JP2010217579A - Two-photon absorbing material and application therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency two-photon absorbing material for attaining practical applications using two-photon absorption by the use of a small inexpensive laser, to provide a two-photon absorption recording and reproducing method, in which after non-rewritable recording is carried out, using two-photon absorption of a two-photon absorption material that contains an electron-withdrawing compound having a high ionization potential and a pi-electron conjugate two-photon absorption compound having an electron donating group and thereby chemically amplified by the electron withdrawing compound, the information is reproduced by irradiating the recording material with light and detecting the difference in the intensity of the light emission of the material, to provide a two-photon absorption optical recording material allowing the recording and reproducing, and moreover, and to provide a two-photon absorption three-dimensional optical recording material, a two-photon absorption three-dimensional optical recording method and reproducing method using the material. <P>SOLUTION: The two-photon absorbing material contains an electron-withdrawing compound and a two-photon absorption compound comprising a non-cyclic pi-electron conjugate system at least one end terminal of which is modified with an electron-donating group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a two-photon absorption material, and relates to a two-photon absorption material having a high two-photon absorption cross section. The present invention also relates to uses such as a three-dimensional memory material, a light limiting material, a photocuring resin curing material, a photochemotherapy material, and a fluorescent dye material for a two-photon fluorescence microscope.

  A two-photon absorption material is a material that can excite molecules at a wavelength in the non-resonant region, and has a real excited state at an energy level twice that of the photon used for excitation. is there.

  By the way, the two-photon absorption phenomenon is a kind of third-order nonlinear optical effect, which is a phenomenon in which a molecule absorbs two photons simultaneously and transitions from a ground state to an excited state. Since Luc Bredas et al. Elucidated the relationship between molecular structure and mechanism in 1998 (Science, 281, 1653 (1998)), research on materials having two-photon absorption ability has recently advanced.

  However, the transition efficiency of such two-photon simultaneous absorption is extremely low compared with one-photon absorption and requires extremely high power density photons. It has been confirmed that an ultra-short pulse laser of about femtosecond such as a mode-locked laser having high intensity (light intensity at the maximum emission wavelength) is used.

  The transition efficiency of two-photon absorption is proportional to the square of the applied photoelectric field (the two-photon absorption square characteristic). For this reason, when a laser is irradiated, two-photon absorption occurs only at a position where the electric field strength is high at the center of the laser spot, and no two-photon absorption occurs at a portion where the electric field strength is weak at the peripheral portion. In the three-dimensional space, two-photon absorption occurs only in a region where the electric field strength at the focal point where the laser light is collected by the lens is large, and no two-photon absorption occurs in the region outside the focal point because the electric field strength is weak. Compared to the linear absorption of one photon where excitation occurs at all positions in proportion to the intensity of the applied photoelectric field, the two-photon absorption is excited only at a pinpoint inside the space due to this square characteristic. Therefore, the spatial resolution is significantly improved.

  Utilizing this characteristic, research on a three-dimensional memory for recording bit data by causing a spectral change, a refractive index change or a polarization change by two-photon absorption at a predetermined position of a recording medium is underway. Since two-photon absorption occurs in proportion to the square of the intensity of light, a memory using two-photon absorption can reduce the spot size compared to a memory using one-photon absorption, and super-resolution recording. Is possible. In addition, from the characteristics of high spatial resolution derived from this square characteristic, development for applications such as a light limiting material, a cured material of a photo-curing resin for stereolithography, and a fluorescent dye material for a two-photon fluorescence microscope is being promoted.

  Furthermore, in the case of inducing two-photon absorption, it is possible to use a short-pulse laser in the near-infrared region that has a longer wavelength than the wavelength region in which the linear absorption band of the compound exists and does not have absorption. Since the near-infrared light of the so-called transparent region, which does not have a linear absorption band of the compound, is used, the excitation light can reach the inside of the sample without being absorbed or scattered, and because of the square characteristic of the two-photon absorption, Since pinpoints can be excited with high spatial resolution, two-photon absorption and two-photon emission are also expected in photochemotherapy applications such as two-photon contrast and two-photon photodynamic therapy (PDT) in biological tissues. In addition, research on upconversion lasing has been reported from the viewpoint of a wavelength conversion device because photons with higher energy than the energy of incident photons can be extracted by using two-photon absorption and two-photon emission.

  Many inorganic materials have been found so far as two-photon absorption materials. However, inorganic materials are very difficult to put into practical use because so-called molecular design for optimizing desired two-photon absorption characteristics and various physical properties necessary for device manufacture is difficult. On the other hand, organic compounds can be optimized not only for the desired two-photon absorption by molecular design, but also for other physical properties, making it highly practical and a promising two-photon absorption material. It attracts attention.

  As conventional organic two-photon absorption materials, pigment compounds such as rhodamine and coumarin, compounds such as dithienothiophene derivatives and oligophenylene vinylene derivatives are known. However, the two-photon absorption cross section showing the two-photon absorption capacity per molecule is small, and the two-photon absorption cross-section when using a femtosecond pulse laser is 200 (GM: × 10-50cm4 · s · molecule-1 -Most of those less than photon-1) have not been put into practical use.

<Application to three-dimensional multilayer optical memory using two-photon absorption material>
Recently, networks such as the Internet and high-definition TV are rapidly spreading. In addition, HDTV (High Definition Television) will soon be broadcast, and there is an increasing demand for a large-capacity recording medium for easily and inexpensively recording image information of 50 GB or more, preferably 100 GB or more for consumer use. Furthermore, for business use such as computer backup use and broadcast backup use, an optical 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, the conventional two-dimensional optical recording medium such as DVD ± R is about 25 GB at most even if the recording / reproducing wavelength is shortened on the physical principle, and the recording is large enough to meet future requirements. It cannot be said that capacity can be expected.

