to as an ellipse tilt angle ⁇ .
- phase difference ⁇ between the p wave and the s wave is smaller than zero, that is, when the s wave is delayed as compared with the p wave, the light turns left in an elliptical shape as viewed from the traveling direction, as shown in FIG. ing. This is called left elliptical polarization. At this time, the ellipticity tan ⁇ is smaller than zero.
- phase difference ⁇ between the p wave and the s wave is zero, that is, the phases of the p wave and the s wave are the same, the light vibrates linearly as seen from the traveling direction, as shown in FIG. This is called linearly polarized light.
- the ellipticity tan ⁇ at this time is zero.
- phase difference ⁇ between the p wave and the s wave is greater than zero, that is, when the s wave is ahead of the p wave, as shown in FIG. It is turning. This is called right elliptical polarization. At this time, the ellipticity tan ⁇ is larger than zero.
- the ellipticity tan ⁇ of the reflected light depends on the phase of the p wave and the s wave. Therefore, the phase relationship between the p wave and the s wave can be known by measuring the ellipticity tan ⁇ of the reflected light with the measuring unit 14.
- the ellipticity of the sample 16 a method for measuring the fluctuation of the ellipticity of the reflected light (hereinafter referred to as the ellipticity of the sample 16) when the sample 16 is arranged on the reflecting plate 11 will be described with reference to FIG.
- the variation of the ellipticity of the sample 16 when the incident angle ⁇ of the incident light is changed is measured.
- a sample 16 is placed on the reflecting plate 11 (S101), and incident light having an incident angle ⁇ and a wavelength ⁇ is irradiated from the light source 12 (S102).
- the light source 12 emits p-wave incident light.
- the light receiving unit 13 receives light (reflected light) of incident light reflected by the reflecting plate 11 via the sample 16 (S103).
- the measurement unit 14 measures the ellipticity of the reflected light from the reflected light (S104).
- the light source 12 changes the incident angle ⁇ of the incident light to be irradiated to ⁇ + ⁇ (S105).
- the process returns to step S102.
- the ellipticity tan ⁇ is measured in the entire range of the incident angle ⁇ to be measured (Yes in S106)
- the measurement of the ellipticity variation of the sample 16 is finished.
- FIG. 8 shows a simulation result of the variation of the ellipticity tan ⁇ at each incident angle ⁇ measured by the measurement unit 14.
- FIG. 8 is a diagram showing a tan ⁇ - ⁇ characteristic curve of air, which is the sample 16, measured according to the ellipticity variation measurement flowchart of FIG.
- a holographic aluminum lattice is used as the reflecting plate 11.
- the wavelength ⁇ 670 nm
- the incident angle ⁇ is in the range of 3 ° ⁇ ⁇ 15 °. It was changed with.
- the tan ⁇ - ⁇ characteristic curve changes from positive to negative before and after the absorption angle ⁇ 0 where the ellipticity tan ⁇ becomes zero.
- FIG. 9 shows the phases ⁇ p and ⁇ s and the phase difference ⁇ at each incident angle ⁇ measured by the measurement unit 14.
- the simulation results are shown.
- air is used as the sample 16 and a holographic aluminum lattice is used as the reflecting plate 11.
- the incident angle ⁇ is 10 ° ⁇ ⁇ 15 °. Varyed in range.
- the graph indicated by the solid line in FIG. 9 indicates the change in the phase ⁇ p of the p wave, and the graph indicated by the dashed line indicates the phase ⁇ s of the s wave.
- phase ⁇ p of the p-wave of the reflected light varies abruptly when the incident angle ⁇ ranges from 13 ° to 14 °, and the phase ⁇ s of the s-wave varies smoothly.
- the phase [delta] incident angle phase difference [delta] is zero angle of incidence p and s-wave phase [delta] s intersects ⁇ is the p-wave and s-wave ⁇ of p-wave in FIG. 9, ellipticity tan ⁇ is zero
- the absorption angle ⁇ 0 is as follows.
- the phase difference ⁇ of the reflected light changes from positive to negative or from negative to positive before and after the absorption angle ⁇ 0 .
- the ellipticity tan ⁇ of the reflected light changes from positive to negative or from negative to positive before and after the absorption angle ⁇ 0 . Therefore, by measuring tan ⁇ , the absorption angle ⁇ 0 at which the phase difference ⁇ becomes zero can be measured.
- FIG. 10 is a diagram illustrating a simulation result of the reflectance ⁇ measured by the measurement unit 14.
- a graph indicated by a broken line indicates the reflectance ⁇ p of the p wave
- a graph indicated by a dashed line indicates the reflectance ⁇ s of the s wave.
- the graph shown by the solid line shows the reflectance ⁇ of the reflected light combining the reflectances ⁇ s and ⁇ p of the p wave and the s wave.
- the reflectance of the reflected light ⁇ is the smallest angle of incidence is absorbed angle theta sp.
- a surface plasmon sensor that measures the refractive index n using the reflectance ⁇ of reflected light measures the fluctuation of the reflectance ⁇ of the p wave while varying the incident angle, and detects the minimum point to detect the absorption angle ⁇ . Measure sp .
- the variation of the ellipticity tan ⁇ is measured instead of the variation of the reflectance ⁇ , and the absorption angle ⁇ 0 is measured by detecting the zero point at which the ellipticity tan ⁇ becomes zero. .
- the absorption angle ⁇ 0 of the ellipticity tan ⁇ and the absorption angle ⁇ sp of the reflectance ⁇ are not necessarily the same value, but are very close to each other. Therefore, in the surface plasmon sensor 1 according to the present embodiment, the reflectance ⁇
- the refractive index n of the sample 16 is measured using the absorption angle ⁇ 0 of the ellipticity tan ⁇ instead of the absorption angle ⁇ sp of .
- FIG. 11 shows the incident angle characteristics of the ellipticity tan ⁇ of the reflected light of the sample 16 having the refractive indexes n of “1.0002”, “1.0003”, and “1.0004”, respectively, and the incident angle characteristics of the reflectance ⁇ .
- FIG. 11 and FIG. 12 both show simulation results. 11 and 12, the incident angle characteristics near the absorption angles ⁇ 0 and ⁇ sp are enlarged.
