JP5343479B2 - Two-photon absorbing organic materials and their applications - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixture which is easy to control: a resonance frequency of a surface plasmon utilizing interaction of a photoelectric field in the range from a visible wavelength to a near-infrared wavelength and the surface plasmon; and the distance between a metal and a material, and allows a plasmon enhancing effect to be effectively utilized and is excellent in uniformity of three-dimensional characteristics and environmental stability, and to provide a plasmonics device utilizing the mixture. <P>SOLUTION: There is provided (1) the mixture including: metal fine particles whose surfaces are coated with a polymer material whose surface is further coated with an inorganic oxide; and a two-photon absorption organic material. There is provided (2) the mixture described in (1), wherein the polymer material is water-soluble. Provided is (3) the mixture described in (1) or (2), wherein the polymer material is an electrolyte. Provided is (4) the mixture described in any of (1) to (3), wherein the metal fine particle is gold. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a sensitization technique for a two-photon absorption organic material using a surface plasmon enhancement field generated in metal fine particles. Further, the present invention is applied to uses such as a three-dimensional optical recording medium, an optical modeling apparatus, a light limiting apparatus, and a two-photon excitation fluorescence detection apparatus.

First, the multiphoton absorption organic material will be described.
Conventionally, various proposals have been made on technologies utilizing multiphoton transitions. This multiphoton transition is a transition in which atoms or molecules simultaneously absorb or emit two or more photons, and is a typical transition. In addition, there are multiphoton absorption that simultaneously absorbs a large number of photons, multiphoton emission that simultaneously emits a large number of photons, a Raman effect that absorbs one photon and simultaneously emits another one. Generally, it is a transition caused by higher-order perturbations that occur even when there is no energy level that absorbs or emits one photon at that frequency, and is observed at a high photon density such as laser light. And the selection rules are different.
In particular, the two-photon absorption phenomenon involving two photons is related to the third-order nonlinear optical effect, and various studies have been conducted in the past.

On the other hand, organic materials are generally known to absorb one photon equal to its transition energy (excitation energy) to produce a transition state (excited state) allowed by the one-photon absorption selection rule. Yes.
However, when light with a high photon density, such as laser light, is irradiated, two photons equal to half the energy of the excitation energy are simultaneously absorbed and a transition may occur.
The phenomenon of simultaneously absorbing these two photons is
(1) Since absorption occurs in proportion to the square of the incident light intensity, a transition occurs only near the focal point where the photon density is high.
(2) Since it can be excited by a photon having half the energy of absorbing one photon, the incident light reaches the deep part of the material without attenuation of light by one-photon absorption.
In recent years, various application technologies that take advantage of the above characteristics have been studied along with the technological progress of high-power lasers. ing.

For example, using the three-dimensional high resolution as described above, a recording layer is formed on a plane, and these are stacked in an optical recording medium that performs recording and reproduction by light incident in a direction perpendicular to the plane. Studies on three-dimensional optical recording media have been conducted (for example, see Patent Documents 1 to 6). These are considered to be capable of super-resolution recording because data can be recorded by causing spectral change, refractive index change or polarization change due to two-photon absorption only in the vicinity of the focal point where the photon density is high.
In addition, technical proposals have also been made regarding application to stereolithography applications (see, for example, Patent Documents 7 to 11). Furthermore, the use of such a two-photon absorption phenomenon such as a sensor and light limitation, and the use as a confocal microscope are also regarded as extremely important (see, for example, Patent Documents 12 to 15).

Next, the surface plasmon enhancement technique will be described.
Plasmons are free electrons that oscillate collectively in metals. On the metal surface, it is known that when light is irradiated, the light is absorbed, and the light is converted into surface plasmons and an electric field that is remarkably enhanced locally is generated. This is thought to be because light energy is converted into surface plasmons, so that light energy is stored in a very limited space called the metal surface, and the region where the metal surface interacts with light is locally focused. Yes.
In metal fine particles (herein, “metal fine particles” means particles in which metal atoms aggregate together and grow to a nanometer size), since plasmons are localized on the surface, localization (surface ) Called plasmon. This plasmon has a feature that it is very excellent in coupling efficiency with a photoelectric field in the visible to near-infrared wavelength region.
Such interaction between light and surface plasmon is, for example, surface enhanced Raman scattering (SERS) in which the Raman signal on the metal surface is enhanced by 10 ³ to 10 ⁸ times, and the emission intensity of the fluorescent material is nearly 10 ² times. On the other hand, it is also known as a phenomenon in which light emission is quenched when a fluorescent material is brought close to a metal.

In recent years, in the photochemical technology field, applied technology using such a phenomenon has been attracting attention.
For example, a technical proposal as an example in which a plasmon enhancement technique is applied in a one-photon transition process has been made (see, for example, Patent Document 16). In this method, surface plasmons generated on a metal surface are used to evaluate optical properties of a trace amount of material. In this technique, since the enhancement field due to surface plasmon is generally limited to a region of about 100 nm or less from the metal surface, the measurement sample is fixed as an extremely thin film on a metal thin film formed on a high refractive index medium. Therefore, it is an example of an applied technology that utilizes a two-dimensionally expanded enhancement field.
On the other hand, in Patent Document 17, which is an example using such an enhancement field three-dimensionally, a technique is disclosed in which metal particles are arranged in a porous three-dimensional matrix to enhance the fluorescence intensity of the fluorescent material. Yes.

JP-T-2001-524245 Special table 2000-512061 gazette Special table 2001-522119 gazette Special table 2001-508221 gazette JP-A-6-28672 JP-A-6-118306 JP 2005-134873 A JP-A-8-320422 JP 2004-277416 A JP-A-11-167036 JP 2005-257741 A JP 2005-123513 A JP 2001-210857 A JP 2005-132663 A JP 2005-165212 A JP 2004-156911 A JP 2005-524084 A

In creating a plasmonics device that three-dimensionally utilizes the interaction between surface plasmons and light, it is necessary to solve the following problems (1) to (7).
(1) The material to be excited can be used three-dimensionally.
The material to be excited can be used three-dimensionally without incident light attenuation due to, for example, scattering of the irradiated light by the material or absorption outside the reaction site (incident light can reach deep inside the material) N) Photo-responsive material.
Similarly, the plasmon-generating metal must also have a three-dimensionally usable structure that is not susceptible to light scattering.
(2) Photoelectric field in the visible to near-infrared wavelength region and plasmon should be coupled efficiently.
The condensed beam diameter of the irradiation light is proportional to λ / NA where the numerical aperture of the objective lens is NA and the wavelength λ. Therefore, in general, the smaller the λ is, the narrower the condensed beam diameter is, thereby realizing higher density. However, since many photoresponsive materials have absorption characteristics in the ultraviolet region, it is desirable that the interaction with plasmons can be utilized from the visible region to the near infrared region, which has a slightly longer wavelength than the ultraviolet region. Therefore, it is desirable that the metal generating plasmon has a plasmon resonance frequency in the visible to near infrared region.

(3) It is easy to control the plasmon resonance frequency (absorption wavelength).
If the plasmon resonance frequency is not variable to some extent, there is a limit to the usable light source of irradiation light, which causes a reduction in the degree of freedom in device design. From such a viewpoint, it is important that the plasmon resonance frequency is easily controlled.
(4) Energy transfer between metal and material is suppressed.
I mentioned earlier that quenching of light emission occurs when a fluorescent material is brought close to a metal. Generally, when trying to photoexcite a material using plasmons, the excitation energy flows toward the metal and is enhanced by plasmons. The effect may not be obtained. Therefore, some contrivance is required to suppress such energy transfer between the metal and the material.
(5) The distance between the metal and the material can be easily controlled.
On the other hand, it is also known that the influence of the enhancement field due to plasmon decreases in inverse proportion to the cube of the distance from the metal surface. Therefore, in order to obtain an effective enhancement effect due to plasmon, between metal and material Establishing appropriate distance control technology is also essential.
(6) Excellent stability against irradiation light and surrounding environment.
Further, when considering the device as a whole, it is also important to have high stability against the thermal deformation of materials and metals caused by irradiation light and the influence of the surrounding environment.
(7) The characteristics are three-dimensionally uniform.
Furthermore, since variation in characteristics greatly affects the reliability of the device, ensuring uniformity is a particularly important issue.