  Under such circumstances, a three-dimensional optical recording medium has attracted attention as an ultimate high-density, high-capacity recording medium. Three-dimensional optical recording media can be recorded in dozens or hundreds of layers in the three-dimensional (film thickness) direction, resulting in tens or hundreds of times the ultra-high density and ultra-high capacity recording of conventional two-dimensional recording media. That is what we are trying to achieve. In order to provide a three-dimensional optical recording medium, it is necessary to be able to access and write at an arbitrary place in the three-dimensional (film thickness) direction. As a means for this, a method using a two-photon absorption material and holography (interference) There is a method of using. In a three-dimensional optical recording medium using a two-element absorbing material, so-called bit recording can be performed over tens or hundreds of times based on the physical principle described above, and higher density recording is possible, which is exactly the ultimate. It can be said that this is a high-density, high-capacity optical recording medium. As a three-dimensional optical recording medium using a two-photon absorbing material, a method of reading with fluorescence using a fluorescent substance for recording / reproduction (Lewitch, Eugene, Police et al., Japanese Translation of PCT International Publication No. 2001-524245 [Patent Document 1] Pavel, Eugen et al., Japanese translation of PCT publication No. 2000-512061 [Patent Document 2], and a method of reading with absorption or fluorescence using a photochromic compound (Korotif, Nikolai Eye et al., Japanese Patent Publication No. 2001-522119 [Patent Document 3]. ], Arsenov, U "Radimir et al., Japanese Patent Publication No. 2001-508221 [Patent Document 4]) have been proposed, but none of them presents a specific two-photon absorption material and is presented abstractly. An example of the two-photon absorption compound used is a two-photon absorption compound having extremely small two-photon absorption efficiency. Furthermore, since the photochromic compounds used in these patent documents are reversible materials, there are problems in non-destructive readout, 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 particular, in terms of non-destructive readout, long-term storage stability of recording, etc., it is preferable to reproduce by changing the reflectance (refractive index or absorption rate) or emission intensity using an irreversible material. There was no example that specifically disclosed the absorbent material.

  In addition, Kawada Jun, Kawada Yoshimasa, JP-A-6-28672 [Patent Document 5], Kawada Kei, Kawada Yoshimasa et al. And JP-A-6-118306 [Patent Document 6] are three-dimensional by refractive index modulation. However, there is no description of a method using a two-photon absorption three-dimensional optical recording material.

  As described above, the reaction is caused using the excitation energy obtained by non-resonant two-photon absorption, and as a result, the emission intensity when the laser focus (recording) part and the non-focus (non-recording) part are irradiated with light is determined. If modulation is possible with a method that cannot be rewritten, light emission intensity modulation can be generated at an arbitrary place in three-dimensional space with extremely high spatial resolution, and it can be applied to a three-dimensional optical recording medium that is considered to be the ultimate high-density recording medium. It becomes possible. Furthermore, since non-destructive readout is possible and the material is an irreversible material, it can be expected to have good storage stability and is practical.

  However, the currently available two-photon absorption compounds have a low two-photon absorption capability, so that a very high-power laser is required as a light source and a long recording time is required. Especially for use in three-dimensional optical recording media, construction of a two-photon absorption three-dimensional optical recording material that can perform recording with two-photon absorption with high sensitivity to achieve a fast transfer rate. Is essential. For that purpose, the difference between the two-photon absorption compound that can absorb two-photons with high efficiency and generate an excited state, and the two-photon absorption optical recording material using a two-photon absorption compound excited state in some way. Although a material containing a recording component that can efficiently form a thin film is effective, such a material has hardly been disclosed so far, and it has been desired to construct such a material.

  Therefore, conventionally, many proposals (for example, Japanese Patent Application Laid-Open No. 2005-213434 of Patent Document 7, Japanese Patent Application Laid-Open No. 2005-82507 of Patent Document 8, and Japanese Patent Application Laid-Open No. 2004-168690 of Patent Document 9 are related to the two-photon absorption material. In addition, we have already proposed many materials-related technologies (for example, Japanese Patent Application Laid-Open No. 2007-241168 in Patent Document 10, Japanese Patent Application Laid-Open No. 2007-241170 in Patent Document 11, and Patent Documents). 12 of JP-A-2007-246422, JP-A-2007-246463 of JP-A-2007-246463, JP-A-2007-246790 of JP-A-2007-246790, JP-A-2008-69294 of JP-A-2008-69294, and JP-A-2008-69294. Japanese Patent Laid-Open No. 2008-74708).

In addition, as a conventional example relating to a sensitization technique for a two-photon absorption material, we proposed that a physical sensitization mechanism using a surface plasmon enhancement field is imparted to a multiphoton absorption element (for example, Japanese Patent Application Laid-Open Publication No. 2006-2006). -330683).
Further, as conventional examples of the three-dimensional memory medium (material), those disclosed in Japanese Patent Application Laid-Open No. 2004-100606 of Patent Literature 18, those disclosed in Japanese Patent Application Publication No. 2005-517769, and Patent Literature 20 are disclosed. There exists a thing of Table 2004-534849 gazette.

Further, as a conventional example related to the light limiting element (material), there is one described in Japanese Patent Application Laid-Open No. 08-320422 of Patent Document 21, and as a conventional example related to the optical modeling technology, for example, Japanese Patent Application Laid-Open No. 2005-2005 No. 134783.
Further, examples of conventional (fluorescence) microscopes utilizing two-photon characteristics include those described in Japanese Patent Application Laid-Open No. 09-230246 of Patent Document 23, those described in Japanese Patent Application Laid-Open No. 10-142507, Patent Document 24, and Patent Documents. 25 are described in JP-A-2005-165212.

  In any of the conventional technical examples, there is no description about the two-photon absorption sensitization method in the application for the two-photon absorption material itself, and the technique described in Patent Document 17 is a physical enhancement using a plasmon field of metal fine particles. There is no description in the patent literature regarding chemical sensitization.

  The use of the two-photon absorption phenomenon enables various applications characterized by extremely high spatial resolution as described above. However, the two-photon absorption compounds currently available have a low two-photon absorption ability, so two-photon absorption is possible. As an excitation light source for inducing the light, an expensive and very high-power laser is required. Therefore, in order to realize a practical application using two-photon absorption using a small and inexpensive laser, it is essential to develop a high-efficiency two-photon absorption material. It is to provide a two-photon absorbing material.

