JP2003215029A - Apparatus for measuring surface plasmon resonance, and apparatus for measuring surface plasmon resonance and optical absorption spectrum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for measuring surface plasmon resonance capable of performing measurement in addition to the phenomenon of surface plasmon resonance, to be concrete, measurement on optical absorption spectra in the same apparatus and provide an apparatus for measuring surface plasmon resonance and optical absorption spectra capable of actually measuring both surface plasmon resonance and optical absorption spectra. <P>SOLUTION: The surface plasmon resonance measuring apparatus is provided with a slab- type waveguide comprised of a slab-type transparent substrate on which a metal membrane is formed, a light source means constituted in such a way as to introduce white light to the slab-type waveguide via an optical fiber, and a light detecting means for detecting and analyzing light emergent from the slab-type waveguide after transmitting through the slab-type waveguide. A sample is arranged on the metal membrane, and the white light is made incident into the slab-type waveguide and transmit through the slab-type waveguide through the use of the light source means. A surface plasmon phenomenon is brought about in the metal membrane, on which the sample is arranged, to detect spectral changes of the white light due to the surface plasmon phenomenon from light emergent from the slab-type waveguide through the use of the light detecting means. From the results of detection, the refractive index of the sample is measured. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface plasmon resonance sensor configured to measure the refractive index of a sample by using a slab type waveguide.

[0002]

2. Description of the Related Art Conventionally, it has been proposed to measure the state of a substance by utilizing the surface plasmon resonance phenomenon generated on the surface of a metal thin film such as gold or silver. The surface plasmon is a type of compressional wave of electrons generated at a metal-dielectric interface, and its wave number changes depending on the thickness of the sample and optical characteristics (dielectric constant, refractive index). Since this change cannot be measured directly, in the measurement method using surface plasmon resonance, a metal thin film is formed by depositing a metal such as gold or silver on the bottom surface of the prism, and the sample is directly attached to the surface of the metal thin film. In the contact state, light of a tungsten lamp, a halogen lamp, a light emitting diode (LED), a super luminescent diode (SLD), a laser or the like is applied to the back surface of the metal thin film,
That is, an evanescent wave is generated by applying it from the opposite surface of the sample, and a change in the refractive index is measured from the change in the angle of the dark line caused by the extinction caused by the resonance of the evanescent wave with the surface plasmon. It is a general method to indirectly measure the change in the state of the sample that is brought into contact with the surface.

[0003]

Recently, it has been shown that surface plasmon resonance measurement based on light absorption change is very effective in bio / chemical sensing and material evaluation. In that case, since the conventional surface plasmon resonance sensor device described above is designed as a device for measuring the real part change of the refractive index, a surface plasmon resonance sensor based on the principle of measuring the complex refractive index change due to light absorption change is used. Had a problem that it was not always designed properly. In consideration of the above-mentioned problems, the inventors have proceeded with research on surface plasmon resonance measurement capable of performing measurement related to light absorption with the same device, in addition to the surface plasmon resonance phenomenon, and came to invent the present invention. It was The present invention provides a measurement related to light absorption other than the surface plasmon resonance phenomenon, specifically, a surface plasmon resonance measurement apparatus and an actual surface plasmon resonance measurement that enable measurement of a light absorption spectrum in the same apparatus. It is an object of the present invention to provide a surface plasmon resonance and optical absorption spectrum measurement device capable of measuring both the optical absorption spectrum measurement and the optical absorption spectrum measurement.

[0004]