In response to such a request, for example, in Patent Document 16, it is necessary to fix a sample on a metal thin film in order to obtain an enhancement effect using surface plasmons. Since it depends on the arrangement, it is difficult to apply it to a three-dimensional plasmonic device.
Further, for example, in Patent Document 17, the metal fine particles are arranged in a porous three-dimensional matrix, but there remains a problem that it is difficult to obtain the enhancement effect uniformly in each place.
In addition, the inventors of the present invention have developed and applied for a technique related to a mixture composed of a two-photon absorbing material and metal fine particles, particularly for the purpose of solving the problem (4) (see Japanese Patent Application Laid-Open No. 2008-122439). However, this time, when the present inventors use metal fine particles coated with an inorganic oxide via a polymer material as in the present invention, the stability of the inorganic oxide film is dramatically improved as compared with the prior art. In addition, the inventors have found that the enhancement effect by plasmons can be more effectively brought out, and have reached the present invention.
That is, the object of the present invention is to use the interaction between the surface plasmon and the photoelectric field in the visible to near-infrared wavelength region, to easily control the resonance frequency of the surface plasmon, the distance between the metal and the material, and to enhance the plasmon. An object of the present invention is to provide a mixture that can be effectively used and has excellent three-dimensional property uniformity and environmental stability, and a plasmonics device using the mixture.

The above problems are solved by the following inventions 1) to 16) (hereinafter referred to as the present inventions 1 to 16).
1) A mixture comprising fine metal particles whose surface is coated with a polymer material, and whose surface is further coated with an inorganic oxide, and a two-photon absorption organic material.
2) The mixture according to 1), wherein the polymer material is water-soluble.
3) The mixture according to 1) or 2), wherein the polymer material is an electrolyte.
4) The mixture according to any one of 1) to 3), wherein the metal fine particles are gold.
5) The mixture according to any one of 1) to 4), wherein the shape of the metal fine particles is a nanometer-sized rod shape.
6) The mixture according to any one of 1) to 5), wherein the number of metal fine particles coated with the inorganic oxide is one.
7) The mixture according to any one of 1) to 5), wherein metal fine particles contained in one particle of the inorganic oxide are oriented in the same direction.
8) An optical recording material comprising the mixture according to any one of 1) to 7).
9) An optical modeling material comprising the mixture according to any one of 1) to 7).
10) A light-limiting material comprising the mixture according to any one of 1) to 7).
11) A two-photon excited fluorescent material comprising the mixture according to any one of 1) to 7).
12) In a three-dimensional optical recording medium in which a recording layer is formed on a plane and recording / reproduction can be performed on the plane and in a direction perpendicular to the plane, the mixture according to any one of 1) to 7) is optically recorded. A three-dimensional optical recording medium, characterized in that it is included as at least a part of a recording layer on which is performed.
13) In the optical modeling apparatus which performs optical modeling by irradiating the laser beam condensed on the photocurable resin, the mixture according to any one of 1) to 7) is included as at least a part of the photocurable resin. A stereolithography apparatus characterized by that.
14) In the light limiting device provided with the element that limits the light transmission light intensity of the signal light by the control light, the mixture according to any one of 1) to 7) is included as at least a part of the element. A light limiting device characterized by the above.
15) A light limiting device including an element that limits the path of signal light with control light, wherein the mixture according to any one of 1) to 7) is included as at least a part of the element. Characteristic light limiting device.
16) A sample according to any one of 1) to 7) is selectively supported on an analyte in a sample, and the analyte is irradiated with light, so that two of the two-photon absorbing materials contained in the mixture are irradiated. A two-photon excitation fluorescence detection apparatus characterized by having a function of detecting an analyte by expressing and detecting photon fluorescence light.

Hereinafter, the present invention will be described in detail.
<About the present invention 1>
Many inorganic materials have been found so far in the two-photon absorption material. In inorganic materials, the so-called “molecule” is used to optimize the desired two-photon absorption characteristics and various physical properties necessary for device manufacturing. Since “design” is difficult, it is disadvantageous for practical use.
On the other hand, organic materials with excellent processability and mass productivity and relatively easy molecular design compared to inorganic materials are microscopic unlike dielectric materials and semiconductor materials that exhibit two-photon absorption characteristics in a macroscopic charge state. The two-photon absorption property is exhibited even in a simple molecular state, and the property as an aggregate has a macroscopic two-photon absorption property. A large two-photon absorption characteristic can be expected, which is preferable as a two-photon absorption material constituting the present invention.

For the two-photon absorption material constituting the mixture of the present invention, π-conjugated organic molecules are suitable. In general, the main cause of the nonlinearity of the molecule is that the charge transfer in the molecule is dominant, which means that a conjugated molecule having a long effective conjugate length causes a large nonlinear effect, that is, a two-photon transition. It means that it is easy to do.
In the molecular structure, π-conjugated molecules correspond to this, specifically, benzene derivatives, styryl derivatives, stilbene derivatives, cyclic structure compounds represented by porphyrins, conjugated ketone derivatives, and conjugated polymers such as polyacetylene and polydiacetylene, Examples thereof include metal chelate compounds represented by azo metal chelates, and fluorescent dyes represented by rhodamine and coumarin.

In addition, as described above, the present inventors have applied for a technique relating to a mixture of a two-photon absorption material and metal fine particles. In the present invention, the metal fine particles are coated with an inorganic oxide via a polymer material. As a result, the stability of the inorganic oxide film is dramatically improved, and the enhancement effect by plasmons can be used more effectively.
Details regarding this reason are unclear, but perhaps when the metal fine particles are coated with an inorganic oxide without using a polymer material, the coverage of the inorganic oxide film on the metal fine particles is relatively lower than that of the present invention. Or because the coated inorganic oxide is easily peeled off, the energy transfer between the metal fine particles and the two-photon absorption material is not sufficiently suppressed, and therefore, it is considered that the enhancement effect by plasmons could not be maximized. .
The polymer material to be used is appropriately selected from water-soluble and water-insoluble materials depending on the form of metal fine particles to be coated and the production method, but it is important that at least the two-photon absorption characteristics of the two-photon absorption material are not impaired. It is.

On the other hand, examples of metals that cause plasmon resonance include gold, silver, platinum, copper, aluminum, palladium, and other noble metals. After coating these fine metal particles with the polymer material, excitation between the metal and the material is further performed. For the purpose of suppressing energy transfer and improving light resistance and heat resistance, it is coated with an insulating inorganic oxide.
As described above, it is known that the plasmon enhancement field decreases according to the distance from the surface of the metal fine particle. However, if the distance between the metal and the material is too close in order to obtain an efficient plasmon enhancement effect, energy transfer occurs again due to the quantum effect even if the inorganic oxide film as described above is provided. It is necessary to use an inorganic oxide material that enables distance control in the metric order.

Such materials include silane coupling agents represented by alkoxysilane, chlorosilane, etc., or titanate coupling agents (titanium coupling agents), zirconate coupling agents (zirconium coupling agents), aluminate cups. A ring agent (aluminum coupling agent) can be illustrated.
These materials have the advantage that the coverage on the metal surface can be changed simply by changing the molecular weight of the hydrophobic group usually composed of long-chain alkyls, etc., or simply changing the concentration in the reaction solution. have.
The coupling agent is generally represented by XR ¹ _n (R ² ) _4-n , where X is a metal atom exemplified by Si, Ti, Zr and Al, and R ¹ is an optionally substituted hydrocarbon group. , R ² represents a hydrolyzable group, and n represents an integer of 1 to 3. R ¹ is preferably an alkyl group or an alkenyl group, and examples of R ² include a free group having an oxygen atom or nitrogen atom directly bonded to X, a halogen atom, and an amino group.

Specific examples of the silane coupling agent include tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and vinyl. Alkoxy silanes such as trimethoxysilane, vinyltriethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, p-styryltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, trimethylchlorosilane, dimethyldichlorosilane , Allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroe Le trichlorosilane, beta-chloroethyl trichlorosilane, chloromethyl dimethyl chlorosilane, chlorosilanes, and the like typified by vinyl trichlorosilane and the like.
Of these, tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane from the viewpoint of easily realizing a stable inorganic oxide film It is more preferable to use any of the above.

