JP2003177090A - Sensor utilizing total reflection attenuation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To also measure the absorbance of a sample in a sensor utilizing total reflection attenuation. <P>SOLUTION: The sensor utilizing total reflection attenuation comprises a dielectric block 10, a light source 14 for generating light beams 13, an optical system 15 for allowing the light beams 13 to enter an interface 10b so that various incident angles can be obtained, and a light detection means 17 for detecting the light beams 13 that are totally reflected from interface 10b for making parallel. The sensor further has a light source 50 for generating light beams 56 for measuring thermal lens effect, an optical system 51 for allowing the light beams 565 to enter the dielectric block 10, a mask 52 for shielding one portion of the light beams 56 through the dielectric block 10, and a light detection section 54 for detecting the light beams 56 through the dielectric block 10 via a mask 52 and an optical system 53, thus measuring thermal lens effect that depends on the absorbance of a sample 11. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor utilizing total reflection attenuation, such as a surface plasmon sensor for quantitatively analyzing a substance in a sample by utilizing the generation of surface plasmon, and more particularly to a total reflection attenuation. The present invention relates to a sensor utilizing attenuation of total reflection for detecting a dark line generated in measurement light by using a light detecting means.

[0002]

2. Description of the Related Art In a metal, free electrons oscillate collectively to generate compression waves called plasma waves. And, the quantized compression wave generated on the metal surface is
It is called surface plasmon.

Conventionally, various surface plasmon sensors have been proposed for quantitatively analyzing a substance in a sample by utilizing the phenomenon that the surface plasmon is excited by a light wave.
Among them, one that is particularly well known is one that uses a system called Kretschmann arrangement (see, for example, JP-A-6-167443).

A surface plasmon sensor using the above system basically emits a light beam and a dielectric block formed in a prism shape, a metal film formed on one surface of the dielectric block and brought into contact with a sample. With respect to the light source to be generated and this light beam with respect to the dielectric block, various angles are set so that total reflection conditions can be obtained at the interface between the dielectric block and the metal film, and total reflection attenuation due to surface plasmon resonance can occur. And an optical system for measuring the intensity of the light beam totally reflected at the interface to detect the state of surface plasmon resonance, that is, the state of attenuated total reflection.

In order to obtain various incident angles as described above, a relatively thin light beam may be incident on the above interface by changing the incident angle, or a component incident on the light beam at various angles. Therefore, a relatively thick light beam may be incident on the interface in a convergent light state or a divergent light state. In the former case, a light beam whose reflection angle changes according to the change of the incident angle of the incident light beam is detected by a small photodetector that moves in synchronization with the change of the above-mentioned reflection angle, or the direction of change of the reflection angle. It can be detected by an area sensor extending along. On the other hand, in the latter case, each light beam reflected at various reflection angles can be detected by an area sensor extending in a direction in which all the light beams can be received.

In the surface plasmon sensor having the above structure, when a light beam is incident on the metal film at a specific incident angle θ _SP which is equal to or greater than the total reflection angle, an evanescent wave having an electric field distribution in the sample in contact with the metal film. Is generated, and surface plasmons are excited at the interface between the metal film and the sample by this evanescent wave. When the wave vector of the evanescent light is equal to the wave number of the surface plasmon and the wave number matching is established, both are in a resonance state and the energy of the light is transferred to the surface plasmon, so that at the interface between the dielectric block and the metal film. The intensity of the reflected light sharply decreases. This decrease in light intensity is generally detected as a dark line by the light detecting means.

The above resonance occurs only when the incident beam is p-polarized. Therefore, it is necessary to set in advance that the light beam is incident as p-polarized light.

When the wave number of the surface plasmon is known from the incident angle θ _{SP at which} this attenuated total reflection (ATR) occurs, the dielectric constant of the sample can be obtained. That is, the wave number of the surface plasmon is K
_{Let SP be} the angular frequency of surface plasmons be ω, c be the speed of light in a vacuum, ε _m and ε _S be the metal, and the permittivity of the sample respectively, and the following relationships are established.