- the solid lines in FIGS. 11 and 12 indicate the incident angle characteristics of the refractive index “1.0002”, the dashed line “1.0003”, and the broken line “1.0004”.
- the incident angle characteristic of each refractive index n is substantially linear. Since the ellipticity tan ⁇ is an incident angle at which the ellipticity tan ⁇ becomes zero, the absorption angle ⁇ 0 of the ellipticity tan ⁇ can be measured by detecting the zero point of each incident angle characteristic. Zero point detection can be easily and accurately measured.
- the incident angle characteristic of each refractive index n is non-linear drawing a downwardly convex gentle curve.
- Absorption angle theta sp reflectance ⁇ since the reflectance ⁇ is the angle of incidence which minimizes the absorption angle theta sp reflectance ⁇ be performed minimal point detection of the incident angle characteristics can be measured.
- the difference between the refractive indexes n is small and the Q value of the incident angle characteristic is small, it seems that the minimum points overlap as shown in FIG. 12, and it is difficult to measure the absorption angle ⁇ sp with high accuracy. .
- the incident angle characteristic of the ellipticity tan ⁇ is substantially linear in the vicinity of the absorption angle ⁇ 0 , even if the difference between the refractive indexes n is small, the difference can be detected as the difference in the absorption angle ⁇ 0 .
- the surface plasmon sensor 1 of the present embodiment the reference material refractive index n s is known and disposed on the reflective plate 11 first as a sample 16, the variation of the ellipticity tan ⁇ of the reflected light in accordance with the procedure shown in FIG. 7 Measure the absorption angle ⁇ 0 .
- a sample 16 whose refractive index n is to be measured is placed on the reflector 11, and the absorption angle ⁇ ′ 0 at which the ellipticity tan ⁇ becomes zero is measured according to the same procedure as that for the reference material.
- the absorption angle ⁇ 0 of the reference material is measured.
- the measurement may be omitted.
- the measuring unit 14 may acquire the incident angle ⁇ from the light source 12 every time the ellipticity tan ⁇ of the reflected light is measured, and acquire the incident angle ⁇ when the ellipticity tan ⁇ becomes zero from the light source 12. May be.
- the measurement unit 14 may obtain the incident angle when the ellipticity tan ⁇ is measured from the range of the incident angle ⁇ and the change in the incident angle ( ⁇ in step S105).
- the measurement unit 14 may control the light source 12 to execute the above-described method of measuring the refractive index n, or a control unit (not shown) may be provided and each unit may be controlled by the control unit.
- the surface plasmon sensor 1 measures the refractive index n of the sample 16 from the fluctuation of the ellipticity tan ⁇ , specifically the absorption angle ⁇ 0 where the ellipticity tan ⁇ becomes zero.
- Entrance angularity of ellipticity tan ⁇ since a substantially linear near the absorption angle theta 0, because the absorption angle theta 0 ellipticity tan ⁇ becomes zero can be measured by performing a zero-point detection, complex, such as a minimum point detection Detection becomes unnecessary, and the absorption angle ⁇ 0 can be measured easily and with high accuracy. For this reason, the refractive index n can be measured even with a substance having a small difference in the refractive index n such as gas.
- FIG. 13 is a diagram showing an outline of the surface plasmon sensor 2.
- the metal layer 20 of the reflector 21 has the one-dimensional thin film periodic structure shown in FIG. 2C and the incident light is incident from the substrate 25 side. Different from the surface plasmon sensor 1 of FIG.
- the reflection plate 21 includes a substrate 25 that transmits light, such as a silicon substrate, and a metal layer 20 having a one-dimensional thin film periodic structure.
- the reflector 21 is laminated in the order of the substrate 25 and the metal layer 20 from the side closer to the light source 12, and the sample 16 is disposed on the surface of the metal layer 20 facing the substrate 25.
- the metal layer 20 of this embodiment has a periodic structure on both surfaces, you may make it have a periodic structure only in the surface where the sample 16 is arrange
- the refractive index n of the sample 16 is the same as in the first embodiment. Can be measured.
- FIG. 14 is a diagram showing an outline of the surface plasmon sensor 3.
- the surface plasmon sensor 3 according to the present embodiment is the same as the surface plasmon sensor 1 of FIG. 1 in that the incident angle ⁇ and the wavelength ⁇ are constant and the variation of the ellipticity tan ⁇ is measured while varying the azimuth angle ⁇ of the reflector 31. Different.
- the reflection plate 31 has a driving device (not shown) and rotates so that the azimuth angle ⁇ varies.
- the measuring unit 34 measures the variation in ellipticity of the reflected light received by the light receiving unit 13.
- the measuring unit 34 measures an azimuth angle ⁇ 0 at which the measured ellipticity is zero (hereinafter referred to as an absorption azimuth angle ⁇ 0 ).
- Steps up to step S104 are the same as those in FIG.
- the reflector 31 changes the azimuth angle ⁇ to ⁇ + ⁇ (S305). If the ellipticity tan ⁇ has not been measured at all azimuth angles ⁇ for measuring the variation of the ellipticity (no in S306), the process returns to step S102. On the other hand, when the ellipticity tan ⁇ is measured at all azimuth angles ⁇ (Yes in S306), the measurement of the sample 16 is finished.
- the refractive indexes n are “1.0003” and “1.00039”, respectively.
- the solid line represents the azimuth angle characteristic with the refractive index “1.0001”, the broken line “1.0003”, and the alternate long and short dash line “1.00039”.
- the azimuth characteristics of each refractive index n are substantially linear. Therefore, the absorption azimuth angle ⁇ 0 at which the ellipticity tan ⁇ becomes zero can be easily and accurately measured even if the azimuth angle characteristic is used as in the incident angle characteristic of the first embodiment.
- the reference material refractive index n s is known and disposed on the reflective plate 31, the ellipticity tan ⁇ when changing the azimuth angle according to the procedure shown in FIG. 15 The fluctuation is measured, and the absorption azimuth angle ⁇ 0 at which the ellipticity tan ⁇ becomes zero is measured.
- the sample 16 whose refractive index n is to be measured is placed on the reflector 31 and the absorption azimuth angle ⁇ ′ 0 at which the ellipticity tan ⁇ becomes zero is measured according to the same procedure as that for the reference material.
- the absorption azimuth angle ⁇ 0 of the reference material is measured.