  Titanium coupling agents include tetrapropyl titanate, tetraisopropyl titanate, tetrabutyl titanate, butyl titanate, tetra (2-ethylhexyl) titanate, tetramethyl titanate, tetraethyl titanate, acetylacetonate titanate, titanium tetraacetylacetonate, titanium Examples include ethyl acetoacetate, acetyl tripropyl titanate, titanium octanediolate, lactate titanate, isostearyl titanate, triethanolamine titanate, polyhydroxy titanium stearate, ethyl acetoacetate ester titanate and the like. Among these, from the viewpoint of stabilizing the adhesion, it is preferable to use either tetraisopropyl titanate or tetrabutyl titanate.

  Zirconium coupling agents include tetrapropyl zirconate, tetraisopropyl zirconate, tetrabutyl zirconate, tetra (triethanolamine) zirconate, zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium bisacetylacetonate, zirconium Examples thereof include monoethyl acetoacetate, zirconium acetylacetonate, bisethylacetoacetate, zirconium acetate, zirconium monostearate, n-propyl zirconate, n-butyl zirconate and the like. Among these, from the viewpoint of stabilizing the adhesion, it is preferable to use either n-propyl zirconate or n-butyl zirconate.

  Examples of the aluminum coupling agent include aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum-sec-butyrate, aluminum ethylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethyl acetoacetate), alkyl Acetoacetate aluminum diisopropylate, acetoalkoxyaluminum diisopropylate, aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetonate), aluminum monoisopropoxymonooroxyethylacetoacetate, cyclic aluminum oxide isopropylate , Cyclic aluminum oxide octylate, cyclic aluminum Oxide stearate. Among these, it is preferable to use either alkyl acetoacetate aluminum diisopropylate or acetoalkoxyaluminum diisopropylate.

<About Inventions 2 and 3>
Currently, various reports have been made on the method for producing metal fine particles, including the gas phase method, the liquid phase method and the solid phase method, but the production method using a reducing reagent in an aqueous solvent is particularly reproducible. Since the process is easy (easy to handle), it is widely recognized as a standard synthesis method.
In the case where the metal fine particles in the aqueous solvent obtained by such a simple method are coated with a polymer material, the water-soluble polymer material can be directly coated without an extra step such as solvent replacement. It is preferable because it is possible.
Here, examples of the water-soluble polymer material include the following polymer electrolytes (or polymer electrolytes: polymer materials obtained by kneading an electrolyte in an insulating polymer) and polymer non-electrolytes.

i) Polymer electrolyte Specific examples of water-soluble polyanions include water-soluble polyaniline having acidic groups such as polyvinyl sulfonic acid, polystyrene sulfonic acid, poly-2-acrylamido-2-methylpropane sulfonic acid (PAMPS), and polyvinyl phosphoric acid. Examples include polymer materials.
Examples of the water-soluble polycation include at least one selected from the group consisting of primary to quaternary amino groups having an average molecular weight of 1000 or more, preferably 10,000 to 100,000, and salts thereof. Specific examples include polycation compounds containing seeds, specifically, polyalkylene polyamines such as polyethyleneimine and polypropyleneimine, modified polyethyleneimine, polyallylamine, polyvinylamine, and polyetheramine.
ii) Polymer non-electrolytic materials Non-electrolyte water-soluble polymer materials include polyvinyl polymer materials such as polyvinyl alcohol, polyvinyl methyl ether, polyvinyl pyrrolidone and carboxyvinyl polymer, and polyoxyethylene polymer materials such as polyethylene glycol. And copolymeric polymer materials such as polyoxyethylene polyoxypropylene copolymer.

Methods for coating with the polymer material include spin coating, electrolytic polymerization, vacuum deposition, and CVD, but these methods are difficult to control molecular orientation, and only a very simple film is formed. Can not do it.
On the other hand, the LB method can form a thin film of a monomolecular layer, and by using different conductive polymer solutions, it is also possible to form a thin film having a multilayer heterostructure controlled at the molecular level. There are various problems in the process, restrictions on usable materials, and further, the film adsorption principle is based on intermolecular force (Van der Waals force), resulting in a problem that the film strength is weak.
On the other hand, the alternate adsorption method, which can control the material at the molecular level and can form both single-layer and multilayer heterostructures, has many types of substances that can be handled and does not require the use of a large apparatus. Therefore, it is excellent in practicality and is preferable as a production method of the present invention.

Specifically, by simply immersing metal particles in the polycation and polyanion polymer electrolyte solution alternately, the electrolyte polymer can be spontaneously adsorbed on the surface, and can be self-assembled. can do.
In addition, since the film adsorption principle is based on electrostatic force (Coulomb force), the problem of film strength is also improved, which is an advantageous manufacturing method for “distance control on the order of nanometers”.
However, polyelectrolytes generally have the disadvantage of poor environmental stability. Therefore, finally, it is preferable that the outermost layer is coated with a polymer non-electrolyte. In this case, the adsorption principle is not electrostatic, and physical adsorption is caused by entanglement of both polymer chains.
Moreover, when forming such a multilayer polymer coating structure, polyvinylpyrrolidone is particularly well soluble in water, unlike many synthetic polymer compounds, among other polymer non-electrolytes. This is preferable because it has excellent practical properties such as solubility, compatibility with resin, film-forming property, and adhesiveness.

<About the present invention 4>
In the visible region, gold or silver is particularly known as a metal that can obtain strong resonance due to localized plasmons, but the controllability of the wavelength used (as described later, because gold can be formed into nanorods), Gold is particularly preferable because of excellent environmental stability.

<About Invention 5>
It is known that fine particles having shape anisotropy can control the absorption wavelength (resonance wavelength) by adjusting the aspect ratio of the particles.
Among the fine particles having shape anisotropy, rod-shaped fine particles (hereinafter referred to as nanorods) having a particle size of nanometer order (specifically, 1 to 100 nm, more preferably 1 to 50 nm), i) Fine particles with an aspect ratio of 20 nm or less in diameter can be obtained with good reproducibility, ii) Efficient sensitivity enhancement with low scattering loss is possible, iii) Local surface plasmon excitation with single nanoparticle is possible It is preferable because it has various advantages that iv) the absorption of an arbitrary specific wavelength from the visible region to the near infrared region can be selected by controlling the aspect ratio (long axis / short axis value).
By using such nanometer-sized fine particles, not only has excellent controllability of the wavelength used, but also the light energy converted into localized plasmons can be stored in a very small area on the nanoparticle surface. Light control in a region smaller than the diffraction limit can be realized.

<About Invention 6>
It is known that the enhancement effect by surface plasmons is influenced by the surrounding metal fine particles themselves. For example, it has been reported that when metal fine particles are brought close to each other, a very large plasmon enhancement field is generated between the particles. Forms such as dimers or small-scale aggregates in which two particles are combined in this way are also included as fine particle forms of the present inventions 1 to 5, from the viewpoint of improving the three-dimensional uniformity of characteristics. It is preferable that the number of the metal fine particles covered with the inorganic oxide is one, in other words, the metal fine particles are individually covered with the inorganic oxide [see FIG. 10 (a)]. Even if such metal fine particles are used alone, they can be efficiently coupled with light to generate plasmon oscillation due to free electrons, thereby forming an enhanced field. In addition, since the number of the metal microparticles | fine-particles coat | covered with the inorganic oxide is two or more, the form as shown in FIG.10 (b) is not included in this invention 6. FIG.

<About Invention 7>
The resonance frequency of the surface plasmon in the metal fine particle changes depending on the particle size and shape, and the dielectric constant of the surrounding medium, but as with the enhancement effect, it may change even under the influence of the metal fine particles present in the surroundings. Are known. Therefore, from the viewpoint that the resonance frequency of the plasmon can be controlled while maintaining the shape of the two-photon absorbing organic material or the metal fine particles, it is desirable that the metal fine particles are regularly arranged, and in particular, the metal fine particles are arranged in the same direction. Orientation is preferable because the resonance wavelength can be shifted (see FIG. 11A). An example in which they are not oriented in the same direction is shown in FIG.

<About Inventions 8 to 16>
In the present inventions 8 to 11, the mixture according to any one of the above inventions 1 to 7 is used for an optical recording material, an optical modeling material, an optical limiting material, and a two-photon excited fluorescent material.
In the inventions 12 to 16, the mixture of any of the inventions 1 to 7 is used for a three-dimensional optical recording medium, an optical modeling device, a light limiting device, and a two-photon excitation fluorescence detection device. This makes it easy to control the surface plasmon resonance frequency and the metal-material distance, which operates in the visible to near-infrared wavelength region, and can effectively utilize the plasmon enhancement effect, with three-dimensional characteristics. A new device excellent in uniformity and environmental stability can be provided.
Hereinafter, these will be described in more detail.