  Another object of the present invention is to provide an electron-withdrawing compound having a high ionization potential and a pi-electron conjugated two-photon absorbing compound having an electron-donating group and capable of being chemically sensitized with the electron-withdrawing compound. Two-photon absorption light, which is recorded by recording in a non-rewritable manner using the two-photon absorption of the photon-absorbing material, and then reproducing by irradiating the recording material with light and detecting the difference in emission intensity It is an object of the present invention to provide a recording / reproducing method and a two-photon absorption optical recording material capable of such recording / reproducing.

  A further object of the present invention is to provide a two-photon absorption three-dimensional optical recording material, a two-photon absorption three-dimensional optical recording method and a reproducing method using them.

The present invention is solved by the following (1) to (18).
(1) A two-photon absorption material containing a two-photon absorption compound and an electron-withdrawing compound which are non-cyclic and comprise a pi-electron conjugated system in which at least one terminal is modified with an electron donating group.
(2) The two-photon absorption material according to item (1), wherein the ionization potential of the two-photon absorption compound is lower than the ionization potential of the electron-withdrawing compound.
(3) The two-photon absorbing compound has an (electron-donating group)-(pi-electron conjugated group) structure, or (electron-donating group)-(pi-electron conjugated group)-(electron-donating group) structure, or (electron-donating group) )-(Pi electron conjugated group)-(electron withdrawing group)-(pi electron conjugated group)-(electron donating group) structure material.
(4) The electron-withdrawing compound is cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester The two-photon absorption material as described in (1) above, which is either a compound part having an electron withdrawing group or an organic cation compound.
(5) The two-photon absorbing compound has an (electron donating group)-(pi electron conjugated group)-(electron donating group) structure or (electron donating group)-(pi electron conjugated group)-(electron withdrawing group)- (Pi-electron conjugated group)-(electron donating group) structure, wherein the electron donating group is any one of an alkoxy group, an alkylthio group, a dialkylamino group, and a diarylamino group. The two-photon absorption material according to item 1).
(6) The two-electron-withdrawing compound is any one of the compound having a nitro group, a compound having a cyano group, an aminium salt compound, and a pyridinium salt compound. Photon absorbing material.
(7) An optical recording material comprising the two-photon absorption material according to item (1).
(8) An optical limiting material comprising the two-photon absorption material according to item (1).
(9) An optical modeling material including the two-photon absorption material according to item (1).
(10) A two-photon excited fluorescent material comprising the two-photon absorbing material according to item (1).
(11) In a three-dimensional optical recording medium formed on a plane and capable of recording / reproducing on the plane and in a direction perpendicular to the plane, the two-photon absorption material described in (1) above is capable of optical recording. A three-dimensional optical recording medium characterized in that it is contained as at least a part of a recording layer to be performed.
(12) In the light limiting method including an element for limiting the light transmission light intensity of the signal light by the control light, the two-photon absorption material according to (1) is included as at least a part of the element. A light limiting method characterized by comprising:
(13) In the method of performing photo-molding by irradiating light to a photocurable resin, the two-photon absorption material according to (1) above is included as at least a part of the photocurable resin. Stereolithography method characterized by
(14) The analyte in the sample is selectively supported by the two-photon absorbing material described in the item (1), and the analyte is irradiated with light to emit the two-photon fluorescence light of the two-photon absorbing material. A two-photon excitation fluorescence detection method, characterized in that an analyte is detected by expression and detection.
(15) In the optical modeling apparatus that performs optical modeling by irradiating the laser beam condensed on the photocurable resin, the two-photon absorption material according to the item (1) is at least a part of the photocurable resin. An optical modeling apparatus characterized by being included as:
(16) In the light limiting device including an element that limits the light transmission light intensity of the signal light by the control light, the two-photon absorption material according to (1) is included as at least a part of the element. A light limiting device.
(17) In the light limiting device including an element that limits the path of the signal light by the control light, the two-photon absorption material described in the item (1) is included as at least a part of the element. A light limiting device.
(18) The analyte in the sample is selectively supported by the two-photon absorption material described in the item (1), and the analyte is irradiated with light to emit the two-photon fluorescence light of the two-photon absorption material. A two-photon excitation fluorescence detection apparatus that detects an analyte by expression and detection.

  According to the present invention, a two-photon-absorbing organic material that efficiently absorbs two-photons and realizes a change in spectrum, refractive index, or polarization state with high sensitivity, that is, an organic material having a large two-photon absorption cross section, particularly its chemical enhancement. The extremely excellent effect of providing a sensitive material is exhibited.

FIG. 2A is a schematic diagram of a recording / reproducing system for a three-dimensional multilayer optical memory. (B) It is a schematic sectional drawing of a recording medium. It is an example of the optical control element which optically switches the signal light of the wavelength which can carry out one photon excitation. It is an example of operation | movement of the light control element which carries out the all-optical switching excited by two photons. It is an example of the light control element which optically switches the optical path of output light. It is a figure which shows an optical modeling apparatus. It is an optical waveguide. It is a two-photon excitation fluorescence microscope. It is a figure which shows a measurement system outline. It is a graph which shows the waveform of the transmittance | permeability change. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a measurement result of a two-photon absorption cross section. It is a graph which shows the absorption spectrum of a film | membrane, and the fluorescence characteristic of a film | membrane.

  The two-photon absorption optical recording material of the present invention can be applied directly on the substrate by using a spin coater, roll coater or bar coater, or can be cast as a film and laminated on the substrate by a usual method. Thus, a two-photon absorption optical recording material can be obtained.

Here, “substrate” means any natural or synthetic support, preferably one that can exist in the form of a flexible or rigid film, sheet or plate.
Preferred examples of the substrate include polyethylene terephthalate, resin-primed polyethylene terephthalate, polyethylene terephthalate subjected to flame or electrostatic discharge treatment, cellulose acetate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, and glass. The substrate may be provided with a guide groove for tracking and address information in advance.

The solvent used can be removed by evaporation during drying. Heating or reduced pressure may be used for evaporation removal.
Furthermore, a protective layer (intermediate layer) for blocking oxygen and preventing interlayer crosstalk may be formed on the two-photon absorption optical recording material. 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. Further, an adhesive or a liquid substance may be present between the protective layer and the photosensitive film and / or between the base material and the photosensitive film in order to improve airtightness. Further, the protective layer (intermediate layer) between the photosensitive films may be provided with tracking guide grooves and address information in advance.