- the refractive index n s and the absorption azimuth angle ⁇ 0 of the reference material are known, the measurement may be omitted.
- the measuring unit 34 may acquire the azimuth angle ⁇ of the reflecting plate 31 from the reflecting plate 31 every time the ellipticity tan ⁇ of the reflected light is measured, and reflects the azimuth angle ⁇ when the ellipticity tan ⁇ becomes zero. You may make it acquire from the board 31.
- the measurement unit 34 may obtain the azimuth angle ⁇ when the ellipticity tan ⁇ is measured from the range of the azimuth angle ⁇ and the change in the azimuth angle ⁇ ( ⁇ in step S305).
- the measurement unit 34 may control the reflecting plate 31 to execute the above-described method of measuring the refractive index n, or a control unit (not shown) may be provided and each unit may be controlled by the control unit. Good.
- the ellipticity varies when the azimuth angle ⁇ is varied even if the incident angle ⁇ is constant, so that the refraction of the sample 16 does not occur without varying the incident angle ⁇ .
- the rate n can be measured easily and with high accuracy.
- FIG. 17 is a diagram showing an outline of the surface plasmon sensor 4.
- the surface plasmon sensor 4 according to this embodiment is different from the surface plasmon sensor 1 of FIG. 1 in that the incident angle ⁇ and the azimuth angle ⁇ are constant and the variation of the ellipticity tan ⁇ is measured while varying the wavelength ⁇ of the incident light. .
- the light source 42 is composed of, for example, a semiconductor laser.
- the semiconductor laser can change the wavelength of incident light by receiving a control signal from a control unit (not shown).
- the light source 42 may include the control unit.
- the light source 42 irradiates incident light while changing the wavelength ⁇ of the incident light.
- the measuring unit 44 measures the variation in ellipticity of the reflected light received by the light receiving unit 13.
- the measuring unit 44 measures a wavelength ⁇ 0 (hereinafter referred to as an absorption wavelength ⁇ 0 ) at which the measured ellipticity is zero.
- ⁇ n the refractive index difference between the sample 16 and the reference material. Since the other structure is the same as that of the surface plasmon sensor 1 shown in FIG. 1, description is abbreviate
- Steps up to step S104 are the same as those in FIG.
- the light source 42 changes the irradiating wavelength ⁇ to ⁇ + ⁇ (S405). If the ellipticity tan ⁇ has not been measured at all wavelengths for measuring the variation in ellipticity (no in S406), the process returns to step S102. On the other hand, when the ellipticity tan ⁇ is measured at all wavelengths (Yes in S406), the measurement of the sample 16 is finished.
- FIG. 19 shows the wavelength characteristics of the ellipticity tan ⁇ of the reflected light in the sample 16 whose refractive index n is “1.0003”, “1.00039”, and “1.0001”, respectively.
- the broken line indicates the wavelength characteristic of the refractive index “1.0001”, the solid line indicates “1.0003”, and the dashed line indicates “1.00039”.
- the wavelength characteristic of each refractive index n is substantially linear. Therefore, the absorption wavelength ⁇ 0 at which the ellipticity tan ⁇ becomes zero can be easily and accurately measured even when the wavelength characteristic is used in the same manner as the incident angle characteristic of the first embodiment.
- the reference material refractive index n s is known and disposed on the reflective plate 11, variations in the ellipticity tan ⁇ when changing the wavelength in accordance with the procedure shown in FIG. 18 And the absorption wavelength ⁇ 0 at which the ellipticity tan ⁇ becomes zero is measured.
- a sample 16 whose refractive index n is to be measured is placed on the reflector 11, and the absorption wavelength ⁇ ′ 0 at which the ellipticity tan ⁇ becomes zero is measured according to the same procedure as that for the reference material.
- the absorption wavelength ⁇ 0 of the reference material is measured.
- the measurement may be omitted if the refractive index n s and the absorption wavelength ⁇ 0 of the reference material are known.
- the measuring unit 44 may acquire the wavelength ⁇ of the incident light from the light source 42 every time the ellipticity tan ⁇ of the reflected light is measured, and acquire the wavelength ⁇ when the ellipticity tan ⁇ becomes zero from the light source 42. You may do it.
- the measurement unit 44 may obtain the wavelength ⁇ when the ellipticity tan ⁇ is measured from the range of the wavelength ⁇ and the change in the wavelength ⁇ ( ⁇ in step S405).
- the measurement unit 44 may control the light source 42 to execute the above-described method of measuring the refractive index n.
- a control unit (not shown) may be provided and each unit may be controlled by the control unit. .
- the ellipticity varies when the wavelength ⁇ is varied even when the incident angle ⁇ is constant. Therefore, the refractive index of the sample 16 is not varied without varying the incident angle ⁇ . n can be measured easily and with high accuracy. Since it is not necessary to change the incident angle ⁇ , the light source 42 does not require a driving device, and the surface plasmon sensor 4 can be downsized.
- the surface plasmon sensor 5 according to the fifth embodiment will be described with reference to FIG.
- the surface plasmon sensor 5 according to the present embodiment includes a control unit 57 that controls the wavelength ⁇ of incident light emitted from the light source 52 based on the ellipticity tan ⁇ measured by the measurement unit 54.
- the light source 52 controls a semiconductor laser (not shown) based on a control signal input from the control unit 57 and irradiates incident light having a wavelength ⁇ .
- the measuring unit 54 measures the ellipticity tan ⁇ from the reflected light received by the light receiving unit 13.
- the measuring unit 54 outputs the ellipticity tan ⁇ to the control unit 57.
- the control unit 57 generates a control signal based on the ellipticity tan ⁇ input from the measurement unit 54 so that the light source 52 emits incident light having a wavelength ⁇ at which the ellipticity tan ⁇ becomes zero.
- the control unit 57 outputs a control signal to the light source 52.
- the information input from the measurement unit 54 to the control unit 57 may be information that allows the control unit 57 to identify whether or not the ellipticity tan ⁇ is zero, even if it is not the ellipticity tan ⁇ itself. For example, information such as the phase difference ⁇ between the p wave and the s wave and which phase is advanced may be input from the measurement unit 54 to the control unit 57.
- Steps up to step S104 are the same as those in FIG.