<Application to three-dimensional optical recording media>
Today's data archiving applications, with the expansion of networks such as the Internet and Intranet, popularization of high-definition TV with 1920 x 1080 (vertical x horizontal) dot image information amount, and HDTV (High Definition Television) coming soon In consumer use, a recording medium of 50 GB or more, preferably 100 GB or more is required. Further, as a backup application for computers and broadcast videos, a recording medium capable of recording large-capacity information of about 1 TB or more at high speed and at low cost is required.
Under such circumstances, a three-dimensional optical recording medium that is attracting attention as an ultimate high-density, large-capacity recording medium is a recording medium that can record / reproduce in the vertical and horizontal directions with respect to incident light. By stacking dozens or hundreds of recording layers in the direction, or by forming a thick film, it is possible to record and play back multiple times in the light incident direction. It is said to be a recording medium that has the possibility of ultra-high density and ultra-high-capacity recording that is tens or hundreds of times that of a two-dimensional recording medium.

As a three-dimensional optical recording medium using a two-photon absorption material, a method of reading with fluorescence using a fluorescent substance for recording and reproduction (the above-mentioned patent documents 1 and 2), a method of reading with absorption or fluorescence using a photochromic compound (the above-mentioned patent) Documents 3 to 4) have been proposed. However, since the photochromic compounds used in these patent documents are reversible materials, there are problems in non-destructive reading, long-term storage stability of recording, S / N ratio of reproduction, and the like, a method that is practical as an optical recording medium I can't say that.
In addition, Patent Documents 5 to 6 disclose a recording apparatus, a reproducing apparatus, a reading method, and the like that three-dimensionally records by refractive index modulation, but a method using a two-photon absorption three-dimensional optical recording material. There is no description about.
On the other hand, if non-resonant two-photon absorption is used and modulation is possible using a method that cannot rewrite the laser focus (recording) and non-focus (non-recording) parts, recording can be performed in any three-dimensional space with extremely high spatial resolution Thus, a three-dimensional optical recording medium that is an ultimate high-density recording medium can be realized. In addition, non-destructive readout is possible by using an irreversible material, and good storage characteristics can be maintained, which is more practical.

The optical recording material using the mixture of the present invention can be applied directly on the substrate by using a spin coater, roll coater or bar coater, or cast as a film, and then laminated on the substrate by a usual method. You can also. “Substrate” here means any natural or synthetic support, preferably one that can exist in the form of a flexible or rigid film, sheet or plate. The solvent used during solution preparation and coating can be removed by evaporation during drying, and heating or reduced pressure may be used for evaporation removal.
Preferable substrate materials include polyethylene terephthalate, resin-primed polyethylene terephthalate, polyethylene terephthalate subjected to flame or electrostatic discharge treatment, cellulose acetate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, glass and the like. In addition, a tracking guide groove and address information may be provided in advance on the substrate.

Furthermore, a protective layer (intermediate layer) for blocking oxygen and preventing interlayer crosstalk may be formed on the optical recording material according to the present invention. The protective layer (intermediate layer) is made of a plastic film or plate such as polypropylene, polyethylene, polyolefins such as polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate or cellophane film. Alternatively, the layers may be laminated together or the polymer solution may be applied. Further, a glass plate may be bonded. However, three-dimensional recording is possible without providing such a protective layer (intermediate layer).
Further, an adhesive or a liquid substance for enhancing airtightness may be present between the protective layer and the recording material and / or between the substrate and the recording material. Further, a guide groove for tracking and address information may be provided in advance in a protective layer (intermediate layer) between recording materials.

FIG. 1 shows an example of a three-dimensional optical recording medium (a) using the mixture of any one of the present inventions 1 to 7 as an optical recording material and a recording apparatus (b) thereof. However, the present invention is not limited in any way by these embodiments, and any other structure may be used as long as it can perform three-dimensional recording (recording in a plane and a film thickness direction).
FIG. 1A shows an example of a three-dimensional optical recording medium in which 50 recording layers 13a made of the mixture of the present invention and 50 intermediate layers 14a for preventing crosstalk are alternately laminated on a flat substrate 11a.
The recording layer 13a preferably has a thickness of 0.01 to 0.5 [mu] m, and the intermediate layer 14a preferably has a thickness of 0.1 to 5 [mu] m. Class high-capacity optical recording medium can be realized.
Three-dimensional recording of information is performed by focusing the light 15a generated from the light source 11b on a desired position in the recording layer 13a containing the mixture of the present invention. A single beam is used as the light source, and in this case, ultrashort pulse light of femtosecond order can be used. In addition to the bit-unit and depth-unit recording methods, a parallel recording method using a surface light source is preferable because it achieves a high transfer rate.

Although not shown here, in the three-dimensional recording medium of FIG. 1 (a), a bulk recording medium without an intermediate layer is produced, and page data is collectively recorded as in hologram recording, It is also possible to realize a high transfer rate.
Reproduction is performed by irradiating the recording unit and the non-recording unit with laser light having a lower intensity than that during recording, and detecting the change in light emission intensity or reflectance with the detector 13b. As the reproduction light, a light having a wavelength different from that of the beam used for data recording or the same wavelength with a low output can be used. Similar to recording, playback can be performed in bit units / page units, and parallel recording / playback using a surface light source, a two-dimensional detector, or the like is effective in increasing the transfer rate.
Note that the form of the optical recording medium similarly produced according to the present invention may be a card, plate, tape, drum or the like.

<Application as stereolithography method / apparatus>
The photo-curing resin for optical modeling is a resin having a property of causing a polymerization reaction when irradiated with light and changing from a liquid to a solid. The main components are a resin component consisting of an oligomer and a reactive diluent and a photopolymerization initiator (including a photosensitizing material as required). An oligomer is a polymer having a degree of polymerization of about 2 to 20, and has a large number of reactive groups at its ends. Furthermore, a reactive diluent is added to adjust viscosity, curability and the like.
When irradiated with light, the polymerization initiator or photosensitizing material absorbs light, and reactive species are generated directly from the polymerization initiator or through the photosensitizing material, and react with the reactive groups of the oligomer and reactive diluent. Polymerization is started. Thereafter, a chain polymerization reaction is caused between them to form a three-dimensional cross-link, and in a short time, a solid resin having a three-dimensional network structure is formed.
Photocurable resins are used in fields such as photocurable inks, photoadhesives, and layered three-dimensional modeling, and resins having various characteristics have been developed. In particular, in the layered three-dimensional modeling, it is important that the reactivity is good, the volume shrinkage during curing is small, and the mechanical properties after curing are excellent.
The mixture of the present invention can be used as a polymerization initiator or an absorption photosensitizing material that satisfies such requirements. Since the two-photon absorption material contained in the mixture of the present invention has higher photosensitivity than conventional ones, high-speed modeling is possible, and fine three-dimensional modeling can be realized.
In the present invention, the mixture of the present invention used as a photosensitizing material is dispersed in an ultraviolet curable resin or the like to form a photosensitive material solid, and light irradiation is performed on a desired portion of the photosensitive material solid. It is also possible to cause a curing reaction only in the vicinity of the focal point of to form an ultra-precise three-dimensional structure.

FIG. 2 is an example of an optical modeling apparatus in the case of performing optical modeling using any one of the mixtures 1 to 7 of the present invention.
When the pulsed laser light from the light source 21 is condensed on the two-photon absorption material 24 contained in the mixture of the present invention via the movable mirror 22 and the condenser lens 23, a region having a high photon density only in the vicinity of the condensing point. Is formed. At this time, since the total number of photons passing through each cross section of the beam is constant, when the beam is scanned two-dimensionally within the focal plane, the total light intensity in each cross section is constant. However, since the probability of occurrence of two-photon absorption is proportional to the square of the light intensity, a region where the generation of two-photon absorption is high is formed only near the condensing point where the light intensity is high. The condensing point can be freely changed in the photocurable resin liquid by controlling the movable mirror 22 and the movable stage 25 (galvanometer mirror and Z stage). The resin can be locally cured with accuracy, and a desired three-dimensional workpiece can be easily formed.
Moreover, an optical waveguide is shown in FIG.