[0009]

[Equation 1] If the permittivity ε _S of the sample is known, the concentration of the specific substance in the sample can be known based on a predetermined calibration curve or the like. Therefore, by finally knowing the incident angle θ _{SP at} which the reflected light intensity decreases, the dielectric constant of the sample can be determined. A property related to the index, that is, the refractive index can be obtained.

As a similar sensor utilizing the attenuated total reflection (ATR), for example, "Spectroscopic Research" Vol. 47, No. 1 (1998), pages 21 to 23 and 26 to 27.
Leakage mode sensors described on the page are also known. This leaky mode sensor is basically formed by, for example, a dielectric block formed in a prism shape, a clad layer formed on one surface of the dielectric block, and formed on the clad layer and brought into contact with a sample. A light guide layer, a light source for generating a light beam, and a total reflection condition for the dielectric block at the interface between the dielectric block and the clad layer, and a light guide for the light guide layer. The optical system that is incident at various angles so that the attenuation of the total reflection due to the excitation of the wave mode may occur, and the intensity of the light beam totally reflected at the interface is measured to determine the excited state of the guided mode, that is, the attenuated total reflection state. And a light detecting means for detecting.

In the leak mode sensor having the above structure,
When a light beam is incident on the cladding layer through the dielectric block at an angle of incidence equal to or more than the total reflection angle, only light with a specific incident angle having a specific wave number is transmitted in the optical waveguide layer after passing through the cladding layer. It propagates in the guided mode. When the guided mode is excited in this manner, most of the incident light is taken into the optical waveguide layer, so that the total reflection attenuation occurs in which the intensity of the light totally reflected at the interface sharply decreases.
Since the wave number of the guided light depends on the refractive index of the sample on the optical waveguide layer, the refractive index of the sample and the related characteristics of the sample are analyzed by knowing the above-mentioned specific incident angle at which attenuation of total reflection occurs. be able to.

[0012]

By the way, from the measurement results obtained from the conventional surface plasmon sensor of the type described above, the leak mode sensor, and other sensors utilizing attenuation of total reflection, the physical properties related to the refractive index of the sample are shown. Since only information can be analyzed, other physical property information could not be obtained.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a sensor utilizing attenuated total reflection capable of measuring not only the refractive index of a sample but also the absorbance of the sample.

[0014]

A first sensor utilizing attenuation of total reflection according to the present invention comprises a dielectric block, a thin film layer formed on one surface of the dielectric block and brought into contact with a sample, and an optical layer. A light source that generates a beam, an optical system that causes the light beam to enter the dielectric block at various angles so that total reflection conditions can be obtained at the interface between the dielectric block and the thin film layer, and total reflection at the interface. In the sensor utilizing attenuated total reflection, which comprises a light detecting means for detecting the intensity of the attenuated light beam and detecting the state of attenuation of total reflection, the light for irradiating the light beam for thermal lens effect measurement toward the sample. Beam irradiation means, mask for blocking a part of the thermal lens effect measuring light beam transmitted through the dielectric block, and the intensity of the thermal lens effect measuring light beam transmitted through the dielectric block is measured through the mask Te, is characterized in that a thermal lens effect detecting means for detecting the state of the thermal lens effect of the sample.

A second sensor utilizing attenuation of total reflection of the present invention is a dielectric block, a metal film formed on one surface of the dielectric block and brought into contact with a sample,
A light source that generates a light beam, an optical system that causes the light beam to enter the dielectric block at various angles so that total reflection conditions can be obtained at the interface between the dielectric block and the metal film, and total light at the interface. Measure the intensity of the reflected light beam,
In a sensor utilizing attenuated total reflection, which comprises a photodetection means for detecting a state of attenuation of total reflection due to surface plasmon resonance, a light beam irradiation means for irradiating a light beam for thermal lens effect measurement toward a sample, A mask that shields a part of the thermal lens effect measurement light beam that has passed through the dielectric block and the intensity of the thermal lens effect measurement light beam that has passed through the dielectric block is measured through the mask, and the sample thermal lens And a thermal lens effect detecting means for detecting the effect state.