- the measuring unit 54 measures the ellipticity tan ⁇ (step S104), and outputs the measured ellipticity tan ⁇ to the control unit 57. If the ellipticity tan ⁇ is not zero (no in step S506), the control unit 57 changes the wavelength ⁇ and generates a control signal so as to be ⁇ + ⁇ (step S507). When the control unit 57 passes the control signal to the light source 52, the control unit 57 returns to Step S102. On the other hand, if the ellipticity is zero (yes in step S506), the ellipticity variation measurement is terminated.
- the ellipticity tan ⁇ when the wavelength characteristic of the ellipticity tan ⁇ near the absorption wavelength ⁇ 0 is substantially linear with a positive slope, when the wavelength ⁇ is changed in step S507, the ellipticity tan ⁇ is The wavelength ⁇ may be shortened when positive, and may be increased when negative. Note that the wavelength characteristic of the ellipticity tan ⁇ may be substantially linear with a negative slope near the absorption wavelength ⁇ 0 . In this case, the wavelength ⁇ may be shortened when the ellipticity tan ⁇ is negative, and may be changed so as to be longer when the ellipticity tan ⁇ is positive.
- the reference material refractive index n s is known and disposed on the reflective plate 11, variations in the ellipticity tan ⁇ when changing the wavelength in accordance with the procedure shown in FIG. 21 And the absorption wavelength ⁇ 0 at which the ellipticity tan ⁇ becomes zero is measured.
- a sample 16 whose refractive index n is to be measured is placed on the reflector 11, and the absorption wavelength ⁇ ′ 0 at which the ellipticity tan ⁇ becomes zero is measured according to the same procedure as that for the reference material.
- the refractive index n of the sample 16 is measured from the absorption wavelengths ⁇ 0 and ⁇ ′ 0 as in the fourth embodiment.
- the measurement of the refractive index n may be performed by the measurement unit 54 as in the fourth embodiment, or may be performed by the control unit 57.
- the control unit 57 may be configured to have the function of the measurement unit 54, and the measurement unit 54 may be omitted.
- the measurement unit 54 feeds back the ellipticity tan ⁇ so that the wavelength ⁇ of the light source 52 can be changed according to the measured ellipticity tan ⁇ . Become. Thereby, the absorption wavelength ⁇ 0 can be measured in a short time, and the refractive index measurement time of the sample 16 can be shortened.
- the wavelength ⁇ of the light source 52 is changed according to the measured ellipticity tan ⁇ , but the incident angle ⁇ may be changed instead of the wavelength ⁇ to measure the absorption angle ⁇ 0 , The angle ⁇ may be changed and the absorption azimuth angle ⁇ 0 may be measured.
- the control unit 57 controls the reflector 11 instead of the light source 52.
- the surface plasmon sensor 6 according to the sixth embodiment will be described with reference to FIG.
- the surface plasmon sensor 6 according to the present embodiment is different from the surface plasmon sensor 5 according to the fourth embodiment in the method of measuring the refractive index n in the measurement unit 64. Since the other configuration is the same, the description thereof is omitted.
- the absorption wavelength ⁇ 0 of the reference material is measured. Since this is measured in the same manner as in the fifth embodiment, description thereof is omitted.
- the sample 16 whose refractive index n is to be measured is placed on the reflecting plate 11, and incident light whose wavelength ⁇ is the absorption wavelength ⁇ 0 of the reference material is irradiated from the light source 52.
- the measuring unit 64 measures the ellipticity tan ⁇ of the reflected light received by the light receiving unit 13.
- the refractive index of the sample 16 placed on the reflection plate 11 changes from n s to n s + [Delta] n
- the incident angle characteristic of the ellipticity tan ⁇ also theta + to ⁇ changes.
- the change ⁇ in the absorption angle theta 0 ellipticity tan ⁇ becomes zero, but may be measured change ⁇ n in refractive index n s, constant wavelength lambda 0 and the incident by measuring the change in ellipticity tan ⁇ at the corners theta 0 (arrow in FIG. 23)
- the change ⁇ n in refractive index n s may be measured.
- the ellipticity Tankai of Sample 16 Tankai a linear portion of the incident angle characteristics of ellipticity Tankai - intended to be from Tankai + range.
- the measurement unit 64 measures the wavelength ⁇ 0 at which the ellipticity tan ⁇ of the reference material becomes zero at a constant incident angle ⁇ , and the ellipticity tan ⁇ of the sample 16 at the incident angle ⁇ and wavelength ⁇ 0. Measure.
- the measuring unit 64 measures the change ⁇ n in the refractive index n of the sample 16 from the measured ellipticity tan ⁇ of the sample 16.
- the wavelength ⁇ 0 where the ellipticity tan ⁇ of the reference material is zero is measured by changing the wavelength ⁇ with the incident angle constant, but the reference angle can be changed by changing the incident angle ⁇ while keeping the wavelength constant.
- the ellipticity tan ⁇ of the sample 16 may be measured at an incident angle ⁇ 0 and a wavelength ⁇ at which the ellipticity tan ⁇ of the substance becomes zero. Further, even when the wavelength ⁇ and the incident angle ⁇ are constant and the azimuth angle ⁇ is changed, the ellipticity tan ⁇ of the sample 16 is measured at the incident angle ⁇ and azimuth angle ⁇ 0 where the ellipticity tan ⁇ of the reference material becomes zero. Good.
- the refractive index n of the sample 16 is measured by using the change in the linear part of the incident angle characteristic of the ellipticity tan ⁇ accompanying the refractive index change of the sample 16.
- the ellipticity of the sample 16 can be measured only once. Thereby, measurement time can be shortened significantly.
- the refractive index n can be measured with higher accuracy even if the difference in the refractive index n is small, such as gas.
- the surface plasmon sensor 7 according to the seventh embodiment will be described with reference to FIG.
- the surface plasmon sensor 7 according to the present embodiment is different from the surface plasmon sensor 1 in that the measurement sensitivity of the refractive index n is improved by adjusting the reflecting plate 71. Since the other configuration is the same, description thereof is omitted.
- FIG. 25 shows the incident angle characteristics of the ellipticity tan ⁇ when the azimuth angle ⁇ of the reflecting plate 71 and the shape of the grating grooves (here, the groove depth H) are changed.
- FIG. 25 is a diagram illustrating a simulation result when air is used as the sample 16. The method for measuring the variation of the ellipticity tan ⁇ is the same as in FIG.
