JP2016004018A - Raman spectrometer and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a Raman spectrometer capable of detecting target substance with high sensitivity.SOLUTION: A Raman spectrometer 100 includes: a light source 10; an optical branch element 20 for branching the light emitted from the light source 10 into a plurality of light beams; a plurality of electric field enhancement elements 30 each having an irradiation region 35 which is irradiated with each of the plurality of branched light beams; and a photo-detector 60 for detecting the Raman scattered light radiated from the plurality of irradiation regions 35.

Description

  The present invention relates to a Raman spectroscopic device and an electronic apparatus.

In recent years, attention has been focused on surface enhanced Raman scattering (SERS) using surface plasmon resonance (SPR) as one of high-sensitivity spectroscopic techniques for detecting low-concentration detection molecules (target substances). Has been. SPR is an oscillation mode of an electron wave that causes coupling with light due to boundary conditions unique to the surface. The SERS, is enhanced electric field formed by the metal surface with the irregular structure of the nanometer scale, a spectroscopy can be detected with high sensitivity by Raman scattering light is 10 ^double 10 ¹⁴ fold enhancement. The detection molecule is irradiated with single-wavelength, linearly polarized excitation light such as a laser, and scattering (Raman scattered light) whose wavelength is shifted from the excitation light wavelength by the molecular vibration energy of the detection molecule is detected and fingerprint spectrum ( Raman spectrum). The detection molecule can be identified from the fingerprint spectrum.

  In the Raman spectroscopic device using SERS as described above, a technique is known in which light from a light source is split into a plurality of light beams and irradiated to an electric field enhancing element.

  For example, in Patent Document 1, one beam is split into a predetermined number by a beam splitting means arranged on a branch optical path, and each split beam is output as an irradiation beam for surface plasmon excitation. An apparatus is described. Patent Document 2 describes that simultaneous multipoint measurement is possible by using a beam splitter that uses a single laser beam as a light source and converts it into a number of parallel light beams.

JP 2006-258739 A JP 2006-3214 A

  However, the devices described in Patent Documents 1 and 2 detect light branched into a plurality of light using a plurality of photodetectors such as a line sensor and a photodiode array. Therefore, the apparatus described in Patent Documents 1 and 2 may be increased in size.

  One of the objects according to some aspects of the present invention is to provide a Raman spectroscopic device that can be miniaturized. Another object of some aspects of the present invention is to provide an electronic apparatus including the Raman spectroscopic device.

The Raman spectroscopic device according to the present invention is:
A light source;
An optical branching element that branches light emitted from the light source into a plurality of lights;
A plurality of the electric field enhancing elements each having an irradiation region irradiated with each of the plurality of branched light beams;
A photodetector for detecting Raman scattered light emitted from the plurality of irradiation regions;
including.

  Such a Raman spectroscopic device can be downsized as compared with the case where a plurality of photodetectors are included.

The Raman spectroscopic device according to the present invention is:
A light source;
An optical branching element that branches light emitted from the light source into a plurality of lights;
The electric field enhancing element having a plurality of irradiation regions irradiated with each of the plurality of branched light beams;
A photodetector for detecting Raman scattered light emitted from the plurality of irradiation regions;
including.

  Such a Raman spectroscopic device can be downsized as compared with the case where a plurality of photodetectors are included.

In the Raman spectroscopic device according to the present invention,
A Raman spectroscopic device capable of detecting a target substance,
The first reflection spectrum obtained when the first irradiation region of the plurality of irradiation regions is irradiated with white light has a Raman shift of the first peak due to the target substance in the Raman spectrum obtained from the Raman scattered light. Having an absorption region at a first wavelength corresponding to
The second reflection spectrum obtained when the second irradiation region of the plurality of irradiation regions is irradiated with white light is a Raman shift of the second peak due to the target substance in the Raman spectrum obtained from the Raman scattered light. May have an absorption region at the second wavelength corresponding to.

  In such a Raman spectroscopic device, the electric field can be enhanced by the electric field enhancing element at the first wavelength and the second wavelength. Thereby, in such a Raman spectroscopic device, a target substance can be detected with high sensitivity.

In the Raman spectroscopic device according to the present invention,
A Raman spectroscopic device capable of detecting a first target substance and a second target substance,
A first reflection spectrum obtained when white light is irradiated on the first irradiation region of the plurality of irradiation regions is a first peak due to the first target substance in the Raman spectrum obtained from Raman scattered light. Having an absorption region at the first wavelength corresponding to the Raman shift;
The second reflection spectrum obtained when the second irradiation region of the plurality of irradiation regions is irradiated with white light has a second peak caused by the second target substance in the Raman spectrum obtained from Raman scattered light. You may have an absorption area | region in the 2nd wavelength corresponding to a Raman shift.

  In such a Raman spectroscopic apparatus, even when a plurality of types of target substances are contained in the sample, the target substances can be detected simultaneously.

In the Raman spectroscopic device according to the present invention,
The first reflection spectrum has an absorption region at a wavelength of light emitted from the light source,
The second reflection spectrum may have an absorption region at a wavelength of light emitted from the light source.

  In such a Raman spectroscopic device, the electric field can be enhanced by the electric field enhancing element at the wavelength emitted from the light source. As a result, the Raman spectroscopic device can detect the target substance with higher sensitivity.

In the Raman spectroscopic device according to the present invention,
The optical branch element is:
A plurality of structures each including a first substrate that transmits light emitted from the light source and a reflective film that is provided on the first substrate and reflects at least part of the light emitted from the light source are stacked. It may be.

  In such a Raman spectroscopic device, for example, by changing the thickness of the reflective film, the intensity of light irradiated to the first irradiation area and the intensity of light irradiated to the second irradiation area can be changed. it can.

In the Raman spectroscopic device according to the present invention,
The electric field enhancing element is
A second substrate;
A metal layer provided on the second substrate;
A dielectric layer provided on the metal layer;
A plurality of metal microstructures provided on the dielectric layer;
You may have.

  In such a Raman spectroscopic device, for example, an electric field is generated by interacting a propagation surface plasmon excited at the interface between the metal layer and the dielectric layer and a localized surface plasmon excited by the metal microstructure. The electric field of the enhancement element can be enhanced.

In the Raman spectroscopic device according to the present invention,
A lens that collects Raman scattered light emitted from each of the plurality of irradiation regions may be included.

  In such a Raman spectroscopic device, Raman scattered light can be collected efficiently.

In the Raman spectroscopic device according to the present invention,
The photodetector has a spectroscopic element and a light receiving element,
The spectroscopic element may be an etalon.

  Such a Raman spectroscopic device can be reduced in size as compared with the case where the spectroscopic element is a diffraction grating type.

In the Raman spectroscopic device according to the present invention,
The light emitted from the light source may be light having a single wavelength and linearly polarized light.

In such a Raman spectroscopic device, the electronic device according to the present invention, which can detect a target substance with high sensitivity,
A Raman spectroscopic device according to the present invention;
A computing unit that computes health and medical information based on detection information from the photodetector;
A storage unit for storing the health care information;
A display unit for displaying the health care information;
including.

  Since such an electronic device includes the Raman spectroscopic device according to the present invention, the electronic device can be miniaturized.

The figure which shows typically the Raman spectroscopy apparatus which concerns on this embodiment. The figure which shows typically the optical branching element of the Raman spectroscopy apparatus which concerns on this embodiment. The top view which shows typically the electric field enhancement element of the Raman spectroscopy apparatus which concerns on this embodiment. Sectional drawing which shows typically the electric field enhancing element of the Raman spectroscopic device which concerns on this embodiment. The figure for demonstrating Raman spectroscopy. The figure for demonstrating a 1st reflection spectrum. The figure for demonstrating a 2nd reflection spectrum. The graph which shows the relationship between the diameter of a metal microstructure, and the wavelength of an absorption region. Sectional drawing which shows typically the manufacturing process of the electric field enhancement element of the Raman spectroscopy apparatus which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the electric field enhancement element of the Raman spectroscopy apparatus which concerns on this embodiment. The schematic block diagram of the optical interference exposure method using an ultraviolet laser. The figure which shows typically an example of the exposure pattern which can be produced with the optical interference exposure method. Sectional drawing which shows typically the manufacturing process of the electric field enhancement element of the Raman spectroscopy apparatus which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the electric field enhancement element of the Raman spectroscopy apparatus which concerns on this embodiment. The figure for demonstrating an etalon. An example of a functional block diagram of a Raman spectroscopic device concerning this embodiment. The figure which shows typically the Raman spectroscopy apparatus which concerns on the modification of this embodiment. 4A and 4B are diagrams for explaining an electronic apparatus according to the embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. Raman Spectroscopic Device First, a Raman spectroscopic device according to this embodiment will be described with reference to the drawings. FIG. 1 is a diagram schematically illustrating a Raman spectroscopic device 100 according to the present embodiment.