Further, a third sensor utilizing attenuation of total reflection of the present invention is a dielectric block, a clad layer formed on one surface of the dielectric block, and a clad layer formed on the clad layer. The optical waveguide layer that is brought into contact with the light source, the light source that generates the light beam, and the light beam that enters the dielectric block at various angles so that total reflection conditions can be obtained at the interface between the dielectric block and the cladding layer. And the optical system to be measured, the intensity of the light beam totally reflected at the interface,
In a sensor utilizing attenuation of total internal reflection, which comprises a photodetection means for detecting the state of attenuation of total internal reflection due to excitation of a guided mode in an optical waveguide layer, a sample is irradiated with a light beam for measuring a thermal lens effect. Light beam irradiation means, a mask for blocking a part of the thermal lens effect measuring light beam transmitted through the dielectric block, and the intensity of the thermal lens effect measuring light beam transmitted through the dielectric block is measured through the mask. And a thermal lens effect detecting means for detecting the state of the thermal lens effect of the sample.

The "thermal lens effect" will be described below. When the light beam passes through the sample, a temperature distribution occurs in the sample along the intensity distribution of the light beam due to photothermal conversion. The intensity distribution of the light beam is strongest along the optical axis and weaker toward the periphery, and the refractive index of the sample is inversely proportional to temperature in most cases, so when the light beam passes through the sample, the refractive index distribution of the sample Conversely, the vicinity of the optical axis becomes low. Optically, this refractive index distribution has the same effect as a concave lens, so this effect is called the thermal lens effect. The magnitude of this effect, ie the power of the concave lens, is proportional to the absorbance of the sample.

The sensor utilizing attenuation of total reflection according to the present invention can measure the absorbance of the sample by utilizing the thermal lens effect in addition to the measurement of the refractive index of the sample. The principle will be described below.

In order to generate the thermal lens effect on the sample by the light beam irradiation means, the sample is irradiated with a constant amount of excitation light (light beam for measuring the thermal lens effect). Then, the intensity of the light beam for thermal lens effect measurement transmitted through this sample is
The detection is performed through a mask having a certain size that shields the approximate center of the light beam. Even if the thermal lens effect occurs in the sample and the optical path of the light beam passing through the sample is deflected, the size of the mask provided between the sample and the thermal lens effect detecting means is constant, so the thermal lens effect detecting means The light quantity of the detected light beam changes depending on the power of the thermal lens, that is, the absorbance of the sample. Therefore, the absorbance of the sample can be measured by detecting the change in the light amount of the light beam by the thermal lens effect detecting means. About this thermal lens effect, "Bunseki" 1998 1
See the January issue, pages 847-853, "Thermal Lens Microscope" for detailed explanation.

[0020]

According to the sensor of the present invention which utilizes the attenuation of total reflection, the light beam irradiation means for measuring the thermal lens effect,
Since the mask and the thermal lens effect detecting means are provided to detect the thermal lens effect depending on the absorbance of the sample, the absorbance of the sample can be measured in addition to the measurement of the refractive index of the sample.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The sensor utilizing attenuation of total internal reflection according to the first embodiment of the present invention is a surface plasmon sensor utilizing surface plasmon resonance, and FIG. 1 shows a side surface shape of the surface plasmon sensor.

This surface plasmon sensor includes, for example, a dielectric block 10 formed by cutting out a part of a roughly square pyramid, and one surface of the dielectric block 10 (upper surface in the figure).
And a metal film 12 made of, for example, gold, silver, copper, aluminum or the like.

The dielectric block 10 is made of, for example, a transparent resin and has a shape in which the periphery of the portion where the metal film 12 is formed is raised, and the raised portion 10a serves as a sample holding portion for storing the liquid sample 11. Function. In this example, the sensing medium 30 is fixed on the metal film 12, and the sensing medium 30 will be described later.

The dielectric block 10 constitutes a disposable measuring chip together with the metal film 12, and is fitted and fixed one by one in a plurality of chip holding holes 31a provided in the turntable 31, for example. After the dielectric block 10 is thus fixed to the turntable 31, the turntable 31 is intermittently rotated by a constant angle, and the liquid sample 11 is dropped onto the dielectric block 10 stopped at a predetermined position. The liquid sample 11 is held in the sample holder 10a. Thereafter, when the turntable 31 is further rotated by a certain angle, the dielectric block 10 is sent to the measurement position shown in FIG. 1 and stopped there.