In order to achieve the above object, a surface plasmon resonance measuring apparatus according to the present invention comprises:
A slab-type waveguide formed of a slab-type transparent substrate on which a metal thin film is formed, a light source means configured to introduce white light into the slab-type waveguide through an optical fiber, and the slab-type waveguide A light detecting means for detecting and analyzing the light emitted from the slab-type waveguide after propagating in the sample, and placing a sample on the metal thin film, and using the light source means to produce white light in the slab-type waveguide. Light is incident to propagate through the slab-type waveguide to generate a surface plasmon phenomenon in the metal thin film on which the sample is placed, and the light emitted from the slab-type waveguide using the photodetection means causes white color due to the surface plasmon phenomenon. It is characterized in that the spectral change of light is detected and the refractive index of the sample is measured from the detection result. Further, the surface plasmon resonance and optical absorption spectrum measuring apparatus according to the present invention is configured to introduce a white light into the slab type waveguide through an optical fiber, and a measuring section to which the slab type waveguide can be detachably attached. The light source means and the light detecting means for detecting and analyzing the light emitted from the slab-type waveguide after propagating in the slab-type waveguide, and the measuring unit having a metal thin film layer, A slab waveguide for surface plasmon resonance measurement consisting of a slab-type transparent substrate configured so that a sample can be placed on a metal thin film, and a sample can be placed directly on the metal slab waveguide without a metal thin film layer. It is characterized in that the slab type waveguide for optical absorption spectrum measurement made of the slab type transparent substrate thus constructed can be arranged exchangeably. Further, another surface plasmon resonance and optical absorption spectrum measuring apparatus according to the present invention is a measuring unit in which a slab type waveguide can be arranged,
Light source means configured to introduce white light into the slab type waveguide through an optical fiber, and detecting and analyzing light emitted from the slab type waveguide after propagating in the slab type waveguide. A surface plasmon resonance measurement portion including a photodetection means, the measurement unit including a metal thin film layer, and a sample arranged on the metal thin film, and a metal thin film layer not provided, A slab-type waveguide comprising a slab-type transparent substrate having an optical absorption spectrum measurement part configured so that the sample can be directly placed is provided, and the light is a surface plasmon resonance measurement part or an optical absorption spectrum in the slab-type waveguide. It is characterized in that the measuring unit and / or the light source means are configured to be movable so that either one of the measuring units can selectively pass therethrough.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a surface plasmon resonance measuring apparatus according to the present invention will be described below with reference to some embodiments shown in the accompanying drawings.

FIG. 1 is a schematic diagram showing the construction of an embodiment of the surface plasmon resonance measuring apparatus according to the present invention. As shown in the drawing, this measuring device includes a light source means A, a slab type waveguide B, and a light detecting means C. Light source means A
From the light source 1 to the lens 2, the optical chopper 3, the lens 4,
White light is configured to enter the slab-type waveguide through the incident optical fiber 5 and the condenser lens 6. In this embodiment, the optical fiber 5 has a core diameter of 40.
The one with 0 μm was used. As shown in FIG. 2, the slab type waveguide B includes a metal thin film layer 1 on a transparent substrate 10 having a trapezoidal cross section.
1 is formed. In this embodiment, the substrate 10 has a length of 6
A quartz glass plate 5 mm wide and 20 mm wide with a thickness of 0.2
What was polished to mm was used. The light incident surface and the light emitting surface of the substrate 10 were inclined at an angle of 60 ° as shown in FIG. Inclining the light incident surface in this way makes it easier to control the incident angle of light and eliminates the need to separately provide a prism or the like. In addition, the metal thin film layer 11
Is made of gold and is provided on the substrate 10 with titanium 12 interposed therebetween. In this embodiment, the thickness of titanium 12 is 3
The thickness of the metal thin film layer 11 is 50 nm.
The light detecting means C includes an emitting fiber 20 and an emitting lens 2.
1, a spectroscope 22, a photomultiplier tube 23, an amplifier 24 and a computer 25. In the measuring device configured as described above, the white light emitted from the light source 1 passes through the lens 2, the optical chopper 3, and the lens 4 and the optical fiber 5
Will be introduced to. The introduced light passes through the optical fiber 5, is condensed by the condenser lens 6, is then polarized into P-polarized light via the linear polarizer 7, and is incident on the slab type waveguide B at an appropriate angle. . The light entered into the waveguide B repeats total reflection in the waveguide B, and then exits from the waveguide B. In the process of passing through the waveguide B, the surface plasmon resonance phenomenon occurs when the P-polarized light is reflected by the metal thin film layer 11. The light emitted from the waveguide B is introduced into the emitting fiber 20 via the emitting lens 21, and the optical fiber 2
It is sent to the spectroscope 22 by 0, and after being spectroscopically separated by the spectroscope 22, it is inputted to the computer 25 via the photomultiplier tube 21 and the amplifier 22. The computer 25 detects the spectral change of white light based on the input data, and calculates the refractive index of the sample placed on the metal thin film layer 11 based on this spectral change.

FIGS. 3 to 5 show experimental results of measuring the refractive index of water using the measuring device having the above-mentioned structure. In FIG. 3, the width d of the metal thin film layer 11 is 1.0 mm,
The angle of incident light with respect to the incident surface is 7 ° to 16 ° in units of 1 °
FIG. 4 shows the experimental results when the width d of the metal thin film layer 11 was set to 1.5 mm and the angle of the incident light with respect to the incident surface was swung from 4 ° to 17 ° in units of 1 °. FIG. 5 is an experimental result in which the width d of the metal thin film layer 11 is set to 2.0 mm and the angle of incident light with respect to the incident surface is swung from 3 ° to 16 ° in 1 ° units. As shown in FIG. 3 to FIG. 5, in each experiment, the valley of the reflectance due to the surface plasmon resonance phenomenon appears remarkably, and it can be seen that the refractive index of the sample placed on the metal thin film layer 11 can be measured.