By focusing on an arbitrary layer of the above-described three-dimensional multilayer optical recording medium and performing recording and reproduction, it functions as the three-dimensional recording medium of the present invention. Further, even if the layers are not separated by a protective layer (intermediate layer), three-dimensional recording in the depth direction is possible from the two-photon absorption dye characteristics.
Hereinafter, preferred embodiments (specific examples) of the three-dimensional multilayer optical memory will be described. However, the present invention is not limited to these embodiments, and any structure capable of three-dimensional recording (recording in a plane and a film thickness direction) can be used. Any other structure may be used. A schematic diagram of a recording / reproducing system of a three-dimensional multilayer optical memory is shown in FIG. 1- (a), and a schematic sectional view of a recording medium is shown in FIG. 1- (b).

  In the recording medium (b) in the figure, a recording layer using the two-photon absorption compound of the present invention on a flat support (substrate 1) and an intermediate layer (protective layer) for preventing crosstalk are alternately 50 layers. Each layer is laminated, and each layer is formed by spin coating. The thickness of the recording layer is preferably 0.01 to 0.5 μm, and the thickness of the intermediate layer is preferably 0.1 μm to 5 μm. With this structure, the disk size is the same as the currently popular CD / DVD, and the terabyte class Can be realized. Further, a substrate 2 (protective layer) similar to the substrate 1 or a reflective layer made of a highly reflective material is formed by a data reproduction method (transmission / or reflection type).

  A single beam is used at the time of recording, and in this case, ultrashort pulse light of femtosecond order can be used. At the time of reproduction, it is also possible to use light having a wavelength different from that of the beam used for data recording or light of the same wavelength with low output. Recording and playback can be performed in either bit units or 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 a three-dimensional multilayer optical memory similarly formed according to the present invention may have a card shape, a plate shape, a tape shape, a drum shape, or the like.

<Application to optical limiting element using two-photon absorption material>
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, an electro-light control method using an electric signal has been conventionally employed. However, in the electro-optical control method, the processing speed (> 10 ps) is limited due to the band limitation due to the CR time constant as in the electric circuit, the response speed of the element itself, and the mismatch between the speed between the electric signal and the optical signal. In order to make full use of the broadband and high speed, which are the advantages of light, the light-light control technology for controlling the optical signal by the optical signal becomes very important. An optical element manufactured by processing the two-photon absorption material of the present invention as a response to this requirement,

  By utilizing optical changes such as transmittance, refractive index, absorption coefficient, etc. caused by irradiating light, the light intensity and frequency are directly modulated by light without using electronic circuit technology. It can be applied to high-speed optical switches in exchanges, optical computers, optical interconnections, and the like.

  The optical limiting element of the present invention that utilizes the change in optical characteristics due to two-photon absorption is an optically limiting element made of a normal semiconductor material, or an element with a much higher response speed (<1 ps) can be provided, and because of high sensitivity, an optical limiting element excellent in signal characteristics with a high S / N ratio can be provided.

(Examples of optical switches using single-photon absorption / supersaturated absorption and problems)
Available phenomena · SHB (spectrum hole burning)
・ Excitation and absorption ・ ISBT (transition between subbands)
・ QCSE (Quantum Confinement Shatalc effect)

Problems ・ It is difficult to obtain an ultra-high-speed response ・ Complex device fabrication (composition and structure) ・ Compatible wavelength range is often narrow → Wavelength selection system is narrow ・ Polarization dependence is large

(Advantages of an optical switch using two-photon absorption in the present invention)
Available phenomena ・ Advantages of nonlinearity of two-photon absorption ・ Super fast response in principle ・ Easy device fabrication (composition and structure) ・ Wide wavelength range → Wide wavelength selection ・ No polarization dependence

(Application example of changes in absorption characteristics)
FIG. 2 is an example of a light control element that optically switches a signal light having a wavelength that can be excited by one photon by exciting the two-photon absorbing material of the present invention with a control light having a wavelength that can be excited by two photons. . As an optical element, a form of a two-photon absorption material sandwiched between protective layers is shown, but this configuration does not limit the present invention.
The laser light incident from the control light and the signal light is condensed by the condensing device and is absorbed by the optical element only when the intensity of the control light is extremely strong, and the transmittance of the one-photon excitation wavelength changes. By utilizing the change in transmittance accompanying the nonlinearity of two-photon absorption, it becomes possible to switch the signal light with the intensity of the control light.

FIG. 3 shows an all-optical switching optical control element that excites the two-photon absorption material of the present invention by two-photon excitation using signal light having a wavelength (λ1) capable of two-photon excitation and control light having a wavelength (λ2) capable of two-photon excitation. It is an operation example.
Laser light that is control light and signal light is condensed by a condensing device onto a light limiting element having a two-photon absorption material as a main component. When the control light is off, signal light is output as it is, and control light is emitted. In the case of on, two-photons are absorbed together with the signal light, and the output is lost. By switching on / off the control light, an optical switch of signal light becomes possible.

(Application example of refractive index change)
FIG. 4 is an example of a light control element that optically switches the optical path of output light by two-photon excitation of the two-photon absorption material of the present invention with control light having a wavelength that can be two-photon excited.
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 two-photon absorption material 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, optical switching of the optical path of the optical waveguide becomes possible.

JP-A-8-320422 can be cited as a known document of this light limiting element. According to this, it is disclosed as an optical waveguide which forms a refractive index distribution by irradiating a light refractive index material whose refractive index changes with light irradiation with light having a wavelength whose refractive index changes. That is, a solid material dispersed in a material having a high two-photon absorption ability, a thin film, or a photocurable resin according to the present invention is arranged as an optical element, and is excited to an excited state by light of one wavelength (λ1). Further, by being excited from the state to another state with light of another wavelength (λ2), it becomes possible to design an optical waveguide using a refractive index change distribution according to the wavelength. Many of the two-photon absorption materials have fluorescence, and a fluorescent substance is arranged at one of the emission ends of the optical device or in the vicinity thereof, and excitation light (λ1) is emitted from the other, and excitation light and fluorescence ( A refractive index profile can also be formed by λ2). In this case, since the fluorescence is usually weaker than the excitation light, it is desirable to increase the sensitivity at the fluorescence wavelength.
Examples of the fluorescent substance include those obtained by dispersing a fluorescent dye in a photocurable substance or various resins.