The surface plasmon sensor of this embodiment is
In addition to the above dielectric block 10, one light beam
A light source 14 (hereinafter referred to as a semiconductor laser that generates 13
Laser light source 14) and the light beam 13 are passed through the dielectric block 10, and the interface between the dielectric block 10 and the metal film 12
An optical system 15 for making various incident angles with respect to 10b, a collimator lens 16 for collimating the light beam 13 totally reflected at the interface 10b, and the collimated light beam. Light detection means 17 for detecting 13 and light detection means
A differential amplifier array 18 connected to 17, a driver 19,
A light source 50 including a semiconductor laser or the like for generating a light beam 56 for measuring the thermal lens effect, an optical system 51 for causing the light beam 56 to enter the dielectric block 10, and a light beam 56 transmitted through the dielectric block 10. A mask 52 for blocking the light, a photodetector 54 for detecting the light beam 56 transmitted through the dielectric block 10 through the mask 52 and the optical system 53, and the dielectric block 10.
Of the optical beam 56 that has not been shielded by the mask 52 among the light beams 56 that have been transmitted through the optical system 53, and the output of the optical detection unit 54 is digitized and input to the signal processing unit 20 A / D converter 55, driver 19 and A / D converter 55
And a display means 21 connected to the signal processing unit 20.

The incident optical system 15 includes a collimator lens 15a for collimating the light beam 13 emitted from the laser light source 14 in a divergent light state, and the collimated light beam 13 for the interface.
It is composed of a condenser lens 15b which converges on 10b.

Since the light beam 13 is condensed so as to converge on the interface 10b, various incident angles .theta.
Will include the component that is incident at. This incident angle θ
Is an angle equal to or greater than the total reflection angle. So the light beam 13
Is totally reflected at the interface 10b, and the reflected light beam 13 has
Components that reflect at various reflection angles will be included. The optical system 15 may be configured to make the light beam 13 incident on the interface 10b in a defocused state. By doing so, the error in detecting the state of the surface plasmon resonance is averaged, and the measurement accuracy is improved.

The light beam 13 is incident on the interface 10b as p-polarized light. In order to do so, the laser light source 14 may be arranged in advance so that the polarization direction thereof becomes a predetermined direction. Alternatively, the polarization direction of the light beam 13 may be controlled by the wave plate.

The light beam 56 for measuring the thermal lens effect is applied to the sample 11
The optical system 51 for making the light incident on the collimator lens 51a for collimating the light beam 56 emitted from the laser light source 50 in a divergent state, and the collimated light beam 56 for the sample 11
It is composed of a condenser lens 51b for converging above.

The sample analysis by the surface plasmon sensor having the above structure will be described below.

First, the measurement of the change in the refractive index of the sample will be described. As shown in FIG. 1, the light beam 13 emitted from the laser light source 14 in a divergent state is converged on the interface 10b between the dielectric block 10 and the metal film 12 by the action of the optical system 15.
Therefore, the light beam 13 includes components that are incident on the interface 10b at various incident angles θ. The incident angle θ is set to an angle equal to or larger than the total reflection angle. There light beam
13 is totally reflected at the interface 10b, and the reflected light beam 13 contains components reflected at various reflection angles.

The light beam 13 which is totally reflected by the interface 10b and then collimated by the collimator lens 16 is detected by the light detecting means 17. The light detection means 17 in this example is
A photodiode array in which a plurality of photodiodes 17a, 17b, 17c ... Are arranged side by side in one row, and the photodiodes are arranged in the plane of FIG. 4 with respect to the traveling direction of the collimated light beam 13. They are arranged so that the juxtaposed directions are substantially right angles. Therefore, each component of the light beam 13 totally reflected at various reflection angles at the interface 10b is
Different photodiodes 17a, 17b, 17c ...
Will receive light.

FIG. 2 is a block diagram showing the electrical construction of this surface plasmon sensor. As shown in the figure, the driver 19 includes the differential amplifiers 18 a, 18 a of the differential amplifier array 18.
The sample-hold circuits 22a, 22b, 22c, ... for sampling and holding the outputs of b, 18c .., the multiplexer 23 to which the outputs of these sample-hold circuits 22a, 22b, 22c. A / D converter 24 that digitizes and inputs to signal processing unit 20, multiplexer 23 and sample hold circuits 22a, 22b, 22
.. and c, and a controller 26 that controls the operation of the drive circuit 25 based on an instruction from the signal processing unit 20.