In recent years, while a recording medium for large-capacity archives is demanded, an increase in information transmission speed and capacity is also demanded by development of optical fiber communication for realizing a ubiquitous network. One of them is known as WDM (Wavelength Multiplexing Communication), which is a large-capacity transmission technology that uses the incoherence of light with different wavelengths. In this WDM, optical signals of specific wavelengths are combined or An element for demultiplexing is indispensable, and an optical waveguide is used as an element for that purpose. In the optical waveguide, by forming a specific refractive index distribution or the like inside the element, an optical signal can be guided along the distribution so that electrons flow in the electric circuit. The optical waveguide structure using the refractive index change due to such a wavelength uses the optical modeling apparatus shown in FIG. 2, and the thin film containing the mixture of the present invention described in any one of claims 1 to 7, or of the present invention It can form by carrying out the optical modeling of the solid substance which disperse | distributed the mixture to photocurable resin etc.
As a known document useful for understanding the optical modeling in the present invention, Patent Document 7 is cited. According to this, pulsed laser light is subjected to interference exposure on the surface of the photosensitive polymer material film without using a mask. The laser beam consists of light having a wavelength component that exerts the photosensitive function of the photosensitive polymer material film, and is applied to the type of photosensitive polymer material or the group or site having the photosensitive function of the photosensitive polymer material. Is selected accordingly.
Further, as publicly known documents relating to optical waveguides, the above-mentioned Patent Documents 8 to 11 disclose optical waveguides formed by irradiating light to a photorefractive index material.

Compared to such a conventional one, the optically shaped object using the mixture of the present invention has the following features (i) to (v).
(I) Processing resolution exceeding the diffraction limit Due to the non-linearity of the two-photon absorption with respect to the light intensity, the photo-curable resin is not cured in a region other than the focal point. For this reason, processing resolution exceeding the diffraction limit of irradiation light is realizable.
(Ii) Ultra-high-speed modeling In a modeled object processed using the mixture of the present invention, since the two-photon absorption sensitivity is higher than the conventional one, the beam scanning speed can be increased.
(Iii) Three-dimensional processability The photocurable resin is transparent to near-infrared light that induces two-photon absorption. Therefore, internal curing is possible even when the focused light is condensed deeply into the resin. In the conventional processing technique that does not use the two-photon absorption phenomenon, when the beam is condensed deeply, there is a problem that the light intensity at the condensing point becomes small due to light absorption and internal hardening becomes difficult. These problems can be solved reliably.
(Iv) High Yield In the conventional method, there is a problem that the modeled object is damaged or deformed due to the viscosity or surface tension of the resin. However, in the present invention, such a problem is solved because modeling is performed inside the resin.
(V) Application to mass production By using ultra-high-speed modeling, a large number of parts or movable mechanisms can be manufactured continuously in a short time.

<Application as light limiting method and device>
In optical communication and optical information processing, optical control such as modulation and switching is required to carry signals such as information with light. For this type of light control, conventionally, an electro-light control method using an electric signal has been adopted. However, the electro-optical control method has a processing speed (> 10 ps) because the band is limited by the CR time constant as in an electric circuit, the response speed of the element itself, and the unbalance of the speed between the electric signal and the optical signal. ) Is limited, and the light-light control technology that controls the optical signal by the optical signal becomes very important in order to make full use of the broadband property and high speed that are the advantages of light. come. An optical element manufactured by processing the mixture of the present invention in response to this requirement uses an electronic circuit technology by utilizing optical changes such as transmittance, refractive index, and absorption coefficient caused by light irradiation. Without directly modulating the intensity or frequency of light with light, it can be applied to a high-speed optical switch in optical communication, optical exchange, optical computer, optical interconnection, and the like.

The light limiting element of the present invention that utilizes the change in optical characteristics due to two-photon absorption is a light limiting element formed of a normal semiconductor material, or an element having a much faster response speed than that of one-photon excitation (< 1 ps), and because of its high sensitivity, it is possible to provide an optical limiting element excellent in signal characteristics with a high S / N ratio.
Examples of conventional optical limiting elements utilizing single-photon absorption or supersaturated absorption include spectral hole burning, exciton absorption, intersubband transition, quantum confinement chattalc effect, etc. There are problems in that it is difficult to obtain a high-speed response, device fabrication (composition, structure) is complicated, the corresponding wavelength range is narrow, and there are many systems with large polarization dependence.
On the other hand, in the optical limiting element using the nonlinearity of two-photon absorption, it is excellent in ultra-high-speed response, easy to manufacture (composition, structure), wide wavelength range, wide wavelength selection, polarization dependence There is an advantage that there is no sex.

FIG. 4 shows an element that switches the signal light having a wavelength that can be excited by one photon by two-photon excitation of the mixture according to any one of the present inventions 1 to 7 with control light having a specific wavelength.
The laser light incident from the control light 41 and the signal light 42 is collected by a light collecting device 43 (lens, concave mirror, etc.), and the mixture of the present invention sandwiched between protective layers only when the intensity of the control light 41 is extremely high. And the transmittance of the one-photon excitation wavelength changes. When the intensity of the control light 42 is not strong or weak, it passes through as it is, and is detected by the photodetector 47 on the emission side through a color filter 46 etc. that removes stray light by a collimator device 45 (lens, concave mirror, etc.). That is, by utilizing the change in transmittance due to the nonlinearity of two-photon absorption in this way, it is possible to perform optical switching with high-speed response in which signal light is processed with the intensity of control light.
FIG. 5 shows an operation example of a light control element that performs two-photon excitation of the mixture of any one of the first to seventh aspects of the present invention with signal light and control light and performs all-optical switching. (A) shows the relationship between the light limiting element and control light, signal light, and output light, and (b) shows the relationship between signal light, control light, output light, and switching.
The control light and the signal light are condensed on the light limiting element having the mixture of the present invention as a main component by the condensing device [FIG. 5 (a)], and when the control light is off, the signal light is output as it is, When the control light is on, two-photons are absorbed together with the signal light and no output is output [FIG. 5 (b)]. By switching on / off the control light, optical switching of the signal light becomes possible.

FIG. 6 shows an example of a light control element that switches the optical path of output light by two-photon excitation of the mixture of any one of the present inventions 1 to 7 with control light having a wavelength capable of two-photon excitation. (A) and (b) are examples in which the incident directions of the control light are different.
The laser light incident from the control light and the signal light is focused on the branch path portion of the optical waveguide whose main component is the mixture of the present invention by the condensing device, and is branched only when the intensity of the control light is extremely strong. It is absorbed by the road part and the refractive index of the part changes. The optical path of the output light can be switched by adjusting the refractive index change of the branch path portion of the optical waveguide due to two-photon absorption, the refractive index of the optical waveguide of the signal light, and the refractive index of the optical waveguide of the output light. By utilizing the change in the refractive index accompanying the nonlinearity of two-photon absorption, it becomes possible to switch the optical path, for example, in an optical waveguide.
Known documents useful for understanding the light limiting element in the present invention include Patent Documents 12 to 14, but the optical functional element using the mixture of the present invention is an element formed of a normal semiconductor material or the like. Compared with a device using one-photon excitation of a material, the device has excellent signal characteristics such as a much faster response speed, higher sensitivity, and a higher S / N ratio.

<Application as a two-photon excitation fluorescence detection method / apparatus>
The two-photon excitation fluorescence detection method is a two-photon excited material that is scanned by focusing a near-infrared pulse laser on a sample containing an analyte labeled with a two-photon fluorescent material. It is a detection method that obtains an image three-dimensionally by detecting the fluorescence that is sometimes generated. FIG. 7 shows a two-photon excitation fluorescence microscope as an example of such a light detection device.
The apparatus shown in FIG. 7 generates laser light from a light source 71 that generates sub-picosecond monochromatic coherent pulses in the near-infrared wavelength region, and condenses the light by a condensing device 73 via a dichroic mirror 72, in the mixture of the present invention. Two-photon fluorescence is generated by focusing in the sample 74 containing the analyte to which the two-photon absorbing material contained in the sample is bound. A three-dimensional fluorescent image can be obtained by manipulating the laser beam on the sample, detecting the fluorescence intensity at each location with the photodetector 76, and plotting the fluorescence intensity and the obtained position information on a computer. . In this case, the microscope is provided with a scanning mechanism for scanning a desired condensing position with a laser beam. For example, a sample placed on the stage 75 may be moved, and a movable mirror (galvano mirror) may be moved. Etc.) may be used to scan the laser beam.
The two-photon excitation fluorescence microscope having such a configuration can obtain a high-resolution image in the optical axis direction, but by using a confocal pinhole plate, the resolution can be further increased in both the in-plane and optical axis directions. .