  As shown in FIG. 1, the Raman spectroscopic device 100 includes a light source 10, an optical branching element 20, an electric field enhancement element 30, a first lens 40, a second lens 50, a photodetector 60, and a flow path 70. And including. For convenience, in FIG. 1, the optical branch element 20, the electric field enhancing element 30, and the photodetector 60 are illustrated in a simplified manner.

1.1. Light source The light source 10 emits light. Light _{L IN} emitted from the light source 10 through the optical branching element 20, enters the field enhancement device 30. The light source 10 is, for example, a semiconductor laser or a gas laser, and the light _LIN is laser light. The light _LIN is light having a single wavelength and linearly polarized light. The wavelength of the light _{L IN} is, for example, 350nm or more 1000mn less, specifically a 632.8 nm. The light source 10 is supported by the support part 2, for example.

1.2. Optical branching element optical branching element 20, the light L _IN emitted from the light source 10 is branched into a plurality of light. In the illustrated example, the optical branching element 20 branches the light _LIN into five lights, but the number is not particularly limited. The optical branching element 20 is supported by the translucent part 3 of the support part 2, for example. The light transmitting portion 3 can transmit the light branched by the optical branching element 20. Here, FIG. 2 is a diagram schematically showing the optical branching element 20. As shown in FIG. 2, the optical branching element 20 is formed by laminating a plurality of structures 26 each having a translucent substrate (first substrate) 21 and a reflective film 25.

Structure 26 of the optical branch element 20 is stacked along the traveling direction of the light L _IN. The number of the structures 26 is not particularly limited, but is five in the illustrated example. For example, the number of the structures 26 is the same as the number of the electric field enhancing elements 30.

Translucent substrate 21 transmits light _{L IN.} The translucent substrate 21 includes a first surface 22 on which the light _LIN is incident, a second surface 23 facing the first surface 22 (parallel to the first surface 22), a first surface 22, and a second surface 23. And a third surface 24 for connecting the two. For example, the incident angle of the light _LIN on the first surface 22 is 45 °. The first surface 22 and the second surface 23 are optically polished. In the illustrated example, light incident from the first surface 22 is reflected by the second surface 23 and is emitted from the third surface 24. The material of the translucent substrate 21 is, for example, glass (specifically, quartz glass).

The reflective film 25 is provided on the second surface 23 of the translucent substrate 21. Reflective film 25, the second surface 23 can reflect at least part of the light _{L IN.} As the reflective film 25, for example, an Al film, an Au film having a Cr film as a base, an Ag film, a Pt film, a Cr film, or a dielectric multilayer film (such as a TiO ₂ film or a SiO ₂ film) is used.

By adjusting the thickness of the reflective film 25, the reflectance on the second surface 23 can be adjusted. Specifically, if the thickness of the reflective film 25 is increased, the reflectance on the second surface 23 is increased, and if the thickness of the reflective film 25 is decreased, the reflectance on the second surface 23 is decreased. In the illustrated example, a plurality of second surface 23, along the light traveling direction _{L IN,} the second surface 23a, second surface 23b, a second surface 23c, second surface 23d, in the order of the second surface 23e _Arranged and part of the light LIN is transmitted through the surfaces 23a, 23b, 23c, and 23d. The reflective film 25 provided on the surfaces 23a, 23b, 23c, and 23d is, for example, a half mirror.

Here, if the reflectances of the surfaces 23a, 23b, 23c, 23d, and 23e are R1, R2, R3, R4, and R5, respectively, the light reflected on each of the surfaces 23a, 23b, 23c, 23d, and 23e is reflected. The intensities I _RE1 , I _RE2 , I _RE3 , I _RE4 , and I _RE5 are expressed as the following formulas (1) to (5).

I _RE1 = R1 × I _IN (1)
I _RE2 = R2 × (I _IN −I _RE1 ) (2)
I _RE3 = R3 × (I _IN −I _RE1 −I _RE2 ) (3)
I _RE4 = R4 × (I _IN −I _RE1 −I _RE2 −I _RE3 ) (4)
I _RE5 = R5 × (I _IN −I _RE1 −I _RE2 −I _RE3 −I _RE4 ) (5)

In the Raman spectroscopic device 100, the values of the intensities I _RE1 , I _RE2 , I _RE3 , I _RE4 , and I _RE5 can be adjusted by adjusting the thickness of the reflective film 25. The intensities I _RE1 , I _RE2 , I _RE3 , I _RE4 , and I _RE5 may be equal to each other or different from each other.

  Although not shown, an antireflection film may be provided on the third surface 24. Thereby, light can be efficiently emitted from the third surface 24.

1.3. Electric field enhancement element 1.3.1. Configuration The electric field enhancing element 30 is irradiated with each of the light branched into a plurality. Here, FIG. 3 is a plan view schematically showing the electric field enhancing element 30. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3 schematically showing the electric field enhancing element 30. 3 and 4, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other.

  As shown in FIGS. 3 and 4, the electric field enhancing element 30 includes a support substrate (second substrate) 31, a metal layer 32, a dielectric layer 33, and a metal microstructure (metal nanoparticle) 34. Have. In the Raman spectroscopic device 100, the target substance is detected using the electric field enhancing element 30. The Raman spectroscopic device 100 can detect the target substance 1.

  The support substrate 31 is, for example, a glass substrate, a silicon substrate, or a resin substrate.

  The metal layer 32 is provided on the support substrate 31. The thickness of the metal layer 32 (size in the Z-axis direction) is, for example, not less than 10 nm and not more than 100 μm. The material of the metal layer 32 is, for example, gold, silver, copper, aluminum, platinum, nickel, palladium, tungsten, rhodium, or ruthenium. The metal layer 32 may have a function of exciting a propagation surface plasmon (PSP) in the electric field enhancement element 30. Specifically, PSP may be excited at the interface between the metal layer 32 and the dielectric layer 33 (in the vicinity of the interface) by making light (excitation light) incident on the electric field enhancement element 30.

The dielectric layer 33 is provided on the metal layer 32. The thickness of the dielectric layer 33 includes PSP excited at the interface between the metal layer 32 and the dielectric layer 33 and localized surface plasmon (LSP) excited by the metal microstructure 34. It may be set so that it can interact. The thickness of the dielectric layer 33 is not less than 20 nm and not more than 300 nm, for example. The material of the dielectric layer 33 is, for example, silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), tantalum oxide (Ta ₂ O ₅ ), silicon nitride (Si ₃ N ₄ ), titanium oxide (TiO ₂ ). It is.

The metal microstructure 34 is provided on the dielectric layer 33. The shape of the metal microstructure 34 is not particularly limited, and is, for example, a particle, a prism, a spheroid, or a spheroid, but in the illustrated example, a cylinder. The size of the metal fine structure 34 (e.g., X-axis direction size, and the Y-axis direction size) is less than the wavelength of light L _IN emitted from the light source 10. The size of the metal microstructure 34 is 10 nm or more and 1 μm or less, and preferably 80 nm or more and 150 nm or less. The thickness of the metal microstructure 34 is, for example, 1 nm or more and 500 nm or less, preferably 10 nm or more and 100 nm or less.

  A plurality of metal microstructures 34 are provided. The number of metal microstructures 34 is not particularly limited. In the illustrated example, the shapes of the plurality of metal microstructures 34 are the same as each other, but may be different from each other. In the illustrated example, the plurality of metal microstructures 34 are periodically provided in the X-axis direction and the Y-axis direction, but may not be provided periodically. The pitch in the X-axis direction of the metal microstructure 34 is, for example, not less than 20 nm and not more than 500 nm. The pitch in the Y-axis direction of the metal microstructure 34 is, for example, not less than 20 nm and not more than 500 nm. In the illustrated example, the pitch of the metal microstructures 34 in the X-axis direction is smaller than the pitch in the Y-axis direction, but may be the same as the pitch in the Y-axis direction.