The photodiodes 17a, 17b, 17c ...
Each output of ... is the difference amplifier 18 of the difference amplifier array 18.
It is input to a, 18b, 18c .... At this time, the outputs of two photodiodes adjacent to each other are input to a common differential amplifier. Therefore, each differential amplifier 18a, 18b,
The output of 18c ... is a plurality of photodiodes 17a, 17
It can be considered that the photodetection signals output by b, 17c ... Are differentiated with respect to their parallel arrangement direction.

The outputs of the differential amplifiers 18a, 18b, 18c, ... Are sample and hold circuits 22a, 22b, 22c ,.
Are sample-held at a predetermined timing by the ... And input to the multiplexer 23. The multiplexer 23 includes the sample-and-hold differential amplifiers 18a, 18b, 18c ...
The outputs of ... Are input to the A / D converter 24 in a predetermined order. The A / D converter 24 digitizes these outputs and inputs them to the signal processing unit 20.

FIG. 3 shows the light beam 13 totally reflected at the interface 10b.
Intensity of each incident angle θ and differential amplifiers 18a, 18b, 18c
It describes the relationship with the output of. Here, it is assumed that the relationship between the incident angle θ of the light beam 13 on the interface 10b and the light intensity I is as shown in the graph of FIG.

Light incident on the interface 10b at a specific incident angle θ _SP excites surface plasmons at the interface between the metal film 12 and the liquid sample 11, so that the reflected light intensity I
Sharply drops. In other words, θ _SP is the total reflection elimination angle,
The reflected light intensity I takes a minimum value at this angle θ _SP .
This decrease in the reflected light intensity I is observed as a dark line in the reflected light, as indicated by D in FIG.

Further, FIG. 3B shows the photodiode 17
a, 17b, 17c ... are shown in a line, and as described above, these photodiodes 17a, 17b, 17c are shown.
The position in the parallel direction of ...... uniquely corresponds to the incident angle θ.

Then, the photodiodes 17a, 17b, 17c
……, the parallel installation position, that is, the incident angle θ and the differential amplifier
The relationship between the outputs 18 ', 18b, 18c ... And the output I' (differential value of the reflected light intensity I) is as shown in FIG.

The signal processing unit 20 is based on the value of the differential value I'input from the A / D converter 24, and the differential amplifiers 18a, 18a are provided.
From b, 18c, etc., select the one (the differential amplifier 18d in the example of FIG. 3) that gives the output that is closest to the differential value I ′ = 0 corresponding to the total reflection elimination angle θ _SP . , The differential value I ′ output therefrom is subjected to a predetermined correction process, and then the value is displayed on the display means 21. In some cases, there is a differential amplifier that outputs a differential value I ′ = 0, and in that case, that differential amplifier is naturally selected.

Thereafter, every time a predetermined time elapses, the differential value I'output from the selected differential amplifier 18d is displayed on the display means 21 after undergoing a predetermined correction process. This differential value I ′ changes when the permittivity of the substance in contact with the metal film 12 of the measuring chip, that is, the refractive index changes, and the curve shown in FIG. Up and down accordingly. Therefore, by continuously measuring the differential value I ′ with the passage of time, it is possible to investigate the change in the refractive index of the substance in contact with the metal film 12, that is, the change in the characteristic.

In particular, in the present embodiment, the liquid sample is formed on the metal film 12.
The sensing medium 30 that binds to the specific substance in 11 is fixed, and the refractive index of the sensing medium 30 changes according to the binding state thereof. Therefore, by continuously measuring the differential value I ′, this binding You can check how the state changes. That is, in this case, both the liquid sample 11 and the sensing medium 30 are samples to be analyzed. Examples of such a combination of the specific substance and the sensing medium 30 include an antigen and an antibody.

As is apparent from the above description, in the present embodiment, the plurality of photodiodes 17a as the light detecting means 17,
Since a photodiode array in which 17b, 17c, ... Are arranged side by side in a row is used, depending on the liquid sample 11, FIG.
Even if the curve shown in (1) moves to the left and right and changes significantly to some extent, dark line detection is possible. That is, the use of such an array-shaped light detecting means 17 can secure a large dynamic range of measurement.