In the embodiment described above, an example in which the measuring device is used for measuring surface plasmon resonance is shown.
With the measuring device having the configuration shown in FIG. 1, the slab type waveguide B is simply replaced with the one having the structure shown in FIG.
It is possible to measure the light absorption spectrum. The slab-type waveguide shown in FIG. 6 includes a portion on which a sample 31 is mounted in a strip shape on a substrate 30, and a reference portion 32 on which the sample is not mounted, and a portion on which the sample 31 is mounted and a reference portion 32 on which the sample 31 is not mounted.
The computer 25 can calculate the light absorption spectrum of the sample by comparing Further, if the slab type waveguide is configured as shown in FIG. 7, both the surface plasmon resonance measurement and the optical absorption spectrum measurement can be performed with one slab type waveguide. The slab type waveguide shown in FIG.
0 is provided with a surface plasmon resonance measurement portion 41 having a metal thin film layer formed thereon and an optical absorption spectrum measurement portion 42 having no metal thin film layer, so that the slab waveguide can be moved in the width direction. Alternatively, it is possible to perform both the surface plasmon resonance measurement and the optical absorption spectrum measurement only by configuring the light source means A and the light detection means C to be movable in the width direction of the waveguide.

The size of the slab type waveguide and the size of the metal thin film layer are not limited to those in this embodiment, but preferably, they can be arbitrarily selected from the following size ranges. Slab type waveguide width: 3 mm to 200 mm Thickness: 0.01 mm to 10 mm Metal thin film layer thickness: 20 nm to 80 nm Width: 0.01 mm to 10 mm

[0010]

As described above, the surface plasmon resonance measuring apparatus according to the present invention comprises a slab type waveguide made of a slab type transparent substrate on which a metal thin film is formed, and an optical fiber for the slab type waveguide. A light source means configured to introduce white light through, and a light detection means for detecting and analyzing light emitted from the slab-type waveguide after propagating in the slab-type waveguide, A sample is placed on the metal thin film, white light is made to enter the slab type waveguide using the light source means to propagate the slab type waveguide, and a surface plasmon phenomenon is generated in the metal thin film on which the sample is placed, Since it is configured to detect the spectral change of white light due to the surface plasmon phenomenon from the light emitted from the slab type waveguide using the light detection means, and to measure the refractive index of the sample from the detection result. By simply changing the slab type waveguide to one without a metal thin film layer, it becomes possible to measure the optical absorption spectrum, so there is no need to assemble a device dedicated to surface plasmon measurement as in the past, and the measuring device can be used. This has the effect that it can be used for multiple purposes. Further, the surface plasmon resonance and optical absorption spectrum measuring apparatus according to the present invention is configured to introduce a white light into the slab type waveguide through an optical fiber, and a measuring section to which the slab type waveguide can be detachably attached. The light source means and the light detecting means for detecting and analyzing the light emitted from the slab-type waveguide after propagating in the slab-type waveguide, and the measuring unit having a metal thin film layer, A slab waveguide for surface plasmon resonance measurement consisting of a slab-type transparent substrate configured so that a sample can be placed on a metal thin film, and a sample can be placed directly on the metal slab waveguide without a metal thin film layer. Since the slab waveguide for optical absorption spectrum measurement composed of the configured slab-type transparent substrate is arranged so as to be interchangeable, the surface plasmon resonance is actually used by one device. An effect that it is possible to measure both the optical absorption spectrum. further,
Another surface plasmon resonance and optical absorption spectrum measuring apparatus according to the present invention is a light source configured to introduce a white light into the slab type waveguide through an optical fiber, and a measuring section in which the slab type waveguide can be arranged. Means and, after propagating in the slab type waveguide, comprising a light detection means for detecting and analyzing the light emitted from the slab type waveguide, in the measurement unit,
A surface plasmon resonance measurement part provided with a metal thin film layer so that a sample can be placed on the metal thin film, and an optical absorption device provided without a metal thin film layer so that the sample can be placed directly thereon. Providing a slab type waveguide consisting of a slab type transparent substrate having a spectrum measurement part, and light can selectively pass through either the surface plasmon resonance measurement part or the optical absorption spectrum measurement part in the slab type waveguide. As described above, since the measuring unit and / or the light source means is movable, it becomes possible to measure the surface plasmon resonance and the optical absorption spectrum without the need to replace the substrate, and under the completely same conditions. It is possible to measure the surface plasmon resonance and the optical absorption spectrum of the same sample.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing fairness of an embodiment of a surface plasmon resonance measuring apparatus according to the present invention.

FIG. 2 is a schematic perspective view of a slab type waveguide.