  Note that the pitch in the X-axis direction of the metal microstructures 34 is the distance between the centers of gravity of the metal microstructures 34 adjacent in the X-axis direction. The pitch in the Y-axis direction of the metal microstructures 34 is the distance between the centers of gravity of the metal microstructures 34 adjacent in the Y-axis direction.

The material of the metal microstructure 34 is silver, gold, copper, aluminum, palladium, nickel, or platinum. These metals are metals having a small imaginary part of dielectric constant in the ultraviolet to visible light region, and can enhance the electric field enhancement effect. A target substance (target molecule) 1 to be detected is adsorbed on the metal microstructure 34.

  Although not shown, an adhesion layer for improving the adhesion between the dielectric layer 33 and the metal microstructure 34 may be provided between the dielectric layer 33 and the metal microstructure 34. That is, the metal microstructure 34 may be provided on the dielectric layer 33 via the adhesion layer. In addition, an adhesion layer for improving adhesion between the support substrate 31 and the metal layer 32 may be provided between the support substrate 31 and the metal layer 32. That is, the metal layer 32 may be provided on the support substrate 31 through the adhesion layer. Thus, in this specification, for example, the expression “the member B is provided on the member A” refers to the case where the member B is provided in contact with the member A and the case where the member B is provided. And the case where the member B is provided via another member. The adhesion layer is, for example, a chromium layer or a titanium layer.

  Here, FIG. 5A is a diagram for explaining Raman spectroscopy, and FIG. 5B is a diagram for explaining an enhanced electric field formed when light is irradiated on a metal microstructure (metal nanoparticle). FIG.

  Raman spectroscopy will be described with reference to FIG. When a target substance (target substance molecule) is irradiated with incident light (wavelength λ), most of the light is scattered as Rayleigh scattered light without changing its wavelength. Raman scattered light (wavelength λ−λ ′) partially containing information on molecular vibrations of the target substance is scattered. From the Raman scattered light, a fingerprint spectrum (Raman spectrum) of a target substance (here, acetaldehyde is taken as an example) is obtained. From this fingerprint spectrum, the detected substance can be identified as acetaldehyde. However, the Raman scattered light is very weak and it is difficult to detect a substance that exists only in a trace amount.

  Then, with reference to FIG.5 (b), the enhancement electric field formed when light is irradiated to the metal nanoparticle smaller than the wavelength of the incident light is demonstrated. When irradiating the metal nanoparticles with light, free electrons existing on the surface of the metal nanoparticles are affected by the electric field of the incident light and resonate. As a result of having the children aligned, an enhanced electric field stronger than the electric field of the incident light is formed. This phenomenon is a phenomenon peculiar to metal particles smaller than the wavelength of light, and is a phenomenon referred to as localized surface plasmon resonance (LSPR: LSPR: Localized Surface Plasson Resonance).

Next, surface-enhanced Raman scattering in the metal microstructure 34 will be described with reference to FIG. When Raman scattered light is generated in the enhanced electric field E, the phenomenon that the Raman scattered light is enhanced by the influence of the enhanced electric field E is surface enhanced Raman scattering (SERS). As shown in FIG. 4, the metal microstructure 34 is formed above the support substrate 31 and arranged so as to form an enhanced electric field E in the gap. Here, when the target substance 1 enters, the Raman scattered light is enhanced by the enhanced electric field E, and a strong Raman signal is obtained. As a result, Raman spectroscopy can be performed even with the target substance 1 present in a minute amount. Thereby, a trace amount of the target substance 1 can be detected with high sensitivity. In FIG. 4, incident light incident on the electric field enhancement element 30 is illustrated as L _IN , Rayleigh scattered light as L _RAY , and Raman scattered light as L _RAM .

  The electric field enhancing element 30 has an irradiation region 35 to which the light branched into a plurality of parts in the optical branching element 20 is irradiated. The irradiation region 35 is a region including the metal microstructure 34. That is, the electric field enhancing element 30 is irradiated from the metal microstructure 34 side.

As shown in FIG. 1, the electric field enhancing element 30 is provided on the inner wall 72 of the flow path 70. A plurality of electric field enhancing elements 30 are provided. In the illustrated example, five electric field enhancing elements 30 are provided, but the number is not particularly limited. The five electric field enhancing elements 30 are arranged in the order of the electric field enhancing elements 30a, 30b, 30c, 30d, and 30e along the direction in which the sample (gas sample or liquid sample) containing the target substance flows (arrow A direction shown in FIG. 1). Are arranged in Corresponding to the number of electric field enhancing elements 30, the number of structures 26 in the optical branching element 20 is determined. As shown in FIG. 1, a plurality of irradiation regions 35 are provided by providing a plurality of electric field enhancing elements 30. Each of the plurality of irradiation regions 35 is irradiated with each of a plurality of branched light beams. Specifically, as shown in FIG. 1, the light _LIN is branched into light L _IN 1, L _IN 2, L _IN 3, L _IN 4, and L _IN 5 in the optical branching element 20, respectively. Incident to 30a, 30b, 30c, 30d, 30e.

1.3.2. Next, the reflection spectrum (reflectance spectrum) in the irradiation region 35 of the electric field enhancing element 30 will be described with reference to the drawings. In the Raman spectroscopic device 100, the same reflection spectrum may be obtained in the plurality of irradiation regions 35, or reflection spectra having different shapes may be obtained.

  Hereinafter, a first reflection spectrum can be obtained in the irradiation region 35 of the electric field enhancement elements 30a, 30c, 30e (hereinafter also referred to as “first irradiation region 135”), and the irradiation region 35 of the electric field enhancement elements 30b, 30d. A case where the second reflection spectrum can be obtained in (hereinafter, also referred to as “second irradiation region 235”) will be described. The electric field enhancing elements 30a, 30c, 30e and the electric field enhancing elements 30b, 30d differ in the irradiation regions 135, 235 due to, for example, different parameters (for example, diameter in plan view) of the metal microstructure 34. A reflection spectrum can be obtained. In the example shown in FIG. 1, the first irradiation areas 135 and the second irradiation areas 235 are alternately arranged along the arrow A direction.

  FIG. 6 is a diagram for explaining the first reflection spectrum S1. FIG. 7 is a diagram for explaining the second reflection spectrum S2. The first reflection spectrum S1 is a reflection spectrum obtained when the first irradiation region (irradiation region of the electric field enhancing elements 30a, 30c, 30e) 135 of the plurality of irradiation regions 35 is irradiated with white light. The second reflection spectrum S2 is a reflection spectrum obtained when the second irradiation region (irradiation region of the electric field enhancing elements 30b and 30d) 235 among the plurality of irradiation regions 35 is irradiated with white light. As shown in FIGS. 6 and 7, the reflection spectra S1 and S2 are spectra in which the horizontal axis represents wavelength and the vertical axis represents reflectance. The reflection spectra S1 and S2 can be obtained, for example, in a state where the sample containing the target substance 1 is not exposed to the electric field enhancing element 30 (in a state where the target substance 1 is not attached to the electric field enhancing element 30).

  As shown in FIG. 6, the first reflection spectrum S1 has an absorption region. Specifically, the first reflection spectrum S1 has a first absorption region A1 and a second absorption region A2. The first absorption region A1 is an absorption region on the shorter wavelength side than the second absorption region A2. As shown in FIG. 7, the second reflection spectrum S2 has an absorption region. Specifically, the second reflection spectrum S2 has a third absorption region A3 and a fourth absorption region A4. The third absorption region A3 is an absorption region on the shorter wavelength side than the fourth absorption region A4.

  Here, the absorption region is a region where the reflection spectrum changes due to light absorption by SPR, specifically, a region where the reflectance of the reflection spectrum falls. In other words, when SPR occurs due to irradiation with excitation light (incident light), absorption due to resonance occurs, the reflectance decreases, and an absorption region appears. Therefore, the intensity of the enhanced electric field of SPR can be expressed by (1-r) using the reflectance r. Since there is a relationship that the intensity of the enhanced electric field is stronger as the value of the reflectance r is closer to zero, the reflectance can be used as an index of the intensity of the enhanced electric field of the SPR.