- the inclination of the ellipticity tan ⁇ near the absorption angle ⁇ 0 is changed by changing the azimuth angle ⁇ of the reflecting plate 71 and the groove shape (here, the groove depth H).
- the absorption angle ⁇ 0 can be obtained with higher accuracy when the inclination of the ellipticity tan ⁇ is larger. Therefore, in the surface plasmon sensor 7 according to the present embodiment, the inclination of the ellipticity tan ⁇ around the absorption angle ⁇ 0 is adjusted by adjusting the azimuth angle ⁇ of the reflecting plate 71 and the groove shape (for example, the groove depth H). The variation of the ellipticity tan ⁇ is measured so as to be the largest.
- the adjustment method of the reflecting plate 71 while changing the shape of the azimuthal angle ⁇ and the groove of the reflector 71 to measure the incident angle characteristics of the ellipticity Tankai, the inclination of the ellipticity Tankai near the absorption angle theta 0 is largest
- the azimuth angle ⁇ of the reflector 71 and the groove shape may be determined.
- the ellipticity tan ⁇ approaches ⁇ 1
- the inclination of the ellipticity tan ⁇ before and after the absorption angle ⁇ 0 increases. Therefore, while changing the groove shape and the azimuth angle ⁇ , the phase difference ⁇ and the reflectance of the p wave and the s wave of the reflected light are measured, and the inclination of the ellipticity tan ⁇ around the absorption angle ⁇ 0 is the largest.
- the azimuth angle ⁇ of 71 and the shape of the groove may be determined. It is sufficient to adjust the reflection plate 71 once before measuring the refractive index n.
- the surface plasmon sensor 7 can increase the inclination of the ellipticity tan ⁇ near the absorption angle ⁇ 0 by adjusting the reflecting plate 71 before measuring the refractive index n. .
- the absorption angle ⁇ 0 can be measured with high accuracy, and the measurement sensitivity of the refractive index n can be improved.
- the reflection plate of the surface plasmon sensor 1 is adjusted, but the measurement sensitivity of the refractive index n can be improved by adjusting the reflection plates of the surface plasmon sensors 2 and 4 to 6 in the same manner. Good. Further, the inclination of the ellipticity tan ⁇ near the absorption angle theta 0 and adjust the shape of the groove of the reflector of the surface plasmon sensor 3 is increased, it may be to improve the measurement sensitivity of the absorption angle theta 0.
- FIG. 26 is a diagram showing an outline of the surface plasmon sensor 8.
- the surface plasmon sensor 8 according to the present embodiment is different from the surface plasmon sensor according to each of the embodiments described above in that the refractive index is measured based on the phase information that is the basis of the above-described ellipticity tan ⁇ calculation.
- the p-wave phase ⁇ p and the s-wave phase ⁇ s of the reflected light change from positive to negative or from negative to positive before and after the absorption angle ⁇ 0.
- the phase difference ⁇ of the reflected light also changes from positive to negative or from negative to positive before and after the absorption angle ⁇ 0 .
- the phase difference ⁇ by measuring the ellipticity tan ⁇ had to identify the angle of incidence is zero absorption angle theta 0.
- the eighth embodiment by using a polarizing plate, a value corresponding to the phase difference ⁇ between the p wave and the s wave of the reflected light is measured, and the incident angle (absorption angle ⁇ ) at which the phase difference ⁇ becomes zero. 0 ) can be measured.
- the absorption angle ⁇ 0 can be specified without measuring the ellipticity tan ⁇ , and thus the refractive index n can be specified. That is, a device such as a polarimeter for measuring the ellipticity tan ⁇ becomes unnecessary.
- the surface plasmon sensor 8 includes a splitter 87, polarizing plates 88a and 88b, and two light receiving portions 83a and 83b.
- the other configuration is the same as that of the surface plasmon sensor 1 shown in FIG.
- the splitter 87 is disposed on the path of the reflected light reflected by the reflecting plate 11, divides the light beam of the reflected light into two, makes one light beam enter the light receiving unit 83a, and makes the other light beam receive the light receiving unit 83b. To enter.
- the polarizing plate 88a is disposed on the path of one light beam divided by the splitter 87, and selectively passes a component polarized in a specific direction in the light beam.
- the polarizing plate 88b is disposed on the path of the other light beam divided by the splitter 87, and selectively passes a component polarized in a specific direction in the light beam.
- the light receiving units 83a and 83b receive the reflected light polarized in a specific direction, respectively.
- the direction of the transmission axis of the polarizing plate 88a and the polarizing plate 88b is adjusted so as to pass components polarized in different directions.
- the polarizing plate 88a is adjusted so as to selectively pass light polarized in the same direction as the inclination angle ⁇ of the ellipse of the reflected light
- the polarizing plate 88b is Adjustment is made so that light polarized in the direction orthogonal to the inclination angle ⁇ of the ellipse of the reflected light is selectively transmitted. In this way, the increase and decrease of the phase difference ⁇ of the reflected light can be measured by allowing each polarizing plate to selectively pass light having an elliptical inclination angle of 90 °.
- At least one of the polarizing plates 88a and 88b is adjusted so that a part of the light polarized in the direction orthogonal to the direction of the inclination angle ⁇ of the ellipse of the reflected light can pass.
- at least one of the light receiving units measures the increasing / decreasing tendency of the phase difference ⁇ of the reflected light, and the measuring unit 84 can measure the absorption angle ⁇ 0 at which the phase difference ⁇ becomes zero.
- the measuring unit 84 measures the intensity fluctuation of the reflected light received by the light receiving units 83a and 83b via the polarizing plates 88a and 88b. And the measurement part 84 can measure absorption angle (theta) 0 based on the intensity
- FIG. 27 is a diagram showing the relationship between the incident angle ⁇ and the inclination angle ⁇ of the ellipse. This figure shows the result of simulating the variation of the inclination angle ⁇ of the ellipse at each incident angle ⁇ .
- a holographic aluminum lattice is used as the reflecting plate 11.
- the wavelength ⁇ 670 nm
- the incident angle ⁇ is in the range of 3 ° ⁇ ⁇ 15 °. It was changed with.
- the inclination angle ⁇ of the ellipse has a peak centered on the absorption angle ⁇ 0 .