FIG. 3 is a graph showing the results of measuring water with the width d of the metal thin film layer 11 being 1.0 mm.

FIG. 4 is a graph showing the results of measuring water with the width d of the metal thin film layer 11 being 1.5 mm.

FIG. 5 is a graph showing the results of measuring water with the width d of the metal thin film layer 11 being 2.0 mm.

FIG. 6 is a schematic perspective view of a slab type waveguide for measuring an optical absorption spectrum.

FIG. 7 is a schematic perspective view of another embodiment of the slab type waveguide.

[Explanation of symbols]

A light source means 1 light source 2 lens 3 optical chopper 4 lenses 5 Incident optical fiber 6 Condensing lens B Slab type waveguide 10 substrates 11 Metal thin film layer 12 Titanium layer C light detection means 20 Output fiber 21 Output lens 22 Spectrometer 23 Photomultiplier tube 24 amplifier 25 computer 30 substrates 31 samples 32 reference parts 40 substrates 41 Surface plasmon resonance measurement part 42 Optical absorption spectrum measurement part

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 000102739             NTT Advanced Technology             Corporation             2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo (72) Inventor Koji Suzuki             1-1-705 Kokura, Saiwai-ku, Kawasaki-shi, Kanagawa (72) Inventor Kazuyoshi Kurihara             4-1 Idasugiyama-cho, Nakahara-ku, Kawasaki-shi, Kanagawa             305 Claire Maison Oseto (72) Inventor Kozo Takahashi             3-27 Maebaru-cho, Koganei-shi, Tokyo 13-27 (72) Inventor Kenji Kato             5-16 Tsukushino, Abiko City, Chiba Prefecture (72) Inventor Tatsuya Tobita             2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo             Nutty Advance Technology Co., Ltd.             Inside the company (72) Inventor Hisao Tabei             2-1-1, Nishishinjuku, Shinjuku-ku, Tokyo             Nutty Advance Technology Co., Ltd.             Inside the company F-term (reference) 2G059 AA02 EE02 EE05 EE12 GG04                       GG10 JJ01 JJ11 JJ17 JJ19                       JJ24 KK01

Claims (5)

[Claims] 1. A slab type waveguide formed of a slab type transparent substrate on which a metal thin film is formed, and a light source means configured to introduce white light into the slab type waveguide through an optical fiber, A light detecting means for detecting and analyzing light emitted from the slab-type waveguide after propagating in the slab-type waveguide, placing a sample on the metal thin film, and using the light source means to form the slab-type waveguide. White light is made to enter the waveguide and propagated in the slab type waveguide to cause a surface plasmon phenomenon in the metal thin film on which the sample is placed, and the light emitted from the slab type waveguide is used by the light detecting means. A surface plasmon resonance measuring apparatus, characterized in that a spectral change of white light due to a surface plasmon phenomenon is detected, and the refractive index of a sample is measured from the detection result. 2. The surface plasmon resonance measuring device according to claim 1, wherein the light incident surface and the light emitting surface of the slab type waveguide are inclined. 3. The inclination angle of the light incident surface and the light emitting surface is 6
It is 0 degree, The surface plasmon resonance measuring apparatus of Claim 2 characterized by the above-mentioned. 4. A measuring section to which a slab type waveguide can be detachably attached, a light source means configured to introduce white light into the slab type waveguide through an optical fiber, and the inside of the slab type waveguide. And a light detection means for detecting and analyzing the light emitted from the slab-type waveguide after propagating, and the measuring unit is provided with a metal thin film layer, and a sample can be arranged on the metal thin film. A slab-type waveguide for surface plasmon resonance measurement consisting of a transparent slab-type substrate, and a light consisting of a slab-type transparent substrate that does not have a metal thin film layer and can be placed directly on it. An apparatus for measuring surface plasmon resonance and optical absorption spectrum, characterized in that it can be arranged so as to be exchangeable with a slab type waveguide for absorption spectrum measurement. 5. A measuring unit in which a slab type waveguide can be arranged, a light source means configured to introduce white light into the slab type waveguide through an optical fiber, and a light source propagated in the slab type waveguide. After that, a surface plasmon having a light detecting means for detecting and analyzing light emitted from the slab type waveguide, a metal thin film layer being provided in the measuring section, and a sample being arranged on the metal thin film. A slab-type waveguide comprising a transparent slab-type substrate having a resonance measurement part and an optical absorption spectrum measurement part having no metal thin film layer and configured so that a sample can be directly placed thereon is provided. Is movable in the slab type waveguide so that either the surface plasmon resonance measuring portion or the optical absorption spectrum measuring portion can selectively pass therethrough. Surface plasmon resonance and optical absorption spectrum measuring device.