<Application to stereolithography equipment using two-photon absorption material and stereolithography material>
The two-photon photocurable resin for stereolithography is a resin having a characteristic of causing a two-photon 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. Further, a reactive diluent is added to adjust the viscosity, curability and the like. When irradiated with light, the polymerization initiator or photosensitizing material absorbs two photons, 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 layered three-dimensional modeling, it is important that reactivity is good, deposition shrinkage during curing is small, and mechanical properties after curing are excellent.

  The two-photon absorption material of the present invention can be used as a two-photon absorption polymerization initiator or a two-photon absorption photosensitizing material that satisfies such requirements. Since the two-photon absorption material of the present invention has a higher two-photon absorption sensitivity than before, high-speed modeling is possible, and since the two-photon absorption phenomenon is used, a fine and three-dimensional modeling can be realized.

  In the present invention, the two-photon absorption material 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. The curing reaction is caused only in the vicinity of the focal point of the irradiation light to form an ultra-precise three-dimensional structure.

  FIG. 5 is an example of an optical modeling apparatus when performing optical modeling using the two-photon absorption material of the present invention. When the pulsed laser light from the light source (21) is condensed on the two-photon absorption material (24) of the present invention through the movable mirror (22) and the condenser lens (23), the photon density is only in the vicinity of the condensing point. A high region 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) (galvano mirror and Z stage). The resin can be locally cured with order accuracy, and a desired three-dimensional workpiece can be easily formed.

  Moreover, an optical waveguide is shown in FIG. 6 as an example of the modeled object thus manufactured. 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 of different wavelengths. In 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. An optical waveguide structure using such a refractive index change due to wavelength uses the optical modeling apparatus shown in FIG. 2, and a thin film containing the two-photon absorption material of the present invention or the two-photon absorption material of the present invention is used as a photocurable resin. It can be formed by stereolithography of a solid object dispersed in the same.

  A publicly known technique relating to a method for producing a molded article that can be used in the present invention includes that described in JP-A-2005-134873. According to this, pulsed laser light is subjected to interference exposure on the surface of the photosensitive polymer film without using a mask. The laser beam consists of light having a wavelength component that exerts the photosensitive function of the photosensitive polymer film, and is selected according to the type of photosensitive polymer or the group or site having the photosensitive function of the photosensitive polymer. Has been.

Also, as a known technique related to the optical waveguide, there are an optical waveguide formed by irradiating light to a photorefractive index material described in JP-A-08-320422, JP-A-2004-277416, and JP-A-11-167036. The thing currently disclosed by gazette, Unexamined-Japanese-Patent No. 2005-257741, etc. is mentioned.
Compared with the prior art, the features of the optically shaped object using the two-photon absorption material of the present invention are as follows. That is,
i) Processing resolution beyond the diffraction limit Due to the nonlinearity of the two-photon absorption with respect to the light intensity, the photocurable 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 Since the two-photon absorption sensitivity of the modeled object processed using the two-photon absorption material of the present invention is higher than the conventional one, the beam scanning speed can be increased.
iii) The three-dimensional processable photocurable resin is transparent to near-infrared light that induces two-photon absorption. Therefore, even when the focused light is condensed deeply into the resin, internal curing is possible. In the conventional SIH, when the beam is condensed deeply, the light intensity at the condensing point is reduced by light absorption, and the internal curing becomes difficult. In the present invention, 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 this method, such a problem is solved because modeling is performed inside the resin.
v) Application to mass production: By using ultra-high speed modeling, it is possible to manufacture a large number of parts or movable mechanisms continuously in a short time.

(Two-photon excitation fluorescence detection method using two-photon absorption material, application to equipment)
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 of FIG. 7 generates laser light from a light source (51) that generates sub-picosecond monochromatic coherent pulses in the near-infrared region, passes through a dichroic mirror (52), and is collected by a condenser (53). Two-photon fluorescence is generated by focusing in the sample (54) containing the analyte to which the two-photon absorbing material of the present invention is bound. A three-dimensional fluorescence image is obtained by manipulating laser light on a sample, detecting the fluorescence intensity at each location with a photodetector (56), and plotting the fluorescence intensity and the obtained position information on a computer. Can do. 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 (55) may be moved, or a movable mirror ( The laser beam may be scanned using a galvanometer mirror or the like.

  A two-photon excitation fluorescence microscope having such a configuration can obtain a high-resolution image in the optical axis direction. However, by using a confocal pinhole plate, the resolution can be further improved in both the in-plane and optical axis directions. it can.

  The two-photon fluorescent material used in this way can be used by staining an analyte or by dispersing it 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.

  Japanese Laid-Open Patent Publication No. 9-230246 is a well-known document of a two-photon excitation fluorescence microscope. 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 multiphoton absorption. With such a configuration, it is possible to obtain high resolution in the optical axis direction by utilizing the nonlinear effect of multiphoton 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. Such a two-photon optical element uses, as the optical element, a solid material dispersed in a material having a high two-photon absorption ability, a thin film, or a photocurable resin of the present invention, just like the above-described light control element. Is possible.

  The two-photon absorption material of the present invention can be applied to a device for detecting two-photon excitation fluorescence such as a two-photon excitation laser scanning microscope. Moreover, since it has a larger two-photon absorption cross-sectional area than conventional two-photon excitation fluorescent materials, it exhibits high two-photon absorption (emission) characteristics at a low concentration. Therefore, according to the present invention, not only a highly sensitive two-photon absorption material can be obtained, but there is no need to increase the intensity of light applied to the material, and deterioration and destruction of the material can be suppressed. The adverse effect on the properties of other components can also be reduced. Similarly, even when applied to a living body, since the intensity of light to be irradiated can be lowered, damage to the living body can be reduced.