  Each of the reflection spectra S1 and S2 has two absorption regions because the PSP excited at the interface between the metal layer 32 and the dielectric layer 33 and the LSP excited by the metal microstructure 34 are electromagnetic. This is because they interact with each other and anti-crossing. In the example illustrated in FIG. 6, the first absorption region A1 is an absorption region having a larger half width than the second absorption region A2, and in the example illustrated in FIG. 7, the third absorption region A3 is more than the fourth absorption region A4. Is an absorption region with a small half-value width. An absorption region having a greater contribution of LSP than PSP tends to have a larger half width, and an absorption region having a greater contribution of PSP than LSP tends to have a smaller half width.

  Here, the absorption region will be described more specifically. Below, with reference to FIG. 6, it demonstrates using 1st absorption area | region A1. In addition, the absorption area | region which concerns on this invention is not limited to the content of the following description.

  The absorption region of the reflection spectrum is a portion having a point (minimum point) P at which the reflectance is minimized, and the reflectance is lower than the straight line (baseline) BL due to light absorption by SPR. is there. The base line BL has a local maximum point closest to the local minimum point P from the local minimum point P to the short wavelength side (a point at which the reflectivity reaches a local maximum) α and a local maximum point closest to the local minimum point P from the local minimum point P to the long wavelength side. This is a line connecting the points (points where the reflectance becomes maximum) β. The difference between the reflectance of the minimum point P and the reflectance of the intersection γ between the straight line L passing through the minimum point P and parallel to the vertical axis and the base line BL is, for example, 0.05 or more.

  When the local maximum point α is not present on the short wavelength side of the local minimum point P, the base line BL is the maximum point (the point at which the reflectivity is maximum) α ′ on the short wavelength side of the local minimum point P and the local maximum point. This is a line connecting β and. In addition, when there is no local maximum point β on the long wavelength side of the local minimum point P, the baseline BL has a local maximum point α and a maximum point on the long wavelength side of the local minimum point P (a point at which the reflectance becomes maximum) β. A line connecting ′ and ′. When the local maximum points α and β are not included, the base line BL is a line connecting the maximum point α ′ and the maximum point β ′. The same applies to the absorption regions A2, A3, and A4.

  As shown in FIG. 6, the first reflection spectrum S1 corresponds to the Raman shift of the first peak caused by the target substance 1 of the Raman spectrum obtained from the Raman scattered light (Raman scattered light emitted from the irradiation region 35). A first absorption region A1 is provided at the first wavelength λ1. As shown in FIG. 7, the second reflection spectrum S2 has a fourth absorption region A4 at the second wavelength λ2 corresponding to the Raman shift of the second peak caused by the target substance 1 of the Raman spectrum obtained from the Raman scattered light. Have.

Here, the Raman spectrum is a spectrum expressed as a Raman shift on the horizontal axis and an intensity on the vertical axis as shown in FIG. 5A, for example. The Raman spectrum can be obtained by Raman scattered light emitted from the electric field enhancing element 30 to which the target substance 1 is attached. The first peak and the second peak of the Raman spectrum are peaks characteristic of the target substance 1 that appear in the Raman spectrum. In the Raman spectrum, acetone in the case of _{((CH 3) 2 C =} O) is, 580 cm ^-1 vicinity, 787cm ^-1 near 1700 cm ^-1 vicinity, a peak near 2923cm ^-1 appears. Thus, among the peaks appearing in the Raman spectrum, the first peak may be the peak having the highest intensity, and the second peak may be the peak having the second highest intensity.

The first wavelength λ1 is a wavelength corresponding to the Raman shift of the first peak, and the second wavelength λ2 is a wavelength corresponding to the Raman shift of the second peak. Here, the “wavelength corresponding to the Raman shift” is the wavelength λ _S of the Raman scattered light calculated from the Raman shift ν based on the following formula (6). Incidentally, by the following equation (6), the lambda _IN is the wavelength of light incident on the irradiation region 35 (the wavelength of the light _{L IN).}

ν = ((1 / λ _IN ) − (1 / λ _S )) × 10 ⁷ (6)

In the example shown in FIG. 6, the first wavelength λ1 is 680 nm. In the example shown in FIG. 7, the second wavelength λ2 is 800 nm. Furthermore, the first reflection spectrum S1 has a first absorption area A1 to the wavelength of light L _IN emitted from the light source. The second reflection spectrum S2 has a third absorption region A3 on the wavelength of the light _{L IN.} In the example shown in FIGS. 6 and 7, the wavelength lambda _IN of the light _{L IN} is 632.8 nm.

In the first reflection spectrum S1, the wavelength lambda _IN of the first wavelength λ1 and the light _{L IN} are within the scope of the first absorbing region A1. In the first reflection spectrum S1, the reflectivity at the first wavelength .lambda.1, and reflectance at the wavelength of the light L _IN is a line segment connecting the γ reflectance (points P and at the height of half of the first absorbent region A1 Smaller than the reflectance at the middle point M (see FIG. 6). In the first reflection spectrum S1, the reflectivity at the first wavelength .lambda.1, and reflectance at a wavelength lambda _IN of the light _{L IN} is, for example, 0.4 or less.

In a second reflection spectrum S2, the wavelength lambda _IN of the light _{L IN} is within the scope of the third absorption region A3, the second wavelength λ2 is included in the scope of the fourth absorbent region A4. In a second reflection spectrum S2, the reflectivity at the second wavelength λ2 is smaller than the reflectance at half height of the fourth absorption region A4, the reflectance at the wavelength of the light L _IN is the third absorbent region A3 High Less than half of the reflectivity. Although not shown, the second reflection spectrum S2, the second wavelength λ2 may be a wavelength at the minimum point P of the fourth absorption region A4, the wavelength lambda _IN of the light L _IN is the minimum point of the third absorbing region A3 P The wavelength at may be used. In a second reflection spectrum S2, the reflectivity at the second wavelength .lambda.2, and reflectance at a wavelength lambda _IN of the light _{L IN} is, for example, 0.4 or less.

Here, the enhancement intensity I _SERS due to the surface-enhanced Raman effect is expressed by the following equation (7) according to the scattering cross section σ, the enhanced electric field E _{i of} incident light (excitation light), and the enhanced electric field E _s of Raman scattered light. expressed.

I _{SERS ∝σ} × E _i ² × E _s ² (7)

  Therefore, in order to obtain stronger enhancement, it is a condition that both the enhanced electric field of excitation light and the enhanced electric field of Raman scattered light become stronger.

In Raman spectroscopy apparatus 100, as described above, a characteristic peak of a target substance at a wavelength of the light L _IN lambda _IN, and Raman spectra, the wavelength λ1 corresponding to the first peak and second peak in .lambda.2, reflecting The electric field enhancing element 30 can be designed so that the spectra S1 and S2 have absorption regions. Accordingly, in the Raman spectroscopic device 100, the electric field can be enhanced by the electric field enhancing element 30 at the wavelengths λ _IN , λ1, and λ2, and the target substance can be detected with high detection sensitivity.

  In the above, the electric field enhancing elements 30a, 30c, 30e and the electric field enhancing elements 30b, 30d are different in the parameters of the metal microstructure 34, so that two types of reflection spectra (reflection spectra S1, S2) are obtained. Although the example obtained is described, the number of reflection spectra obtained from the plurality of electric field enhancement elements 30 is not particularly limited. For example, in the electric field enhancing elements 30a, 30b, 30c, 30d, and 30e, the parameters of the metal microstructure 34 may be different from each other to obtain five types of reflection spectra. In this case, the target substance can be detected with high sensitivity using five characteristic peaks of the target substance in the Raman spectrum.

  Further, the sample flowing into the flow path 70 may contain only one type of target substance, or may contain a plurality of target substances. When a sample includes a plurality of target substances, a plurality of target substances can be detected by one measurement (by one Raman spectroscopy). For example, when the sample includes two types of target substances (first target substance and second target substance), the first reflection spectrum S1 is caused by the first target substance of the Raman spectrum obtained from the Raman scattered light. The first absorption region A1 can be provided at the first wavelength λ1 corresponding to the Raman shift of the first peak. The second reflection spectrum S2 has a fourth absorption region A4 at the second wavelength λ2 corresponding to the Raman shift of the second peak caused by the second target substance of the Raman spectrum obtained from the Raman scattered light. For example, the first target substance is acetone and the second target substance is ethanol.