- the incident angle theta 1, theta 2 is offset from the absorption angle theta 0, but within a few ° from the absorption angle theta 0.
- FIG. 28 is a diagram showing a simulation result showing the received light intensity measured by the measurement unit 84 with the inclination angle ⁇ of the ellipse of incident light being 30 °.
- a holographic aluminum lattice is used as the reflecting plate 11.
- the wavelength ⁇ 670 nm
- the incident angle ⁇ is in the range of 3 ° ⁇ ⁇ 15 °. It was changed with.
- the light receiving intensity Ea of the light receiving portion 83a is indicated by a one-dot chain line
- the light receiving intensity Eb of the light receiving portion 83b is indicated by a two-dot chain line
- a difference Ea-Eb of the light receiving intensity is indicated by a dotted line.
- the received light intensities Ea and Eb and the difference Ea ⁇ Eb change linearly within a predetermined range with the incident angle ⁇ 1 as the center. Therefore, by measuring or simulating a linear change in this predetermined range with a reference sample, and using the measurement result or simulation result as calibration data, the fluctuation of the incident angle ⁇ 1 accompanying the fluctuation of the refractive index n is measured. can do.
- FIG. 29 is a flowchart showing a procedure for measuring the refractive index n according to this embodiment.
- the fluctuation of the intensity of reflected light from the sample 16 (hereinafter referred to as reflected light intensity I) when the sample 16 is arranged on the reflector 11 is measured.
- the sample 16 is placed on the reflecting plate 11 (S201), and incident light having an incident angle ⁇ and a wavelength ⁇ is irradiated from the light source 12 (S202).
- the light source 12 emits p-wave incident light.
- the incident angle ⁇ of the incident light is an angle within a predetermined range with the above-described incident angle ⁇ 1 as a center.
- the light receivers 83a and 83b receive the reflected light of the incident light reflected by the reflecting plate 11 through the sample 16 (S203).
- FIG. 30 is a diagram illustrating a simulation result indicating the received light intensity measured by the measurement unit 84 with the inclination angle ⁇ of the ellipse of incident light set to 70 °.
- a holographic aluminum lattice is used as the reflecting plate 11.
- the incident angle ⁇ is in the range of 3 ° ⁇ ⁇ 15 °. It was changed with.
- the received light intensity Ea of the light receiving unit 83a is indicated by a one-dot chain line
- the received light intensity Eb of the light receiving unit 83b is indicated by a two-dot chain line
- the difference Ea-Eb of the received light intensity is indicated by a dotted line.
- the received light intensities Ea and Eb and the difference Ea ⁇ Eb change linearly within a predetermined range with the incident angle ⁇ 2 as the center, so that the incident angle can be obtained by using calibration data in the predetermined range. Variations in ⁇ 2 can be measured.
- the surface plasmon sensor 8 can measure the refractive index n using a value corresponding to the phase difference ⁇ obtained using the polarizing plate. That is, since it is not necessary to measure the ellipticity tan ⁇ , the refractive index n can be measured without using an expensive and complicated device for measuring the ellipticity tan ⁇ such as a polarimeter.
- FIG. 31 is a diagram showing an outline of the surface plasmon sensor 9.
- the surface plasmon sensor 9 according to the present embodiment is different from the surface plasmon sensor 8 according to the eighth embodiment described above in that it does not include a splitter but includes one polarizing plate and one light receiving unit.
- the surface plasmon sensor 9 includes a polarizing plate 98 and a light receiving portion 93.
- the polarizing plate 98 is disposed on the path of the reflected light, and selectively transmits a component polarized in a specific direction in the reflected light. Thus, the polarizing plate 98 receives the reflected light polarized in a specific direction.
- the measuring unit 94 can measure the intensity fluctuation of the reflected light received by the light receiving unit 93 via the polarizing plate 98. And the measurement part 94 can measure an incident angle (absorption angle (theta) 0 ) based on the intensity
- Other configurations are the same as those of the surface plasmon sensor 8 shown in FIG.
- the method for measuring the refractive index n is the same as the method for measuring the refractive index based on the received light intensities Ea and Eb in the eighth embodiment, and the description thereof will be omitted.
- the surface plasmon sensor 9 can measure the refractive index n by obtaining a value corresponding to the phase difference ⁇ using a pair of polarizing plates and a light receiving unit.
- the reflectors of the surface plasmon sensors 3 to 9 according to the third to ninth embodiments may be configured so that incident light is incident from the substrate 25 side as in the second embodiment.
- the refractive index n can also be measured using ⁇ 0 , the absorption azimuth angle ⁇ 0 , and the absorption wavelength ⁇ 0 .