(Photodynamic therapy)
Photodynamic therapy (PDT) is a treatment that has already been clinically applied to some early malignant tumors in human medicine.

  A photosensitive substance (two-photon absorbing material) is taken into tumor cells and endothelial cells of new blood vessels in the tumor tissue, and active oxygen is generated by irradiating the affected area with laser light. This active oxygen is thought to cause tumor cells and tissues to be damaged and the tumor to disappear. PDT is a treatment method that uses this photodynamic reaction, and PDT uses a photosensitizer and low-power laser light that are low in toxicity, and is characterized by a low burden on the living body. In addition, when the photosensitive substance is a two-photon absorption material and the wavelength of light used is a long wavelength that can be transmitted through the living body, the burden on the living body is further reduced. As a treatment method, image diagnosis of the tumor is performed, and the position and size of the tumor are confirmed. In order to irradiate the entire tumor with laser light, a fiber is placed on the tumor based on the CT image, and laser light is irradiated.

  In surgical therapy, the body is incised and the tumor is removed by surgery, so the function and form of the body may be impaired. In the case of PDT, there is an advantage that normal tissue can be preserved as much as possible. .

  The two-photon absorption material of the present invention can be applied to various devices by itself or in a thin film mixed with various resins, or in bulk.

  For example, in an optical disc, the thin film is in contact with a substrate, and the substrate material is polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyester, polyvinyl alcohol, glass or the like. In the case of stacking, the surface of the thin film is in contact with the intermediate layer (partition layer). Specific examples of the intermediate layer include polyolefins such as polypropylene and polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, plastic films such as polyethylene terephthalate or cellophane film, and various photo-curing resins.

Next, even when applied to various optical devices and optical modeling devices, they are mixed with various resins or mixed with a photocurable resin.
Accordingly, the use requirement of the two-photon absorption material of the present invention is that the material is mixed with various resins or glass, or the interface of the two-photon absorption material layer is in contact with various resins or glass.

In other words, the two-photon absorption material of the present invention is in contact with various resins or glass at the micro level or the macro level.
The two-photon absorption material of the present invention will be described.
The two-photon absorption material of the present invention includes: 1) a two-photon absorption compound comprising a pi-electron conjugated system in which at least one terminal is modified with an electron donating group; and 2) an ionization potential is larger than that of the two-photon absorption compound. It comprises at least both of the electron-withdrawing compound.

  The two-photon absorption compound has an (electron donating group)-(pi electron conjugated group) structure, or (electron donating group)-(pi electron conjugated group)-(electron donating group) structure, or (electron donating group)-( Any one of the structures of pi electron conjugated group- (electron withdrawing group)-(pi electron conjugated group)-(electron donating group) is preferable, and the sensitizing effect increases as the electron donating property increases. Group)-(pi electron conjugated group)-(electron donating group) structure or (electron donating group)-(pi electron conjugated group)-(electron withdrawing group)-(pi electron conjugated group)-(electron donating group) structure More preferably, the electron donor group is any one of an alkoxy group, an alkylthio group, a dialkylamino group, and a diarylamino group.

  The sensitization phenomenon of the present invention is obtained by electronic interaction between the electron donating group part of the two-photon absorption compound and the electron withdrawing part of the electron-withdrawing compound, and the both electronic states that can obtain a larger interaction are obtained. It is preferable that the ion-withdrawing compound is larger in ionization potential than the two-photon absorption compound.

  The electron withdrawing compound includes cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group, etc. Either a compound having an electron-withdrawing group or an organic cation compound is preferable, and the greater the electron-withdrawing property, the greater the sensitizing effect. Therefore, a compound having a nitro group, a compound having a cyano group, an aminium salt compound, and pyridinium More preferably, it is any of salt compounds.

  Examples of typical two-photon absorption compounds applicable to the present invention include the following.

In the formula, X1 and X2 each independently represents an aryl group or heterocyclic group, at least one of which is substituted with an electron donating group, and Y represents an atomic group containing an oxygen atom, a sulfur atom, a cyano group or a carboxyl group.
In the formula, R1 and R5 are hydrogen or a methylene group, and the methylene groups are bonded to each other to form a ring. R2 to R4 and R6 to R8 each represent a hydrogen atom or a substituent, and some of R1 to R4 and R5 to R8 may be bonded to each other to form a ring, and n and m are 2 or more. May be the same or different.
m and n represent an integer of 0 to 2.

In the formula, Z1 and Z2 each independently represent an atomic group forming a 5- or 6-membered ring, at least one of which is substituted with an electron donating group, and Y includes an oxygen atom, a sulfur atom, a cyano group, or a carboxyl group Represents an atomic group. In the formula, R ₁ and R ₆ are hydrogen or a methylene group, and the methylene groups are bonded to each other to form a ring. _{R 2 ~R 5, R 7 ~R} 10 each represent a hydrogen atom or a _substituent, may form a ring number is bound to each other of R 1 to R ₅ and _R 7 _{to R 10,} When n and m are 2 or more, they may be the same or different. R ₁₁ and R ₁₂ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and m and n each represents an integer of 0 to 2.

In the general formula, X represents an atomic group that forms a 5- or 6-membered nitrogen-containing heterocyclic ring, Y represents an atomic group that forms a 5-membered or 6-membered ring, and Z represents an alkyl group, an alkenyl group, or an aryl group. Or a heterocyclic group.
R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom or a substituent, and some of R ₁ , R ₂ , R ₃ and R ₄ are bonded to each other to form a ring. May be. n and m each independently represent a 1-4 integer, if n and m is 2 or more, plural _{R 1,} R 2, _{R 3} and _{R 4} may be the same or different.

In the formula, R _{1 to} R ₈ are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms, and R ₉ and R ₁₀ are the same or Differently, it represents a pyridyl group, and n represents an integer of 1 to 4.

In the formula, X ₁ and X ₂ each independently represent an aryl group or heterocyclic group, at least one of which is substituted with an electron donating group, R _{1 to} R ₄ each represents a hydrogen atom or a substituent, and R ₁ to Some of R ₄ may be bonded to each other to form a ring. When n and m are 2 or more, a plurality of R _{1 to} R ₄ may be the same or different, and n and m are each The integer of 1-4 is represented.