Further, in the Raman spectrum, in the case of ethyl alcohol _{(C 2 H 5 OH),} 433cm -1 near, 883cm ^-1 near 1275 cm ^-1 vicinity, a peak near 1453cm ^-1 appears. In the case of methyl alcohol _(CH 3 OH), 1035cm ^-1 vicinity 1104Cm ^-1 vicinity peak appears in the vicinity of 1457cm ^-1. In the case of pyridine _{(C 5 H} 5 N) is, 990 cm ^-1 vicinity, 1030 cm ^-1 vicinity peak appears in the vicinity of 1584 cm ^-1. In the case of aniline _{(C 6} H 5 NH ₂₎ is, 526cm ^-1 near, 996cm ^-1 near peak appears in the vicinity of 1593 cm ^-1. In the case of toluene (C ₆ H ₅ CH ₃ ), peaks appear in the vicinity of 787 cm ^{−1 and in the} vicinity of 1002 cm ⁻¹ . In the case of urea _{((H 2 N) 2 C} = O) is, 521 cm ^-1 vicinity, 999cm ^-1 near peak appears in the vicinity of 1156cm ^-1.

1.3.3. Next, the relationship between the diameter of the metal microstructure (diameter in plan view) and the wavelength of the absorption region will be described with reference to the drawings. FIG. 8 is a graph showing the relationship between the diameter of the metal microstructure and the wavelength of the absorption region. FIG. 8 is a graph obtained from simulation in electromagnetic field analysis (FDTD analysis).

The model M used in this simulation will be described. A metal layer (Au layer, thickness 100 nm) is provided on the support substrate, a dielectric layer (SiO ₂ layer, thickness 60 nm) is provided on the metal layer, and a metal microstructure (columnar Au) is provided on the dielectric layer. Particle M, thickness 30 nm) was provided as model M. In the model M, Au particles were periodically arranged in the X-axis direction and the Y-axis direction as shown in FIG. The pitch of Au particles in the X-axis direction was 140 nm, and the pitch of Au particles in the Y-axis direction was 600 nm. In such a model M, the wavelength of the minimum point of the absorption region in the reflection spectrum obtained by changing the diameter of the Au particles and irradiating with white light was plotted to obtain FIG.

  As shown in FIG. 8, it was found that the wavelength of the minimum point of the absorption region can be changed by changing the diameter of the Au particles. Therefore, it can be said that the electric field enhancing element can be designed by changing the diameter of the Au particles so that the reflection spectrum has an absorption region at a wavelength corresponding to the characteristic peak of the target substance in the Raman spectrum.

In FIG. 8, plots each asymptotic to two straight lines were obtained. A straight line L _PSP in which the wavelength is constant even when the thickness of the Au particle is changed indicates the resonance wavelength of the PSP. The straight line L _LSP whose wavelength changes as the thickness of the Au particle changes indicates the resonance wavelength of the LSP. The plot closer to the straight line L _LSP than the straight line L _PSP is a plot of the absorption region where the contribution of the LSP is greater than the contribution of the PSP. The plot closer to the straight line L _PSP than the straight line L _LSP is a plot of the absorption region where the contribution degree of the PSP is larger than the contribution degree of the LSP. For example, the contribution degree of LSP and the contribution degree of PSP are equal at the wavelength λ _M.

  Further, by changing not only the diameter of the Au particles but also other parameters of the members constituting the electric field enhancing element (for example, the thickness and pitch of the Au particles, the refractive index and the thickness of the dielectric layer 33), The wavelength of the minimum point of the absorption region can be changed.

1.3.4. Manufacturing Method Next, a manufacturing method of the electric field enhancing element 30 will be described with reference to the drawings. 9, 10, 13, and 14 are cross-sectional views schematically showing the manufacturing process of the electric field enhancing element 30.

  As shown in FIG. 9, a metal layer 32 is formed on the support substrate 31. The metal layer 32 is formed by, for example, a vacuum evaporation method or a sputtering method.

  Next, the dielectric layer 33 is formed on the metal layer 32. The dielectric layer 33 is formed by, for example, a vacuum deposition method, a sputtering method, or a CVD (Chemical Vapor Deposition) method.

  As shown in FIG. 10, a resist layer 9 is formed on the dielectric layer 33. The resist layer 9 is formed by applying and drying with an apparatus such as spin coating. The resist layer 9 is, for example, a positive resist layer. The thickness of the resist layer 9 is, for example, not less than 0.3 μm and not more than 1 μm.

  Next, the resist layer 9 is exposed by a light interference exposure method. Specifically, exposure is performed by an electron beam exposure method or an optical interference exposure method using an ultraviolet laser as an exposure apparatus. The electron beam exposure method has a high degree of freedom in exposure, but has a limit in mass productivity. Therefore, it is preferable to adopt an optical interference exposure method using an ultraviolet laser excellent in mass productivity.

  Here, FIG. 11 is a schematic configuration diagram of an optical interference exposure method using an ultraviolet laser. As shown in FIG. 11, an ultraviolet laser light source 101 having a wavelength of 266 nm capable of continuous oscillation (CW) and an output of 200 mW is used as the light source. The laser light emitted from the laser light source 101 is turned back by the mirror 103 via the shutter 102 and branched to both sides by the half mirror 104. Each of them is folded back by a mirror 103 through an objective lens 105 and a pinhole 106 to widen the beam. The spread ultraviolet laser is irradiated to the mask 107 to form interference fringes, and the substrate 130 (the substrate including the support substrate 31, the metal layer 32, and the dielectric layer 33) coated with the resist layer 9 is irradiated. At this time, various patterns can be exposed by the exposure configuration of the interference fringes. For example, the pattern of one mask 107 can be a lattice, and the pattern of the other mask 107 can also be a lattice. Various patterns can be formed according to the angle at which the two intersect, and the pattern can be reduced to half the laser wavelength. It is possible. Further, this exposure method is a highly productive exposure method because a relatively large substrate can be exposed at once. A latent image of both interference fringes is formed on the resist layer 9.

  The interference fringes in the mask 107 can be inspected by the monitor 109 via the half mirror 104 and the CCD camera 108.

  FIG. 12 is a diagram schematically showing an example of an exposure pattern that can be produced by the optical interference exposure method. 12A is a plan view, and FIG. 12B is a cross-sectional view taken along line BB in FIG. 12A. The pattern 120 is a pattern example having a one-dimensional structure, and the pattern 122 is a pattern example having a two-dimensional structure.

  As shown in FIG. 13, when a desired pattern is exposed, the resist layer 9 is developed to leave only necessary portions. Specifically, a necessary amount is etched by wet etching or dry etching, and a part of the resist layer 9 is removed.

  As shown in FIG. 14, a metal layer 34 a to be a metal microstructure 34 is formed on the dielectric layer 33 and the resist layer 9. The metal layer 34a is formed by, for example, a vacuum evaporation method or a sputtering method.

  As shown in FIG. 4, the resist layer 9 and the metal layer 34a on the resist layer 9 are removed by lift-off. The lift-off is performed using a solvent such as acetone. Thereby, the metal microstructure 34 can be formed.

  The electric field enhancing element 30 can be manufactured through the above steps.

1.4. Lens Light emitted from the irradiation region 35 of the electric field enhancing element 30 (light including Raman scattered light and Rayleigh scattered light) is incident on the first lens 40 as shown in FIG. A plurality of first lenses 40 are provided corresponding to the number of electric field enhancing elements 30. The first lens 40 is a condensing lens, and can condense light emitted from each of the plurality of irradiation regions 35 (from each of the electric field enhancing elements 30).

  The first lens 40 is, for example, a convex lens. In the illustrated example, the plurality of first lenses 40 constitute a first lens array 42. For example, the first lens array 42 is supported by the support unit 2. The material of the first lens array 42 is, for example, glass. The Raman scattered light enhanced by the electric field enhancing element 30 is scattered in various directions, but the distribution is the strongest in the regular reflection direction and becomes weaker as it is farther from there. The first lens 40 can efficiently collect the Raman scattered light.

  The light emitted from the first lens 40 enters the second lens 50. A plurality of second lenses 50 are provided corresponding to the number of first lenses 40. The second lens 50 can change the traveling direction of the light emitted from the first lens 40. For example, when an etalon is used as the spectroscopic element 64 of the photodetector 60, it is necessary to make light incident perpendicularly to the reflecting mirror (half mirror). In the Raman spectroscopic device 100, the second lens 50 allows light to enter the etalon reflecting mirror vertically.