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Abstract
Description
上述したように吸収角θspは、反射率ρが急激に減少する角度であるため、吸収角θspを測定するには最小点検出を行わなければならず、測定が複雑であるという問題があった。
本発明の第1実施形態に係る表面プラズモンセンサ1を説明する。図1は、本実施形態に係る表面プラズモンセンサ1の概略を示す図である。
図1の表面プラズモンセンサ1は、周期構造を有する金属層10を備える反射板11と、反射板11上に入射光を照射する光源12と、反射板で反射した反射光を受光する受光部13と、反射光の楕円率の変動から反射板11上に配置された試料の屈折率nを測定する計測部14と、を備える。
反射板11は、例えばシリコン等の基板15と、基板15上に積層された例えばアルミニウム等の金属層10と、を有する。
反射板11の上には屈折率nの測定対象となる試料16や、試料16の屈折率n測定の基準となる基準物質等が配置される。
図4を用いて、受光部13が受光する反射光について説明する。図4(a)に示すように、反射光には入射面S1に対して平行なp波成分と、垂直なs波成分とに分けられる。光を進行方向から見るとp波とs波との位相差δに応じて、光の電界ベクトルは、図4(b)のように楕円状に旋回しているように見える。このとき長軸の長さをa、短軸の長さをbとすると楕円率tanχは、tanχ=b/aで求められる。また、光の電界ベクトルが成す楕円の長軸がx方向に対して成す角を楕円の傾き角ψと呼ぶことにする。
受光部13は、入射光が試料16を介して反射板11で反射した光(反射光)を受光する(S103)。
光源12は照射する入射光の入射角θを変更し、θ+Δθとする(S105)。
のシミュレーション結果を示す。ここでは、試料16として空気を用い、反射板11としてホログラフィックアルミ格子を用いている。格子の溝の深さをH=72nm、格子の周期dを、d=556nm、方位角φをφ=30°、波長λをλ=670nmとし、入射角
θを10°<θ<15°の範囲で変化させた。
ρsを示している。実線で示すグラフは、p波及びs波の反射率ρs、ρpを合わせた反射光の反射率ρを示している。
「1.0003」、破線が「1.0004」の入射角特性を示している。
次に、反射板11に屈折率nを測定したい試料16を配置し、基準物質と同様の手順に従って楕円率tanχがゼロとなる吸収角θ’0を測定する。
測定した吸収角の差Δθ0(=θ’0-θ0)から基準物質の屈折率nsと、試料16の屈折率nの差Δn(=n-ns)を測定する。
本発明の第2実施形態に係る表面プラズモンセンサ2を説明する。図13は表面プラズモンセンサ2の概略を示す図である。本実施形態に係る表面プラズモンセンサ2は反射板21の金属層20が図2(c)に示す一次元薄膜周期構造を有している点及び基板25側から入射光を入射している点で図1の表面プラズモンセンサ1と異なる。
本発明の第3実施形態に係る表面プラズモンセンサ3を説明する。図14は、表面プラズモンセンサ3の概略を示す図である。本実施形態に係る表面プラズモンセンサ3は、入射角θ及び波長λを一定とし、反射板31の方位角φを変動させながら楕円率tanχの変動を測定する点で図1の表面プラズモンセンサ1と異なる。
計測部34は、受光部13が受光した反射光の楕円率の変動を測定する。計測部34は、測定した楕円率がゼロとなる方位角φ0(以下、吸収方位角φ0と称する。)を測定する。計測部34は、反射板11上に基準物質が配置された場合の吸収方位角φ0と、試料16が配置された場合の吸収方位角φ’0との差Δφ0(=φ’0-φ0)から試料16と基準物質との屈折率の差Δnを測定する。
そのほかの構成は図1に示す表面プラズモンセンサ1と同様であるため説明を省略する。
、「1.0001」である試料16における反射光の楕円率tanχの方位角特性を示す。実線が屈折率「1.0001」、破線が「1.0003」、一点鎖線が「1.00039」の方位角特性を示している。なお、図16では、入射角θをθ=11.3°とし、波長
λをλ=670nmとした場合の空気の楕円率tanχの変動を計測したシミュレーション結果を示している。
次に、反射板31に屈折率nを測定したい試料16を配置し、基準物質と同様の手順に従って楕円率tanχがゼロとなる吸収方位角φ’0を測定する。
測定した吸収方位角の差Δφ0(=φ’0-φ0)から基準物質の屈折率nsと、試料16の屈折率nの差Δn(=n-ns)を測定する。
本発明の第4実施形態に係る表面プラズモンセンサ4を説明する。図17は、表面プラズモンセンサ4の概略を示す図である。本実施形態に係る表面プラズモンセンサ4は、入射角θ及び方位角φを一定とし、入射光の波長λを変動させながら楕円率tanχの変動を測定する点で図1の表面プラズモンセンサ1と異なる。
そのほかの構成は図1に示す表面プラズモンセンサ1と同様であるため説明を省略する。
次に、反射板11に屈折率nを測定したい試料16を配置し、基準物質と同様の手順に従って楕円率tanχがゼロとなる吸収波長λ’0を測定する。
測定した吸収波長の差Δλ0(=λ’0-λ0)から基準物質の屈折率nsと、試料16の屈折率nの差Δn(=n-ns)を測定する。
図20を用いて第5実施形態に係る表面プラズモンセンサ5を説明する。本実施形態に係る表面プラズモンセンサ5は、計測部54が計測する楕円率tanχに基づいて光源52が照射する入射光の波長λを制御する制御部57を備える。
制御部57は、楕円率tanχがゼロでない場合(ステップS506のno)、波長λを変更しλ+Δλとなるよう制御信号を生成する(ステップS507)。制御部57は、制御信号を光源52に渡すとステップS102に戻る。一方、楕円率がゼロの場合(ステップS506のyes)、楕円率変動測定を終了する。
次に、反射板11に屈折率nを測定したい試料16を配置し、基準物質と同様の手順に従って楕円率tanχがゼロとなる吸収波長λ’0を測定する。吸収波長λ0、λ’0から第4実施形態と同様に試料16の屈折率nを測定する。
図22を用いて第6実施形態に係る表面プラズモンセンサ6を説明する。
本実施形態に係る表面プラズモンセンサ6は、計測部64での屈折率nの測定方法が第4実施形態に係る表面プラズモンセンサ5と異なる。それ以外の構成は同じであるため説明は省略する。
図24を用いて第7実施形態に係る表面プラズモンセンサ7を説明する。
本実施形態に係る表面プラズモンセンサ7は、反射板71を調整することで屈折率nの測定感度を向上させている点で表面プラズモンセンサ1と異なる。それ以外の構成は同じであるため説明を省略する。
本発明の第8実施形態に係る表面プラズモンセンサ8を説明する。図26は、表面プラズモンセンサ8の概略を示す図である。本実施形態に係る表面プラズモンセンサ8は、上述した楕円率tanχ算出の元となる位相情報に基づいて屈折率を測定する点で上述した各実施形態に係る表面プラズモンセンサと異なる。
スプリッタ87は、反射板11が反射する反射光の経路上に配置されており、反射光の光束を2つに分割し、一方の光束を受光部83aへ入射させ、他方の光束を受光部83bへ入射させる。
図27は、入射角θと楕円の傾き角ψの関係を示す図である。同図には、各入射角θにおける楕円の傾き角ψの変動をシミュレーションした結果を示してある。ここでは、反射板11としてホログラフィックアルミ格子を用いている。格子の溝の深さをH=72nm、格子の周期dをd=556nm、方位角φをφ=30°、波長λをλ=670nmとし、入射角θを3°<θ<15°の範囲で変化させた。同図に示すように、楕円の傾き角ψは吸収角θ0を中心とするピークを有している。
受光部83a,83bは、入射光が試料16を介して反射板11にて反射された反射光を受光する(S203)。