A plurality of differential amplifiers 18a, 18b, 18c
One differential amplifier is provided instead of using the differential amplifier array 18 consisting of ... And photodiodes 17a, 17b, 17
It is also possible to switch each output of c ... With a multiplexer so that two adjacent outputs of them are sequentially input to this one differential amplifier.

In order to investigate the change in the binding state between the specific substance in the liquid sample 11 and the sensing medium 30 with the passage of time, the differential value I '
In addition to displaying, the first measured differential value I '(0)
And the differential value I '(t) measured after the lapse of a predetermined time Δ
I ′ may be obtained and displayed.

Next, the measurement of the absorbance of the sample will be described. A light beam 56 is made incident from a light source 50 via an optical system 51 so as to spread from above the sample to below the dielectric block 10. When the sample 11 is irradiated with the light beam 56, a thermal lens effect is generated in the sample 11 according to the absorbance of the sample 11, so that the optical path of the light beam 56 is deflected outward about the optical axis. Here, since the size of the mask 52 provided between the sample 11 and the light detection unit 54 is constant, the greater the thermal lens effect in the sample 11, the more the optical system 53 is shielded by the mask 52.
The light amount of the light beam 56 detected by the light detection unit 54 via the light source increases. The magnitude of the thermal lens effect of sample 11 is
Since it depends on the absorbance of
The absorbance of the sample 11 can be measured by detecting the light amount of. The output of the photodetector 54 is digitized by the A / D converter 55 and input to the signal processor 20.

Next, a second embodiment of the present invention will be described with reference to FIG. In addition, in FIG.
Elements that are the same as the elements inside are given the same numbers, and descriptions thereof are omitted unless otherwise necessary.

The sensor utilizing attenuation of total reflection according to the present embodiment is obtained by changing the surface plasmon sensor described in the first embodiment into a leaky mode sensor, and in this example as well, a dielectric that is made into a measurement chip. It is configured to use the block 10. A clad layer 40 is formed on one surface (upper surface in the figure) of the dielectric block 10, and an optical waveguide layer 41 is further formed thereon.

The dielectric block 10 is made of, for example, synthetic resin or B.
It is formed using an optical glass such as K7. On the other hand, the clad layer 40 is formed in a thin film shape using a dielectric having a lower refractive index than the dielectric block 10 or a metal such as gold. The optical waveguide layer 41 is a dielectric material having a higher refractive index than the cladding layer 40,
For example, PMMA is also used to form a thin film. The clad layer 40 has a film thickness of, for example, 36.5 nm when formed from a gold thin film, and the optical waveguide layer 41 has a film thickness of, for example, PMMA.
When formed from, the thickness is about 700 nm.

In the leak mode sensor having the above structure,
Dielectric block the light beam 13 emitted from the laser light source 14.
When the light beam 13 is incident on the clad layer 40 through 10 at an incident angle equal to or larger than the total reflection angle, the light beam 13 is totally reflected at the interface 10b between the dielectric block 10 and the clad layer 40.
Light having a specific wave number that has passed through the optical waveguide layer 41 and is incident on the optical waveguide layer 41 at a specific incident angle propagates through the optical waveguide layer 41 in the guided mode. When the guided mode is excited in this way, most of the incident light is taken into the optical waveguide layer 41, so that the total reflection attenuation occurs in which the intensity of the light totally reflected at the interface 10b sharply decreases.

Since the wave number of the guided light in the optical waveguide layer 41 depends on the refractive index of the liquid sample 11 on the optical waveguide layer 41, by knowing the specific incident angle at which attenuation of total reflection occurs,
The refractive index of the liquid sample 11 and the characteristics of the liquid sample 11 related thereto can be analyzed. Then, based on the reflected light intensity I in the vicinity of the specific incident angle and the differential value I ′ output from each differential amplifier of the differential amplifier array 18, the liquid sample 11
The characteristics of can also be analyzed.

Also in the present embodiment, the same effect as in the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a side view of a surface plasmon sensor according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the surface plasmon sensor.