  The second lens 50 is, for example, a concave lens. In the illustrated example, the plurality of second lenses 50 form a second lens array 52. For example, the second lens array 52 is supported by the support unit 2. The material of the second lens array 52 is, for example, glass. The light emitted from the second lens 50 reaches the photodetector 60.

1.5. Photodetector The photodetector 60 detects Raman scattered light emitted from the plurality of irradiation regions 35 (from the electric field enhancing element 30). Only one photodetector 60 is provided. The photodetector 60 includes, for example, an optical filter 62, a spectroscopic element 64, and a light receiving element 66.

Light emitted from the second lens 50 enters the optical filter 62. The optical filter 62 is capable of removing Rayleigh scattered light having the same wavelength as light L _IN. The optical filter 62 is, for example, a band stop filter.

  The light emitted from the optical filter 62 is incident on the spectroscopic element 64. The spectroscopic element 64 is, for example, an etalon (wavelength variable etalon). The etalon is a mechanism that transmits only light having a wavelength resonated by a Fabry-Fellow resonator, and can be dispersed by changing the gap of the Fabry-Fellow resonator to change the wavelength of transmitted light.

  Here, FIG. 15 is a diagram for explaining the etalon. The principle of the wavelength tunable etalon will be described with reference to FIG.

The principle of spectroscopy is based on the fact that “the transmission wavelength condition is the principle of interference that is an integral multiple of the optical path difference between adjacent transmitted lights”, and only the wavelength satisfying the following equation (8) is transmitted. Only light with a wavelength can be extracted. The transparent base materials 601 and 602 having refractive indexes n ₁ and n ₂ are opposed in parallel, and half mirrors 603 and 604 are formed on the inner sides of both of them, and the inner side of the half mirrors 603 and 604 is n = 1. Keep it in a state (air, etc.). The light incident at the incident angle θ from the refractive index n1 side is reflected by the half mirrors 603 and 604 and reciprocates between the air gaps d. At that time, only light having a wavelength satisfying the condition of the following formula (8) is transmitted to the opposite side.
2d cos θ = λ _peak × n (8)

Here, d is an air gap (distance between the half mirrors 603 and 604), θ is an incident angle, n is a refractive index, and λ _peak is a wavelength of transmitted light. Spectroscopy is possible by making the air gap d variable.

FIG. 15B is a diagram for explaining the structure of an electrostatic actuator type wavelength tunable etalon (spectral element) 64. The upper substrate 641 and the lower substrate 642 are bonded at the bonding portion 643. There is an area through which light is transmitted in the central part of the substrates 641 and 642, and an electrostatic actuator part 644 for changing the air gap d is arranged around the area. Half mirrors 645 and 646 are formed in the central light transmission portion on the inner sides of the substrates 641 and 642 facing each other, and are arranged in parallel. The electrostatic actuator unit 644 is formed so that the electrodes 647 are opposed to each other, and when a voltage is applied to both, an electrostatic attraction force acts, and the rigidity of the electrostatic actuator unit 644 is deformed, so that the half mirror The air gap d in the portions 645 and 646 is reduced. By controlling this voltage, the air gap d can be controlled, and as a result, the wavelength of transmitted light is controlled. Figure 15 (b), the illustrates the light _{L A} incident on the etalon 64, the light transmitted through the etalon 64 as _{L B.}

  The etalon type is advantageous for miniaturization because the optical path length is shorter than that of the diffraction grating type. The wavelength variable etalon 64 can be enclosed in a vacuum package in order to quickly attenuate the residual vibration during the variable operation of the electrostatic actuator unit 644. The diaphragms of the substrates 641 and 642 are processed to be extremely thin. When the driving voltage is changed to change the air gap d, if an air (air) remains inside, the electrostatic actuator is used for its fluid resistance. The residual vibration of the portion 644 is attenuated slowly, and as a result, the time for spectral separation becomes long. In order to ensure long-term reliability of the half mirrors 645 and 646, it is desirable to keep the vacuum.

  FIG. 15C is a graph showing an example of optical characteristics of the wavelength tunable etalon when the drive voltage of the electrostatic actuator is changed. It can be seen that the wavelength at which the transmittance reaches a peak is changed to 700 nm, 600 nm, 500 nm, and 400 nm. Spectroscopy can be performed by gradually changing the drive voltage little by little. The half-value width of this spectrum greatly depends on the material of the mirror of the Fabry-Perot resonator. For example, an Ag alloy, a dielectric multilayer film, or the like can be selected depending on the application.

The light receiving element 66 receives the light split by the spectroscopic element 64. Specifically, the light received by the light receiving element 66 is converted into an electrical signal, whereby a Raman spectrum specific to the detection substance (target substance) can be obtained. For example, it is possible to specify what the target substance is by comparing the characteristic peak wavelength for each target substance with data stored in advance. Further, the concentration of the target substance can be calculated by comparing the signal intensity of the characteristic peak with the calibration curve data stored in advance. For example, a photodiode is used as the light receiving element 66.

1.6. As shown in FIG. 1, the flow path 70 has an inlet 74 through which a sample (a gas sample or a liquid sample) containing a target substance flows and an outlet 76 through which a gas sample containing the target substance flows out. doing. The channel 70 is, for example, a tubular member, and the electric field enhancing element 30 is provided on the inner wall 72 of the channel 70. An opening 78 is provided in the flow path 70, and light can be incident on the electric field enhancement element 30 through the opening 78, and light emitted from the electric field enhancement element 30 is incident on the photodetector 60. Can be made.

  When a suction means (not shown) outside the outlet 76 of the flow path 70 is operated, the pressure in the flow path 70 becomes negative, and the sample containing the target substance is sucked from the inlet 74 and introduced into the flow path 70. The For example, a dust removal filter (not shown) is provided at the inlet 74, and relatively large dust, a part of water vapor, and the like are removed. The sample containing the target substance is discharged from the outlet 76 via the electric field enhancing element 30 in the flow path 70. At that time, the target substance to be detected passes near the surface of the electric field enhancement element 30 and is adsorbed on the surface of the electric field enhancement element 30 to be detected. With respect to the shape of the flow path 70 for sucking and discharging the sample containing the target substance, the external light does not enter the electric field enhancing element 30 and the fluid resistance to the gaseous sample is reduced. It has been taken into account. The sample containing the target substance may be in contact with the lens arrays 42 and 52 but is not in contact with the photodetector 60.

1.7. Functional Block Diagram of Raman Spectrometer FIG. 16 is an example of a functional block diagram of the Raman spectrometer 100. When the Raman spectroscopic device 100 is turned on, the initial state is confirmed, and when the display indicating that the initial state is OK is displayed, the operator who sees it displays an instruction signal for starting detection from the operation panel 204. It outputs to CPU (Central Processing Unit) 201 of the signal processing control unit 200.

  When the CPU 201 receives an instruction signal for starting detection, the light source driving circuit 210 first outputs a light source operation signal to operate the light source 10. The light source 10 includes a temperature sensor and a light quantity sensor, and determines whether the information is sent to the CPU 201 and is stable. If the determination is OK, the process proceeds to the next.

  Next, in order to guide the sample containing the target substance to be detected to the vicinity of the surface of the electric field enhancing element 30 (see FIG. 1), a signal for operating the suction means 80 is sent from the CPU 201 to the suction means drive circuit 280, The sample containing the target substance is discharged from the suction port (inlet 74) through the flow path 70 (see FIG. 1) to the outside.

Next, the light source 10 is driven by the light source driving circuit 210 in accordance with a signal from the CPU 201 to emit light. This light is branched by the optical branching element 20 (see FIG. 1) and irradiated to the plurality of electric field enhancing elements 30. An enhanced electric field is excited in the vicinity of the metal microstructure 34 of each electric field enhancing element 30. Rayleigh scattered light and Raman scattered light radiated from the target substance are enhanced by the enhanced electric field, and the lenses 40 and 50 (see FIG. 1), the optical filter 62 (see FIG. 1) for blocking the Rayleigh light, and the spectroscopic element 64. Then, the light enters the light receiving element 66. By passing through the optical filter 62 for blocking Rayleigh scattered light, only the surface-enhanced Raman scattered light enters the spectroscopic element 64. When a wavelength tunable etalon using Fabro-Perry resonance is adopted as the spectroscopic element 64, the band of transmitted light (λ _{A to} λ _B ) and the half width are set, and the half width starts from λ _A by varying the wavelength of sequentially transmitted, lambda light intensity signal of the received the half-width at a repetition receiving element 66 to _B, then converted into an electric signal in the light receiving circuit 266, and outputs to the signal processing control unit 200. Specifically, a signal is output from the CPU 201 to the wavelength tunable etalon driving circuit 264, and the wavelength applied by the wavelength tunable etalon driving circuit 264 is changed to change the wavelength to be transmitted. . By doing in this way, the spectrum of the detected SERS light (Raman scattered light) will be obtained.