In the formula, X ₁ and X ₂ each independently represent an aryl group or heterocyclic group, at least one of which is substituted with an electron donating group, R _{1 to} R ₄ each represents a hydrogen atom or a substituent, and R ₁ to Some of R ₄ may be bonded to each other to form a ring. When n and m are 2 or more, a plurality of R _{1 to} R ₄ may be the same or different, and n and m are each The integer of 1-4 is represented.

In the formula, Ar represents a substituted or unsubstituted divalent group of thiophene, biphenyl, fluorene or anthracene, and X ₁ and X ₂ each independently represents an aryl group or a heterocyclic ring, at least one of which is substituted with an electron donating group represents a group, R ₁ to R ₄ each represent a hydrogen atom or a substituent, they may form a ring some of R ₁ to R ₄ each other, if n and m are 2 or more The plurality of R _{1 to} R ₄ may be the same or different, and n and m each represent an integer of 1 to 4.

  A two-photon absorption material having a repeating unit represented by the following general formula.

In the formula, Ar is a substituted or unsubstituted divalent group selected from bithiophene, triphenylamine, fluorene, naphthalene, anthracene, and benzothiadiazole, R ₁ is independently a hydrogen atom, a substituted or unsubstituted alkyl group, A substituted or unsubstituted phenyl group.

  A two-photon absorption material having a repeating unit represented by the following general formula.

In the formula, Ar ₁ is a divalent group of an aromatic hydrocarbon group or a heterocyclic group which may have a substituent, and Ar ₂ is a divalent group of an aromatic hydrocarbon group or a heterocyclic group which may have a substituent. Represents a valent group or a single bond, and m represents 0 or 1.

In the formula, Ar ₁ , Ar ₃ and Ar ₄ represent a divalent group of a substituted or unsubstituted aromatic hydrocarbon group, Ar ₂ represents a substituted or unsubstituted aromatic hydrocarbon group, and R ₁ and R ₂ Each independently represents a group selected from a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, or a substituted or unsubstituted alkylthio group. m and n are each independently an integer of 0 to 2, and n is 0 or 1.

In the formula, R ₁ and R ₅ are hydrogen or a methylene group, and the methylene groups are bonded to each other to form a ring. R _{2 to} R ₄ and R _{6 to} R ₈ each represent a hydrogen atom or a substituent, and some of R _{1 to} R ₄ and R _{6 to} R ₈ may be bonded to each other to form a ring; When n and m are 2 or more, they may be the same or different. X ₁ , X ₂ and Y represent a hydrogen atom, an alkyl group, an alkoxy group, an amino group, a dialkylamino group and a diarylamino group, at least one of X ₁ and X ₂ represents an electron donating group, and m and n are Represents an integer from 0 to 2.
The electron donating group as used in the present invention refers to a substituent having the effect of increasing the electron density as compared with a carbon atom at a specific position of a molecule as an electron donating group. Examples thereof include an unsubstituted alkoxy group, an alkylthio group, an amino group, an alkylamino group, a dialkylamino group, an arylamino group, and a diarylamino group.

  Examples of typical electron-withdrawing compounds applicable to the present invention include the following.

In the formula, R ₁ and R ₂ are cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group R ₃ and R ₄ each independently represent a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, Represents a substituted or unsubstituted amino group.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl , Formyl, sulfonyl, nitro, ester group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted amino group R ₅ and R ₆ represent a cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group. Represent.

In which R ₁ , R ₂ , R ₃ , R ₄ are cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, Represents a sulfonyl, nitro, ester or amino group, and R ₃ represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.

In which R ₁ , R ₂ , R ₃ , R ₄ are cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, Represents a sulfonyl, nitro or ester group.

In which R ₁ and R ₂ are cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group R ₃ and R ₄ each independently represent a hydrogen atom, a halogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, Represents a substituted or unsubstituted amino group.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are a hydrogen atom, cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl , Formyl, sulfonyl, nitro, ester group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted amino group Represent.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, L represents a binary linking group, and X represents a counter ion. Represents.

Wherein R ₁ , R ₂ , R ₃ , R ₄ are a hydrogen atom, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl , Sulfonyl, nitro, ester group, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylthio group, substituted or unsubstituted amino group, X represents a counter ion.
Y is any of —O—, —S—, —CR ₅ R ₆ —, —NR ₇ —, wherein R ₅ , R ₆ , and R ₇ are substituted or unsubstituted alkyl groups, substituted or unsubstituted aryls. Represents a group.

In the formula, R ₁ , R ₂ , and R ₃ represent a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aryl group, and R ₄ , R ₅ , R ₆ , and R ₇ are a hydrogen atom, halogen, Mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group, substituted or unsubstituted alkyl group, substituted or unsubstituted An aryl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted amino group, L represents a binary linking group, and X represents a counter ion.