FIG. 3 is a schematic diagram showing the relationship between the light beam incident angle and the detected light intensity in the surface plasmon sensor, and the relationship between the light beam incident angle and the differential value of the light intensity detection signal.

FIG. 4 is a side view of a leaky mode sensor according to a second embodiment of the present invention.

[Explanation of symbols]

10 Dielectric block 10a Dielectric block sample holder 10b Interface between dielectric block and metal film 11 samples 12 Metal film 13 light beam 14 Semiconductor laser, etc. 15 Optical system 16 collimator lens 17 Light detection means (photodiode array) 17a, 17b, 17c ... Photodiodes 18 Differential amplifier array 18a, 18b, 18c ... Differential amplifier 19 driver 20 Signal processor 21 Display means 22a, 22b, 22c ... Sample hold circuit 23 Multiplexer 24 A / D converter 25 Drive circuit 26 Controller 30 Sensing medium 31 turntable 40 clad layer 41 Optical waveguide layer 50 Semiconductor laser, etc. 51 Optical system 52 Optical system 53 mask 54 Photodetector 55 A / D converter 56 Light beam (for measuring thermal lens effect)

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2G040 AA03 AB07 CA12 CA23                 2G057 AA02 AB04 AB07 AC01 BA01                       BB01 BB06 HA04                 2G059 AA02 BB04 DD12 EE01 EE02                       GG01 GG04 JJ11 JJ30 KK04                       MM09

Claims (3)

[Claims] 1. A dielectric block, a thin film layer formed on one surface of the dielectric block and brought into contact with a sample, a light source for generating a light beam, and the light beam with respect to the dielectric block. An optical system that makes incidence at various angles so that total reflection conditions are obtained at the interface between the dielectric block and the thin film layer, and the intensity of the light beam totally reflected at the interface is measured to determine the state of attenuation of total reflection. In a sensor utilizing attenuated total reflection, which comprises a light detection means for detecting the light beam, a light beam irradiation means for irradiating a light beam for thermal lens effect measurement toward the sample, and the heat transmitted through the dielectric block. A mask that shields a part of the lens effect measuring light beam, and the intensity of the thermal lens effect measuring light beam that has passed through the dielectric block is measured through the mask, and the thermal radiation of the sample is measured. Sensor utilizing attenuated total reflection, characterized in that a thermal lens effect detecting means for detecting the state of FIG effect. 2. A dielectric block, a metal film formed on one surface of the dielectric block and brought into contact with a sample, a light source for generating a light beam, and a light beam for the dielectric block. An optical system that makes incidence at various angles so that total reflection conditions are obtained at the interface between the dielectric block and the metal film, and the intensity of the light beam totally reflected at the interface is measured, and the result is associated with surface plasmon resonance. A sensor utilizing attenuated total reflection, comprising: a light detection means for detecting a state of attenuation of total reflection; a light beam irradiation means for irradiating a thermal lens effect measuring light beam toward the sample; and the dielectric block. A mask for shielding a part of the thermal lens effect measuring light beam that has passed through, and the intensity of the thermal lens effect measuring light beam that has passed through the dielectric block via the mask. Constant to the sensor that utilizes attenuated total reflection, characterized in that a thermal lens effect detecting means for detecting the state of the thermal lens effect of the sample. 3. A dielectric block, a clad layer formed on one surface of the dielectric block, an optical waveguide layer formed on the clad layer and brought into contact with a sample, and a light source for generating a light beam. An optical system that causes the light beam to enter the dielectric block at various angles so that total reflection conditions can be obtained at the interface between the dielectric block and the cladding layer; and total reflection at the interface A sensor utilizing attenuated total internal reflection, which comprises: a light detecting unit that measures the intensity of a light beam and detects a state of attenuated total internal reflection caused by excitation of a guided mode in the optical waveguide layer; A light beam irradiating means for irradiating the thermal lens effect measuring light beam toward the mask, a mask for shielding a part of the thermal lens effect measuring light beam transmitted through the dielectric block, and a mask for transmitting the dielectric block. Attenuation of total reflection is characterized by further comprising: thermal lens effect detecting means for measuring the intensity of the thermal lens effect measuring light beam through the mask to detect the state of the thermal lens effect of the sample. The sensor used.