The two-photon fluorescent material used in this way can be used by staining an analyte or being dispersed in the analyte, and is used not only for industrial use but also for three-dimensional image microimaging of living cells and the like. be able to. It can also be used as a photosensitive material in photodynamic therapy (PDT) by mixing with a biocompatible polymer.
As a known document useful for understanding the above-described two-photon excitation fluorescence microscope, Patent Document 15 is cited. For example, a scanning fluorescent microscope includes a laser irradiation optical system that emits collimated light expanded to a desired size, and a substrate on which a plurality of condensing elements are formed. A beam splitter that transmits a long wavelength and reflects a short wavelength is disposed between the substrate on which the light condensing element is formed and the objective lens system, so as to coincide with the image position of the system. The surface is characterized by generating fluorescence by two-photon absorption. With such a configuration, it is possible to obtain high resolution in the optical axis direction by utilizing the nonlinear effect of two-photon absorption itself. In addition, if a confocal pinhole plate is used, higher resolution (both in-plane and in the optical axis direction) can be obtained.
According to the mixture of the present invention, the sensitivity is higher than that of the conventional two-photon excitation fluorescent material, so that it is not necessary to increase the light intensity applied to the sample, and deterioration and destruction of the sample can be suppressed. In particular, when applied to a living body, damage to the living body can be reduced.

  According to the present invention, it is easy to control the resonance frequency of the surface plasmon and the distance between the metal and the material using the interaction between the photoelectric field in the visible to near-infrared wavelength region and the surface plasmon, and the plasmon enhancement effect is effective. It is possible to provide a mixture excellent in three-dimensional property uniformity and environmental stability, and a plasmonics device using the mixture.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not restrict | limited at all by these Examples. 9A to 9H, which will be described later, have a major axis length of about 30 to 50 nm and a minor axis length of about 10 nm. Further, the film thickness of the silicon oxide covering the surface is all in the range of about 8 to 15 nm. However, the film thickness of the silicon oxide can be controlled in the range of about 5 to 30 nm. Further, although not shown in the figure, when the fine particles are spherical, the diameter is preferably about 20 nm.

Example 1
<Synthesis of gold nanorods>
To 500 mL of a 0.18 mol aqueous solution of CTAB (cetyltrimethylammonium bromide), while stirring, 3.0 mL of cyclohexanone, 1.5 mL of diisobutyl ketone, 39.0 mL of 0.024 mol aqueous solution of chloroauric acid, and 0.01 mol aqueous solution of silver nitrate 15. 0 mL was sequentially added, and a 0.1 mol aqueous solution of ascorbic acid was added dropwise with stirring until the color of chloroauric acid disappeared.
Next, 7.0 mL of a 0.1 mol aqueous solution of ascorbic acid was further added dropwise while irradiating the solution with ultraviolet light under a low-pressure mercury lamp, to obtain an aqueous solvent-dispersed rod-shaped gold fine particle solution protected with CTAB. Thereafter, centrifugation (7000 G, 60 min) was repeated a plurality of times to remove excess CTAB.
Next, this rod-shaped gold fine particle solution was dropped into a 6.0 mmol aqueous solution of NaCl containing 2.0 g / L of poly (sodium 4-styrenesulfonate) (molecular weight 70,000, hereinafter referred to as PSS) as a polycation. Excess PSS was removed by centrifugation (7000 G, 60 min) to obtain rod-shaped PSS-coated gold fine particles.
Next, the rod-shaped PSS-coated gold fine particles were dropped into a 6.0 mmol aqueous solution of NaCl containing 2.0 g / L of poly (allylamine hydrochloride) (molecular weight: 15,000, hereinafter referred to as PAH) as a polyanion, PAH was removed by centrifugation (7000 G, 60 min) to obtain rod-shaped PAH-coated gold fine particles.
Next, the rod-shaped PAH-coated gold fine particles were dropped into a 4.0 g / L aqueous solution of poly (vinyl pyrrolidone) (molecular weight: 35,000, hereinafter referred to as PVP) for stabilization of the polymer film, and then excess PVP. Was removed by centrifugation (7000 G, 60 min), and finally a precipitate of rod-shaped gold fine particles coated with three kinds of water-soluble polymers of PSS, PAH, and PVP was obtained.
Next, this precipitate was dispersed in 2-propanol at a volume ratio of 1: 5.
Next, 2.5 mL of this dispersion liquid was added to 2.0 mL of a 0.97 vol% solution of TEOS (tetraethoxysilane) using 2-propanol as a solvent, and 2-propanol containing 3.84 vol% of a 33.0 wt% aqueous solution of ammonia. The solution was dropped into a mixed solution consisting of 3.0 mL of the solution and stirred for 3 hours.
After stirring, unreacted TEOS was removed from the 2-propanol dispersion by centrifugation (6500 G, 60 min) to obtain a precipitate of rod-shaped silicon oxide-coated gold fine particles. [A TEM (transmission electron microscope) image of the rod-shaped silicon oxide-coated gold fine particles is shown in FIG. 9A. ]
The precipitate was then redispersed in ethanol so that the absorbance at the plasmon resonance wavelength was 0.8.
Next, 3.0 mL of this solution is added dropwise to a mixed solution consisting of 300 μL of a 2.4 mol% solution of OTMS (octadecyltrimethoxysilane) using chloroform as a solvent and 30 μL of a 33.0 wt% aqueous solution of ammonia, and stirring is continued overnight. Thus, non-aqueous solvent dispersion type rod-shaped silicon oxide coated gold fine particles were obtained.
Finally, 3 mg of this non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7 mg of a two-photon absorbing organic material shown in the following [Chemical Formula 1], and then this solution is spin-coated. Was applied onto a glass substrate to prepare a thin film sample having a thickness of 200 nm.

(Example 2)
The same non-aqueous solvent dispersion type rod-shaped silicon oxide-coated gold fine particles 3 mg as in Example 1 were redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorption organic material shown in the following [Chemical Formula 2], A thin film sample having a thickness of 200 nm was prepared by applying onto a glass substrate by spin coating. (A TEM image of the non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particles used here is shown in FIG. 9B.)

(Example 3)
As in Example 1, an aqueous solvent-dispersed rod-shaped gold fine particle solution from which excess CTAB was removed by centrifugation was used as a polyanion, which contained 2.0 g / L of polyvinyl phosphate (hereinafter referred to as PVPA, molecular weight 90,000) as a polyanion. Then, excessive PVPA was removed by centrifugation (7000 G, 60 min) to obtain a precipitate of rod-shaped gold fine particles coated with one kind of PVPA water-soluble polymer.
Thereafter, following the same procedure as in Example 1, non-aqueous solvent dispersion type rod-shaped silicon oxide-coated gold fine particles were obtained.
Finally, 3 mg of this non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7.0 mg of the two-photon absorption organic material shown in the above [Chemical Formula 1]. A thin film sample having a thickness of 200 nm was prepared by applying the film on a glass substrate by spin coating. (A TEM image of the non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particles used here is shown in FIG. 9C.)

Example 4
A rod coated with three water-soluble polymers of PSS, PAH, and PVP according to the same procedure as in Example 1 except that the centrifugation conditions for removing excess PSS, PAH, and PVP were changed to 6000 G, 30 min. A precipitate of fine gold particles was obtained.
Next, this precipitate was dispersed in 2-propanol at a volume ratio of 1: 5.
Next, 2.5 mL of 2-propanol was added to 2.0 mL of a 0.97 vol% TEOS solution using 2-propanol as a solvent, and while stirring vigorously, 2.5 mL of the precipitate dispersion was added dropwise thereto. Furthermore, 0.3 mL of 2-propanol solution containing 3.84 vol% of 33.0 wt% aqueous solution of ammonia was added as a catalyst and stirred for 1.5 hours.
After stirring, unreacted TEOS was removed from the 2-propanol dispersion by centrifugation (6000 G, 30 min), and then the non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particles were added according to the same procedure as in Example 1. Obtained. (A TEM image of this non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particle is shown in FIG. 9D.)