  The spectrum of the SERS light of the target substance obtained as described above is compared with, for example, spectrum data stored in a ROM (Read Only Memory) 203 of the signal processing control unit 200 to determine whether the target substance is a target substance. Determine and identify the substance. In order to notify the operator of the determination result on the spot, the result information is displayed on the display unit 205 from the CPU 201. When the obtained substance specifying result is transmitted as information to the outside, it is sent from the connection unit 207 based on a predetermined interface 206 standard. Note that the signal processing control unit 200 may include a RAM (Random Access Memory) 202 as shown in FIG.

  As the power supply unit 90, a primary battery, a secondary battery, or the like can be used. In the case of a primary battery, the CPU 201 compares the information stored in the ROM 203 with the voltage information of the obtained primary battery, and if the voltage is less than the specified voltage, the battery is replaced. Display. The operator can see the display and replace the primary battery and use it again. In the case of a secondary battery, the CPU 201 compares the information stored in the ROM 203 with the voltage information of the obtained secondary battery to indicate that the voltage is lower than the specified voltage. do. The operator sees the display and connects the charger to the connection unit 208 to charge the battery until it reaches a specified voltage and can use it repeatedly.

  The Raman spectroscopic device 100 has the following features, for example.

  A light source 10, an optical branch element 20 that branches light emitted from the light source 10 into a plurality of lights, and a plurality of electric field enhancement elements 30 each having an irradiation region 35 irradiated with each of the plurality of light branches. And a photodetector 60 that detects Raman scattered light emitted from the plurality of irradiation regions 35. As described above, the Raman spectroscopic device 100 includes only one photodetector 60. Therefore, the Raman spectroscopic device 100 can be downsized as compared with a case where a plurality of photodetectors are included. Furthermore, since the photodetector is a relatively expensive member, the Raman spectroscopic device 100 can achieve cost reduction as compared with the case where a plurality of photodetectors are included.

  Furthermore, since the Raman spectroscopic device 100 includes a plurality of electric field enhancement elements 30, for example, when a part of the electric field enhancement element 30 deteriorates, only the electric field enhancement element 30 having the deteriorated part can be replaced. it can. For example, as in a Raman spectroscopic device 300 described later (see FIG. 17), when one electric field enhancing element 30 having a plurality of irradiation regions 35 is provided, when a part of the electric field enhancing element 30 deteriorates, The electric field enhancing element 30 having a large area must be replaced, which may increase the cost.

  Note that the Raman spectroscopic device 100 does not include a plurality of light sources 10. Therefore, the Raman spectroscopic device 100 can detect the target substance more accurately than in the case where a plurality of light sources are provided. For example, when there are a plurality of light sources, if the wavelength of each monochromatic light source is slightly different, the wavelength of the Raman scattered light to be detected is also shifted, and accurate detection may not be possible. This is because Raman spectroscopy obtains a spectrum using a wavelength shift from the excitation light as a Raman shift, and variations in the excitation light become variations in the Raman shift.

In the Raman spectroscopic device 100, the first reflection spectrum S1 obtained when the first irradiation region 135 of the plurality of irradiation regions 35 is irradiated with white light is caused by the target substance 1 of the Raman spectrum obtained from the Raman scattered light. The second wavelength obtained by irradiating the second irradiation region 235 of the plurality of irradiation regions 35 with white light at the first wavelength λ1 corresponding to the Raman shift of the first peak. The reflection spectrum S2 has a fourth absorption region A4 at the second wavelength λ2 corresponding to the Raman shift of the second peak caused by the target substance 1 of the Raman spectrum obtained from the Raman scattered light. Therefore, in the Raman spectroscopic device 100, the electric field can be enhanced by the electric field enhancing element 30 at the wavelengths λ1 and λ2. Thereby, in the Raman spectroscopic device 100, the target substance can be detected with higher sensitivity than in the case where the absorption region is provided only in one of the first wavelength λ1 and the second wavelength λ2.

  Further, in the Raman spectroscopic device 100, when the sample includes a plurality of, for example, two types of target substances (first target substance and second target substance), the first irradiation in the plurality of irradiation regions 35 is performed. The first reflection spectrum S1 obtained when the region 135 is irradiated with white light has a first wavelength λ1 corresponding to the Raman shift of the first peak due to the first target substance in the Raman spectrum obtained from the Raman scattered light. The second reflection spectrum S2 that has the first absorption region A1 and is obtained when the second irradiation region 235 of the plurality of irradiation regions 35 is irradiated with white light is the second of the Raman spectrum obtained from the Raman scattered light. The fourth absorption region A4 is provided at the second wavelength λ2 corresponding to the Raman shift of the second peak caused by the target substance. Therefore, the Raman spectroscopic device 100 can simultaneously detect the target substance (the first target substance and the second target substance) even when a plurality of types of target substances are included in the sample.

In Raman spectroscopy apparatus 100, the first reflection spectrum S1 has a first absorbing region A1 to the wavelength lambda _IN of the light _{L IN} emitted from the light source 10, a second reflection spectrum S2, the light emitted from the light source 10 The third absorption region A3 is provided at the wavelength λ _{IN of} L _IN . Therefore, the Raman spectrometer 100, the wavelength lambda _IN, it is possible to enhance the electric field by the electric field enhancement device 30. As a result, the Raman spectroscopic device 100 can detect the target substance with higher sensitivity.

In Raman spectroscopy apparatus 100, the optical branching element 20 includes a light-transmitting substrate 21 to transmit light _{L IN} emitted from the light source 10, at least part of the light _{L IN} emitted from the light source 10 provided on the translucent substrate 21 A plurality of structures 26 each having a reflective film 25 that reflects light is laminated. Therefore, in the Raman spectroscopic device 100, for example, by changing the thickness of the reflective film 25, the intensity of light irradiated to the first irradiation area 135 and the intensity of light irradiated to the second irradiation area 235 are set. Can be changed. For example, as shown in FIGS. 6 and 7, when the reflectance at the first wavelength λ 1 is smaller than the reflectance at the second wavelength λ 2, the thickness of the reflective film 25 that reflects light toward the first irradiation region 135 is set. By making the thickness larger than the thickness of the reflective film 25 that reflects light toward the second irradiation region 235, the peak intensity of the Raman shift corresponding to the first wavelength λ1 can be increased.

  In the Raman spectroscopic device 100, the electric field enhancement element 30 is formed on the support substrate 31, the metal layer 32 provided on the support substrate 31, the dielectric layer 33 provided on the metal layer 32, and the dielectric layer 33. A plurality of metal microstructures 34 provided. Therefore, in the Raman spectroscopic device 100, for example, the PSP excited at the interface between the metal layer 32 and the dielectric layer 33 and the LSP excited by the metal microstructure 34 are allowed to interact with each other, thereby The electric field can be enhanced.

  The Raman spectroscopic device 100 includes a lens 40 that collects Raman scattered light emitted from each of the plurality of irradiation regions 35. As a result, the Raman spectroscopic device 100 can efficiently collect the Raman scattered light.

  In the Raman spectroscopic device 100, the photodetector 60 includes a spectroscopic element 64 and a light receiving element 66, and the spectroscopic element 64 is an etalon. Therefore, the Raman spectroscopic device 100 can be downsized as compared with the case where the spectroscopic element is a diffraction grating type.

  In the above example, the electric field enhancement elements 30a, 30c, and 30e and the electric field enhancement elements 30b and 30d have different reflections in the irradiation regions 135 and 235 due to different parameters of the metal microstructure 34, for example. The example which can obtain a spectrum (1st reflection spectrum S1, 2nd reflection spectrum S2) was demonstrated. However, in the Raman spectroscopic device according to the present invention, for example, the parameters such as the metal microstructures of the plurality of electric field enhancing elements may be the same, and the same reflection spectrum may be obtained. In this case, in the Raman spectroscopic device according to the present invention, since a plurality of irradiation regions 35 are provided, the area of the irradiation region 35 can be increased as compared with the case where there is one irradiation region 35. Therefore, for example, even when the concentration of the target substance in the sample is low and the adsorption probability of the target substance to the irradiation area 35 is small, the Raman scattered light from each irradiation area 35 can be integrated, and the target substance is highly sensitive. Can be detected.