このようにして測定された反射光強度Iに基づいて、計測部84は、上述した校正データを参照しつつ反射光強度Iの校正データからの変動量ΔIを特定する。そして、計測部84は、変動量ΔIに基づいて基準物質の屈折率nsと試料16の屈折率の差Δn(=n-ns)を測定する。
本発明の第9実施形態に係る表面プラズモンセンサ9を説明する。図31は、表面プラズモンセンサ9の概略を示す図である。本実施形態に係る表面プラズモンセンサ9は、スプリッタを備えず、偏光板と受光部を1つずつ備える点で、上述した第8実施形態に係る表面プラズモンセンサ8と異なる。
Claims (14)
- 周期構造を有する金属層を備え、試料が配置された反射板と、
前記反射板に入射光を照射する光源と、
前記反射板で反射した反射光を受光する受光部と、
前記試料を透過して反射した反射光に含まれる偏光方向の異なる2種類の波の位相差情報に基づいて前記試料の屈折率を測定する計測部と、を備えることを特徴とする表面プラズモンセンサ。 - 前記反射光に含まれる偏光方向の異なる2種類の波は、前記反射光に含まれるs波とp波であることを特徴とする請求項1に記載の表面プラズモンセンサ。
- 前記位相差情報は、前記反射光の楕円率の変動であることを特徴とする請求項1又は請求項2に記載の表面プラズモンセンサ。
- 前記光源は、前記反射板に照射する入射角を変化させながら前記入射光を照射し、
前記計測部は、前記2種類の波の位相差がゼロになる前記入射角に基づいて前記試料の屈折率を測定することを特徴とする請求項1乃至請求項3のいずれか1項に記載の表面プラズモンセンサ。 - 前記反射板は、前記入射光の入射面が前記周期構造の周期方向に対する方位角を変化させながら前記入射光を反射し、
前記計測部は、前記2種類の波の位相差がゼロになる前記方位角に基づいて前記試料の屈折率を測定することを特徴とする請求項1乃至請求項3のいずれか1項に記載の表面プラズモンセンサ。 - 前記光源は、前記入射光の波長を変化させながら前記入射光を照射し、
前記計測部は、前記2種類の波の位相差がゼロになる前記波長に基づいて前記試料の屈折率を測定することを特徴とする請求項1乃至請求項3のいずれか1項に記載の表面プラズモンセンサ。 - 前記計測部が測定した前記2種類の波の位相差がゼロになるように前記周期構造の周期方向に対する方位角を変更するように前記反射板を制御する制御部をさらに備えることを特徴とする請求項1乃至請求項3のいずれか1項又は請求項5に記載の表面プラズモンセンサ。
- 前記計測部が測定した前記2種類の波の位相差がゼロになるように前記入射角を変更するよう前記光源を制御する制御部をさらに備えることを特徴とする請求項1乃至請求項4のいずれか1項に記載の表面プラズモンセンサ。
- 前記計測部が測定した前記2種類の波の位相差がゼロになるように前記波長を変更するよう前記光源を制御する制御部をさらに備えることを特徴とする請求項1乃至請求項3のいずれか1項又は請求項6に記載の表面プラズモンセンサ。
- 前記光源は、屈折率測定の基準となる基準物質を反射板に配置したときの反射光に含まれる前記2種類の波の位相差がゼロとなる入射角及び波長を有する前記入射光を前記試料に照射し、
前記計測部は、前記反射光から得た位相情報に基づき前記試料の屈折率を測定することを特徴とする請求項1乃至請求項9のいずれか1項に記載の表面プラズモンセンサ。 - 前記2種類の波の位相差がゼロとなる前後の前記楕円率の変動量が大きくなるように前記反射板の方位角及び格子の溝の深さを調整することを特徴とする請求項1乃至請求項10のいずれか1項に記載の表面プラズモンセンサ。
- 入射面に対して前記反射光の平行な成分及び垂直な成分の位相差を略直角、前記反射光の反射率が前記平行な成分と前記垂直な成分とで略等しくなるように、前記反射板の方位角及び溝の形状を調整することを特徴とする請求項1乃至請求項11のいずれか1項に記載の表面プラズモンセンサ。
- 前記光源は、前記反射板の前記金属層が設けられた面と対向する面から入射されるように前記入射光を照射し、
前記金属層は薄膜周期構造を有することを特徴とする請求項1乃至請求項12のいずれか1項に記載の表面プラズモンセンサ。 - 周期構造を有する金属層を備える反射板に配置された試料の屈折率を測定する表面プラズモンセンサを用いた屈折率の測定方法であって、
光源から前記反射板に入射光を照射するステップと、
前記試料を透過して前記反射板で反射した反射光を受光部で受光するステップと、
前記受光部で受光した反射光に含まれる偏光方向の異なる2種類の波の位相差情報に基づいて前記試料の屈折率を測定するステップと、を備えることを特徴とする屈折率の測定方法。
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Publication number | Priority date | Publication date | Assignee | Title |
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US3594064A (en) * | 1969-06-25 | 1971-07-20 | Du Pont | Enhanced magneto-optic mirror apparatus |
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JP5397577B2 (ja) | 2007-03-05 | 2014-01-22 | オムロン株式会社 | 表面プラズモン共鳴センサ及び当該センサ用チップ |
GB0721482D0 (en) * | 2007-11-01 | 2007-12-12 | Univ Exeter | Plasmon resonance based sensor |
-
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Publication number | Priority date | Publication date | Assignee | Title |
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Non-Patent Citations (3)
Title |
---|
BAI B: "Artificial optical activity in chiral resonant nanogratings", PROCEEDINGS OF SPIE, vol. 7393, 25 November 2009 (2009-11-25), pages 73930K-1 - 73930K-11, XP055128840 * |
TAIKEI SUYAMA ET AL.: "Excitation of surface plasmons on metal grating and its application for refractive index measurement", THE INSTITUTE OF ELECTRICAL ENGINEERS OF JAPAN KENKYUKAI SHIRYO, 29 January 2007 (2007-01-29), pages 61 - 66, XP008172154 * |
TAIKEI SUYAMA ET AL.: "Surface Plasmon Resonance-absorption on a Metal Grating placed in Conical Mounting", THE PAPERS OF TECHNICAL MEETING ON ELECTROMAGNETIC THEORY, IEE JAPAN, 21 January 2005 (2005-01-21), pages 29 - 34, XP008172330 * |
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