(Example 5)
A precipitate of rod-shaped gold fine particles coated with PVPA was obtained according to the same procedure as in Example 3 except that the centrifugation conditions for removing excess PVPA were changed to 6000 G and 30 min.
Next, this precipitate was dispersed in 2-propanol at a volume ratio of 1: 5.
Next, 2.5 mL of 2-propanol was added to 2.0 mL of a 0.97 vol% TEOS solution using 2-propanol as a solvent, and while stirring vigorously, 2.5 mL of the precipitate dispersion was added dropwise thereto. Furthermore, 0.3 mL of 2-propanol solution containing 3.84 vol% of 33.0 wt% aqueous solution of ammonia was added as a catalyst and stirred for 1.5 hours.
After stirring, unreacted TEOS was removed from the 2-propanol dispersion by centrifugation (6000 G, 30 min), and then the non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particles were added according to the same procedure as in Example 1. Obtained. (A TEM image of this non-aqueous solvent-dispersed rod-shaped silicon oxide-coated gold fine particle is shown in FIG. 9E.)

(Example 6)
After removing unreacted TEOS from the 2-propanol dispersion obtained according to the same procedure as in Example 4 by centrifugation (6500 G, 60 min), dispersion in 2-propanol and centrifugation were performed while optimizing the centrifugation conditions. The precipitates of rod-shaped gold fine particles coated with silicon oxide and purified in the same direction and separated in the same direction were separated. (A TEM image of this rod-shaped silicon oxide-coated gold fine particle is shown in FIG. 9F.)
Next, the obtained precipitate was redispersed in ethanol so that the absorbance at the plasmon resonance wavelength was 0.8.
Next, 3.0 mL of this solution was dropped into a mixed solution consisting of 300 μL of a 2.4 mol% OTMS solution containing chloroform as a solvent and 30 μL of a 33.0 wt% aqueous solution of ammonia, and the mixture was stirred for a whole day and night to disperse the nonaqueous solvent. Type rod-shaped silicon oxide-coated gold fine particles were obtained.
Finally, 3 mg of this non-aqueous solvent dispersion type rod-shaped silicon oxide coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorption organic material shown in the above [Chemical Formula 1], and then this solution is spin-coated. Was applied onto a glass substrate to prepare a thin film sample having a thickness of 200 nm.

(Example 7)
A precipitate of rod-shaped gold fine particles coated with the same PSS, PAH, and PVP as in Example 1 was dispersed in 2-propanol at a volume ratio of 1: 5.
Next, 2.5 mL of this dispersion liquid was added to 2.0 mL of a 1.0 vol% tetraisopropyl titanate solution using 2-propanol as a solvent, and 3.0 mL of a 2-propanol solution containing 3.84 vol% of a 33.0 wt% aqueous solution of ammonia. The solution was dropped into the mixed solution consisting of and stirred for 3 hours.
After stirring, unreacted tetraisopropyl titanate was removed from the 2-propanol dispersion by centrifugation (6500 G, 60 min) to obtain a precipitate of rod-shaped titanium oxide-coated gold fine particles.
Finally, 3 mg of this non-aqueous solvent-dispersed rod-shaped titanium oxide-coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorption organic material shown in the above [Chemical Formula 1], and then the solution is spun. A thin film sample having a thickness of 200 nm was produced by coating on a glass substrate by coating.

(Example 8)
A precipitate of rod-shaped gold fine particles coated with the same PSS, PAH, and PVP as in Example 1 was dispersed in 2-propanol at a volume ratio of 1: 5.
Next, 2.5 mL of this dispersion liquid was added to 2.0 mL of a 1.0 vol% n-propyl zirconate solution using 2-propanol as a solvent, and 2-propanol solution 3 containing 3.84 vol% of a 33.0 wt% aqueous solution of ammonia. Dropped into a mixed solution consisting of 0.0 mL, and stirred for 3 hours.
After stirring, unreacted n-propyl zirconate was removed from the 2-propanol dispersion by centrifugation (6500 G, 60 min) to obtain a precipitate of rod-shaped zirconium oxide-coated gold fine particles.
Finally, 3 mg of this non-aqueous solvent-dispersed rod-shaped zirconium oxide-coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorbing organic material shown in [Chemical Formula 1], and then this solution is spin-coated. Was applied onto a glass substrate to prepare a thin film sample having a thickness of 200 nm.

Example 9
A precipitate of rod-shaped gold fine particles coated with the same PSS, PAH, and PVP as in Example 1 was dispersed in 2-propanol at a volume ratio of 1: 5.
Then, 2.5 mL of this dispersion liquid was added to 2.0 mL of a 1.0 vol% ethyl acetoacetate aluminum diisopropylate solution using 2-propanol as a solvent, and 2-propanol containing 3.84 vol% of a 33.0 wt% aqueous solution of ammonia. The solution was dropped into a mixed solution consisting of 3.0 mL of the solution and stirred for 3 hours.
After stirring, unreacted ethyl acetoacetate aluminum diisopropylate was removed from the 2-propanol dispersion by centrifugation (6500 G, 60 min) to obtain a precipitate of rod-shaped aluminum oxide-coated gold fine particles.
Finally, 3 mg of this non-aqueous solvent-dispersed rod-shaped aluminum oxide-coated gold fine particle is redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorbing organic material shown in the above [Chemical Formula 1], and then this solution is spin-coated. Was applied onto a glass substrate to prepare a thin film sample having a thickness of 200 nm.

(Example 10)
The same non-aqueous solvent dispersion type rod-shaped silicon oxide-coated gold fine particles 3 mg as in Example 1 were re-dispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorption organic material shown in the following [Chemical Formula 3]. A thin film sample having a thickness of 200 nm was prepared by applying the film on a glass substrate by spin coating.

(Example 11)
The same non-aqueous solvent dispersion type rod-shaped silicon oxide-coated gold fine particles 3 mg as in Example 1 were redispersed in 10 mL of toluene and mixed with 7 mg of the two-photon absorption organic material shown in the following [Chemical Formula 4], A thin film sample having a thickness of 200 nm was prepared by applying the film on a glass substrate by spin coating.
(In the above formula, [] is a repeating unit, and n represents a natural number.)
This polymer had a polystyrene-reduced number average molecular weight of 48,200 and a weight average molecular weight of 134,600 as measured by GPC (gel permeation chromatography).

(Comparative Example 1)
In Example 1, when obtaining an aqueous solvent-dispersed rod-shaped gold fine particle solution protected with CTAB, a 0.1 mol aqueous solution of ascorbic acid was added dropwise while irradiating with ultraviolet light under a low-pressure mercury lamp, followed by centrifugation (7000 G, 60 min) was repeated a plurality of times to remove excess CTAB, and then mixed with a 1.0 mol% toluene solution of 3-aminopropylethyldiethoxysilane and stirred to disperse the rod-shaped gold fine particles in the toluene layer. At this time, rod-shaped gold fine particles dispersed in the toluene layer were collected and observed by TEM. The result is shown in FIG. 9H.
This solution was adjusted so that 3 mg of rod-shaped gold fine particles were contained in 1 mL, mixed with 1 mL of the solution and 7 mg of the two-photon absorption organic material shown in the above [Chemical Formula 1], and this solution was spin-coated to form a glass substrate. A thin film sample having a thickness of 200 nm was prepared by applying the film on the top.

(Comparative Example 2)
In Example 1, when obtaining an aqueous solvent-dispersed rod-shaped gold fine particle solution protected with CTAB, a 0.1 mol aqueous solution of ascorbic acid was added dropwise while irradiating with ultraviolet light under a low-pressure mercury lamp, followed by centrifugation (7000 G, 60 min) was repeated a plurality of times to remove excess CTAB, and then mixed with a 1.0 mol% toluene solution of 3-mercaptopropyltriethoxysilane and stirred to disperse the rod-shaped gold fine particles in the toluene layer.
This solution was adjusted so that 3 mg of rod-shaped gold fine particles were contained in 1 mL, mixed with 1 mL of the solution and 7 mg of the two-photon absorption organic material shown in the above [Chemical Formula 2], and this solution was spin-coated to form a glass substrate. A thin film sample having a thickness of 200 nm was prepared by applying the film on the top.