2. Next, a Raman spectroscopic device according to a modification of the present embodiment will be described with reference to the drawings. FIG. 17 is a diagram schematically showing a Raman spectroscopic device 300 according to a modification of the present embodiment. Hereinafter, in the Raman spectroscopic device 300 according to the modified example of the present embodiment, differences from the example of the Raman spectroscopic device 100 according to the present embodiment will be described, and description of similar points will be omitted.

  In the Raman spectroscopic device 100 described above, as shown in FIG. 1, the electric field enhancing element 30 has one irradiation region 35, and a plurality of electric field enhancing elements 30 are provided.

  On the other hand, in the Raman spectroscopic device 300, as shown in FIG. 17, one electric field enhancing element 30 is provided, and the electric field enhancing element 30 has a plurality of irradiation regions irradiated with each of a plurality of branched light beams. 35. In the illustrated example, the electric field enhancing element 30 has five irradiation regions 35.

  In the Raman spectroscopic device 300, the first lens 40 and the second lens 50 do not constitute a lens array, and are provided one by one. Raman scattered light radiated from the plurality of irradiation regions 35 enters one first lens 40. The light emitted from the first lens 40 enters the second lens 50.

  The Raman spectroscopic device 300 can be miniaturized in the same manner as the Raman spectroscopic device 100.

3. Next, an electronic device 400 according to the present embodiment will be described with reference to the drawings. FIG. 18 is a diagram schematically illustrating an electronic apparatus 400 according to the present embodiment. The electronic apparatus 400 can include a Raman spectroscopic device according to the present invention. Hereinafter, an example including the Raman spectroscopic device 100 as a Raman spectroscopic device according to the present invention will be described.

  As shown in FIG. 18, the electronic apparatus 400 includes a Raman spectroscopic device 100, a calculation unit 410 that calculates health and medical information based on detection information from the photodetector 60, and a storage unit 420 that stores health and medical information. A display unit 430 for displaying health and medical information.

The calculation unit 410 is, for example, a personal computer, a portable information terminal (PDA: Per
(Sonical Digital Assistance) and receives detection information (signals, etc.) transmitted from the photodetector 60. The calculation unit 410 calculates health care information based on the detection information from the photodetector 60. The calculated health and medical information is stored in the storage unit 420.

  The storage unit 420 is, for example, a semiconductor memory, a hard disk drive, or the like, and may be configured integrally with the calculation unit 410. The health care information stored in the storage unit 420 is sent to the display unit 430.

  The display unit 430 includes, for example, a display board (liquid crystal monitor or the like), a printer, a light emitter, a speaker, and the like. The display unit 430 displays or issues information based on the health care information calculated by the calculation unit 410 so that the user can recognize the contents.

  The health information includes the presence or amount of at least one biological substance selected from bacteria, viruses, proteins, nucleic acids, and antigens / antibodies, or at least one compound selected from inorganic molecules and organic molecules. Information about can be included.

  The electronic apparatus 400 includes the Raman spectroscopic device 100. Therefore, the electronic device 400 can be downsized.

  The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine each embodiment and each modification.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1 Target substance, 2 Support part, 3 Light transmission part, 9 Resist layer, 10 Light source, 20 Optical branching element, 21 Light transmission board | substrate, 22 1st surface, 23, 23a, 23b, 23c, 23d, 23e 2nd surface, 24, 3rd surface, 25 reflective film, 26 structure, 30, 30a, 30b, 30c, 30d, 30e electric field enhancing element, 31 support substrate, 32 metal layer, 33 dielectric layer, 34 metal microstructure, 34a metal layer , 35 Irradiation area, 40 First lens, 42 First lens array, 50 Second lens, 52 Second lens array, 60 Photo detector, 62 Optical filter, 64 Spectroscopic element, 66 Light receiving element, 70 Flow path, 72 Inner wall , 74 inlet, 76 outlet, 78 opening, 80 suction means, 90 power supply unit, 101 laser light source, 102 shutter, 103 mirror, 104 half mirror, 105 objective 'S, 106 pinhole, 107 masks, 108 CCD camera, 109 monitor, 120 and 122 patterns, 130 the substrate, 135 a first irradiation region, 200 the signal processing control unit, 201 CPU, 202 RAM, 203 ROM, 204 operation panel, 205
Display unit, 206 interface, 207, 208 connection unit, 210 light source driving circuit, 235 second irradiation region, 264 wavelength variable etalon driving circuit, 266 light receiving circuit, 280 suction means driving circuit, 300 Raman spectroscopic device, 400 electronic device, 410 Arithmetic unit, 420 storage unit, 430 display unit, 601, 602 transparent base material, 603, 604 half mirror, 641 upper substrate, 642 lower substrate, 643 joint unit, 644 electrostatic actuator, 645, 646 half mirror, 647 electrode

Claims (11)

A light source;
An optical branching element that branches light emitted from the light source into a plurality of lights;
A plurality of the electric field enhancing elements each having an irradiation region irradiated with each of the plurality of branched light beams;
A photodetector for detecting Raman scattered light emitted from the plurality of irradiation regions;
Including a Raman spectroscopic apparatus. A light source;
An optical branching element that branches light emitted from the light source into a plurality of lights;
The electric field enhancing element having a plurality of irradiation regions irradiated with each of the plurality of branched light beams;
A photodetector for detecting Raman scattered light emitted from the plurality of irradiation regions;
Including a Raman spectroscopic apparatus. In claim 1 or 2,
A Raman spectroscopic device capable of detecting a target substance,
The first reflection spectrum obtained when the first irradiation region of the plurality of irradiation regions is irradiated with white light has a Raman shift of the first peak due to the target substance in the Raman spectrum obtained from the Raman scattered light. Having an absorption region at a first wavelength corresponding to
The second reflection spectrum obtained when the second irradiation region of the plurality of irradiation regions is irradiated with white light is a Raman shift of the second peak due to the target substance in the Raman spectrum obtained from the Raman scattered light. Raman spectrometer having an absorption region at the second wavelength corresponding to. In claim 1 or 2,
A Raman spectroscopic device capable of detecting a first target substance and a second target substance,
A first reflection spectrum obtained when white light is irradiated on the first irradiation region of the plurality of irradiation regions is a first peak due to the first target substance in the Raman spectrum obtained from Raman scattered light. Having an absorption region at the first wavelength corresponding to the Raman shift;
The second reflection spectrum obtained when the second irradiation region of the plurality of irradiation regions is irradiated with white light has a second peak caused by the second target substance in the Raman spectrum obtained from Raman scattered light. A Raman spectroscopic device having an absorption region at a second wavelength corresponding to a Raman shift. In any one of Claims 1 thru | or 4,
The first reflection spectrum has an absorption region at a wavelength of light emitted from the light source,
The second reflection spectrum is a Raman spectroscopic device having an absorption region at a wavelength of light emitted from the light source. In any one of Claims 1 thru | or 5,
The optical branch element is:
A plurality of structures each including a first substrate that transmits light emitted from the light source and a reflective film that is provided on the first substrate and reflects at least part of the light emitted from the light source are stacked. The Raman spectrometer. In any one of Claims 1 thru | or 6,
The electric field enhancing element is
A second substrate;
A metal layer provided on the second substrate;
A dielectric layer provided on the metal layer;
A plurality of metal microstructures provided on the dielectric layer;
A Raman spectroscopic apparatus. In any one of Claims 1 thru | or 7,
A Raman spectroscopic device including a lens that collects Raman scattered light emitted from each of the plurality of irradiation regions. In any one of Claims 1 thru | or 8,
The photodetector has a spectroscopic element and a light receiving element,
The Raman spectroscopic device, wherein the spectroscopic element is an etalon. In any one of Claims 1 thru | or 9,
The light emitted from the light source is a Raman spectroscopic device having a single wavelength and linearly polarized light. The Raman spectroscopic device according to any one of claims 1 to 10,
A computing unit that computes health and medical information based on detection information from the photodetector;
A storage unit for storing the health care information;
A display unit for displaying the health care information;
Including electronic equipment.