(Comparative Example 3)
In Example 1, when obtaining an aqueous solvent-dispersed rod-shaped gold fine particle solution protected with CTAB, a 0.1 mol aqueous solution of ascorbic acid was added dropwise while irradiating with ultraviolet light under a low-pressure mercury lamp, followed by centrifugation (7000 G, 60 min) was repeated a plurality of times to remove excess CTAB, and then mixed with a 1.0 mol% toluene solution of 3-aminopropylethyldiethoxysilane and stirred to disperse the rod-shaped gold fine particles in the toluene layer.
This solution was adjusted so that 3 mg of rod-shaped gold fine particles were contained in 1 mL, and 1 mL of the solution was mixed with 7 mg of the two-photon absorption organic material shown in the above [Chemical Formula 3]. A thin film sample having a thickness of 200 nm was prepared by applying the film on the top.

The thin film samples produced in the above examples and comparative examples were evaluated as follows.
(Evaluation method)
Evaluation of the photosensitivity enhancement effect by plasmons was performed by measuring the “fluorescent light amount” of the two-photon absorption material contained in the mixture of the present invention as an alternative characteristic.
Originally, it is more direct to evaluate the “two-photon absorption efficiency” of the two-photon absorption material contained in the mixture of the present invention as an alternative characteristic, but the measurement of the two-photon absorption efficiency is technically very much. There is a problem that it is difficult and measurement accuracy is low. Therefore, in the production of the thin film samples of the above examples and comparative examples, a material having fluorescence characteristics is used as the two-photon absorption organic material, and the amount of fluorescence generated as a result of the two-photon absorption is evaluated as an alternative characteristic of the enhancement effect. It was to be.
FIG. 8 shows a schematic diagram of a measurement system for the amount of fluorescent light.
As the excitation light source for two-photon absorption, MaiTai (infrared femtosecond laser, repetition frequency 80 MHz, pulse width 100 fs) manufactured by Spectra Physics was used.
In order to adjust the output, an attenuator composed of a λ / 2 plate and a gran laser prism was provided, and the average output was adjusted to 200 mW. After adjusting the output, the excitation light was converted into circularly polarized light through a λ / 4 plate and condensed inside the installed sample by a plano-convex lens having a focal length of 100 mm. Fluorescence generated at the focal point of the excitation light is condensed by a coupling lens having a focal length of 40 mm to be approximately parallel light, separated from the excitation light by a dichroic mirror, and further passed through an infrared cut glass filter, with a focal length of 100 mm. After being roughly condensed with a plano-convex lens, it was detected with a photodiode.

(Evaluation results)
The evaluation results are shown in Table 1.
The evaluation in the column of characteristics is the ratio of the measured two-photon fluorescence light amount of the measured example to the two-photon fluorescence light amount of the comparative example, and E (Excellent), 1.0 or more when the value is 1.5 or more. G (Good) was defined as less than 1.5.
In addition, Examples 1-9 were determined by the ratio with Comparative Example 1, Example 10 by the ratio with Comparative Example 2, and Example 11 by the ratio with Comparative Example 3, respectively.
In the evaluation of the uniformity column, when the measurement location is changed, the case where the two-photon fluorescence amount fluctuates by 30% or more is F (Fail), and the case where it fluctuates in the range of 10% or more and less than 30% is G (Good). ) E (E: Excellent) was defined as a variation of less than 10%.
The evaluation in the storage property (environmental stability) column is when the dispersion property of the inorganic oxide-coated metal fine particles in 2-propanol is evaluated as an alternative property, and the 2-propanol dispersion solution of the fine particles is left at room temperature for one week. F (Fail) when the fine particles are aggregated, G (Good) when the aggregate is slightly observed in a part of the solution, and maintaining a uniform dispersion without any change E (Excellent).
From Table 1, it can be seen that the mixture of the present invention can effectively bring out the plasmon enhancing effect as compared with the conventional case, and can improve the uniformity of characteristics and the storage characteristics of metal fine particles.

The figure which shows an example of the three-dimensional optical recording medium which utilizes the mixture in any one of this invention 1-7 as an optical recording material, and its recording device. (A) a three-dimensional optical recording medium, (b) a recording apparatus. The figure which shows an example of the optical modeling apparatus in the case of performing optical modeling using the mixture in any one of this invention 1-7. The figure which shows the optical waveguide as an example of the molded article produced with an optical modeling apparatus. The figure which shows an example of the light control element which optically switches the signal light of the wavelength which can carry out one-photon excitation by carrying out the two-photon excitation of the mixture in any one of this invention 1-7 with the control light of the wavelength which can carry out two-photon excitation . The figure which shows the operation example of the light control element which carries out all the optical switching which carries out the two-photon excitation of the mixture in any one of this invention 1-7 with signal light and control light. (A) The figure which shows the relationship between a light limiting element, control light, signal light, and output light, (b) The figure which shows the relationship between signal light, control light, output light, and switching. The figure which shows an example of the light control element which optically switches the optical path of output light by carrying out the two-photon excitation of the mixture in any one of this invention 1-7 with the control light of the wavelength which can carry out a two-photon excitation. (A) (b) is an example from which the incident direction of control light differs. The figure which shows an example of a two-photon excitation fluorescence microscope. The schematic diagram of the measurement system used by evaluation of an example. TEM image of inorganic oxide-coated gold fine particles. The figure explaining the form of the metal microparticle of this invention 6. (A) A form corresponding to the present invention 6 and (b) a form not corresponding to the present invention 6. The figure explaining the form of the metal microparticle of Claim 7. (A) A form corresponding to the present invention 7, (b) a form not corresponding to the present invention 7.

Explanation of symbols

11a Substrate (support)
11b Light source 12a Substrate (support)
12b Light source 13a Recording layer 13b Detector 14a Intermediate layer (protective layer)
14b Pinhole 15a Light 21 Light source 22 Movable mirror 23 Condensing lens 24 Two-photon absorption material 25 Movable stage 41 Control light 42 Signal light 43 Condensing device 44 Optical filter 45 Collimating device 46 Color filter 47 Detector,
71 Light source 72 Dichroic mirror 73 Condensing device 74 Sample 75 Stage 76 Photodetector

Claims (16)

  A mixture comprising metal fine particles having a surface coated with a polymer material and a surface coated with an inorganic oxide, and a two-photon absorbing organic material.   The mixture according to claim 1, wherein the polymer material is water-soluble.   The mixture according to claim 1 or 2, wherein the polymer material is an electrolyte.   The mixture according to claim 1, wherein the metal fine particles are gold.   The mixture according to any one of claims 1 to 4, wherein the shape of the metal fine particles is a rod shape having a nanometer size.   The mixture according to any one of claims 1 to 5, wherein the number of metal fine particles covered with the inorganic oxide is one.   The mixture according to any one of claims 1 to 5, wherein the metal fine particles contained in one particle of the inorganic oxide are oriented in the same direction.   An optical recording material comprising the mixture according to claim 1.   The optical modeling material characterized by including the mixture in any one of Claims 1-7.   A light limiting material comprising the mixture according to claim 1.   A two-photon excited fluorescent material comprising the mixture according to claim 1.   A three-dimensional optical recording medium having a recording layer formed on a plane and capable of recording / reproducing on the plane and in a direction perpendicular to the plane, the mixture according to any one of claims 1 to 7 performs optical recording. A three-dimensional optical recording medium characterized by being included as at least a part of a recording layer.   In the optical modeling apparatus which performs optical modeling by irradiating the laser beam condensed on photocurable resin, the mixture in any one of Claims 1-7 is contained as at least one part of the said photocurable resin. An optical modeling apparatus characterized by comprising:   In the light limiting apparatus provided with the element which restrict | limits the light transmission light intensity | strength of signal light with control light, The mixture in any one of Claims 1-7 is contained as at least one part of the said element. Light limiting device.   In the optical limiting device provided with the element which restricts the course of the light of signal light with control light, the mixture according to any one of claims 1 to 7 is included as at least a part of the element, Light limiting device.   A two-photon fluorescence of a two-photon absorption material contained in the mixture by selectively carrying the mixture according to any one of claims 1 to 7 on an analyte in a sample and irradiating the analyte with light. A two-photon excitation fluorescence detection apparatus characterized by having a function of detecting an analyte by expressing light and detecting the light.