Examples of the unsubstituted alkyl group and the alkyl group in the unsubstituted alkoxy group include a linear or branched alkyl group. The substituted alkyl group and the substituted alkyl group in the substituted alkoxy group include 2 -Hydroxy-substituted alkyl groups such as hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group and 2-hydroxypropyl group; carboxy-substituted alkyl groups such as carboxymethyl group, 2-carboxyethyl group and 3-carboxypropyl group Cyano-substituted alkyl groups such as 2-cyanoethyl group and cyanomethyl group; amino-substituted alkyl groups such as 2-aminoethyl group; 2-chloroethyl group, 3-chloropropyl group, 2-chloropropyl group, 2,2,2- Halogen atom-substituted alkyl groups such as trifluoroethyl group; benzyl group, p-chloro Phenyl-substituted alkyl groups such as benzyl group and 2-phenylethyl group; 2-methoxyethyl group, 2-ethoxyethyl group, 2- (n) propoxyethyl group, 2- (iso) propoxyethyl group, 2- (n) Alkoxy-substituted alkyl groups such as butoxyethyl group, 2- (iso) butoxyethyl group, 2- (2-ethylhexyloxy) ethyl group, 3-methoxypropyl group, 4-methoxybutyl group, 2-methoxypropyl group; (2-methoxyethoxy) ethyl group, 2- (2-ethoxyethoxy) ethyl group, 2- (2- (n) propoxyethoxy) ethyl group, 2- (2- (iso) propoxyethoxy) ethyl group, 2- (2- (n) butoxyethoxy) ethyl group, 2- (2- (iso) butoxyethoxy) ethyl group, 2- {2- (2-ethylhexyl) Xoxy) alkoxyalkoxy-substituted alkyl groups such as ethoxy} ethyl group; substituted alkyl groups such as allyloxyethyl group, 2-phenoxyethyl group, 2-benzyloxyethyl group; 2-acetyloxyethyl group, 2-propionyloxyethyl group , 2- (n) butyryloxyethyl group, 2- (iso) butyryloxyethyl group, 2-trifluoroacetyloxyethyl group and other acyloxy-substituted alkyl groups; methoxycarbonylmethyl group, ethoxycarbonylmethyl group, (n ) Propoxycarbonylmethyl group, (iso) propoxycarbonylmethyl group, (n) butoxycarbonylmethyl group, (iso) butoxycarbonylmethyl group, 2-ethylhexyloxycarbonylmethyl group, benzyloxycarbonylmethyl group, furfuryloxycarbonyl Methyl group, tetrahydrofurfuryloxycarbonylmethyl group, 2-methoxycarbonylethyl group, 2-ethoxycarbonylethyl group, 2- (n) propoxycarbonylethyl group, 2- (iso) propoxycarbonylethyl group, 2- (n) Substituted or unsubstituted butoxycarbonylethyl group, 2- (iso) butoxycarbonylethyl group, 2- (2-ethylhexyloxycarbonyl) ethyl group, 2-benzyloxycarbonylethyl group, 2-furfuryloxycarbonylethyl group, etc. Alkoxycarbonyl-substituted alkyl group; 2-methoxycarbonyloxyethyl group, 2-ethoxycarbonyloxyethyl group, 2- (n) propoxycarbonyloxyethyl group, 2- (iso) propoxycarbonyloxyethyl group, 2- (n) butoxyca Substitution of bonyloxyethyl group, 2- (iso) butoxycarbonyloxyethyl group, 2- (2-ethylhexyloxycarbonyloxy) ethyl group, 2-benzyloxycarbonyloxyethyl group, 2-furfuryloxycarbonyloxyethyl group, etc. Or an unsubstituted alkoxycarbonyloxy-substituted alkyl group; a heterocyclic-substituted alkyl group such as a furfuryl group or a tetrahydrofurfuryl group;
Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group.

Specific examples of the alkyl group in the alkyl group and the alkoxy group include the following. In addition, these alkyl groups may be substituted with a substituent such as a halogen atom. Methyl group, ethyl group, n-propyl group, n-butyl group, isobutyl group, n-pentyl group, neopentyl group, isoamyl group, 2-methylbutyl group, n-hexyl group, 2-methylpentyl group, 3-methylpentyl Group, 4-methylpentyl group, 2-ethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2-ethylpentyl group, 3- Ethylpentyl group, n-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3-ethylhexyl group, n-nonyl group, n- Primary alkyl group such as decyl group, n-dodecyl group; isopropyl group, sec-butyl group, 1-ethylpropyl group, 1-methylbutyl group, , 2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1-ethyl-2-methylpropyl group, 1-methylhexyl group, 1-ethylheptyl group, 1-propylbutyl group, 1-isopropyl-2-methylpropyl group, 1-ethyl-2-methylbutyl group, 1-propyl-2-methylpropyl group, 1-methylheptyl group, 1-ethylhexyl Group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethylheptyl group, 1-propylhexyl group Secondary alkyl groups such as 1-isobutyl-3-methylbutyl group; tert-butyl group, tert-hexyl group, Tertiary alkyl groups such as ert-amyl group and tert-octyl group; cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cyclohexyl group, bornyl And cycloalkyl groups such as an isobornyl group and an adamantane group.
The aryl group includes phenyl, methylphenyl, dimethylphenyl, trimethylphenyl, ethylphenyl, tert-butylphenyl, di (tert-butyl) phenyl, butylphenyl, methoxyphenyl, and dimethoxy. Examples thereof include a phenyl group, a trimethoxyphenyl group, and a butoxyphenyl group, and these aryl groups may be substituted with a substituent such as halogen.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples unless it exceeds the gist.

A THF solution of the following two-photon absorption compound (Chemical Formula 1) and the electron-withdrawing compound (Chemical Formula 2) was prepared. Each solution is mixed at a ratio of 10/0, 8/2, 6/4, 4/6, 2/8, 0/10 (the total number of molecules in the solution is constant), and the following two-photon absorption cross section The two-photon absorption cross section was measured by the evaluation method. The waveform of the transmittance change in the Z-scan measurement method is shown in FIG. 9, the measurement result of the two-photon absorption cross section is shown in FIG. 10, and the sensitization coefficient is shown in (Table 1).
The sensitization coefficient is obtained by dividing the two-photon absorption cross section obtained most in the mixed system of the two-photon absorption compound and the electron-withdrawing compound by the two-photon absorption cross-section of the two-photon absorption compound alone. If it is above, it shows that the sensitization effect was acquired.

(Example 2) to (Example 4)
In Example 1, instead of the electron-withdrawing compound (A-1), (A-2), (A-3), and (A-4) were used, and the same evaluation as in Example 1 was performed. The measurement results of the two-photon absorption cross section are shown in FIG. 11, FIG. 12, and FIG. 13, and the sensitization coefficients are shown in (Table 1).

(Example 5) to (Example 7)
In Example 1,

  Instead of the two-photon absorption compound of (Chemical T-1), (Chemical T-2), (Chemical T-3), and (Chemical T-4) were used, and the same evaluation as in Example 1 was performed. The measurement results of the two-photon absorption cross section are shown in FIGS. 14, 15, and 16, and the sensitization coefficients are shown in (Table 1).

(Example 8) to (Example 12)
In Example 1, instead of the electron-withdrawing compound of (Chemical A-1), (Chemical A-5), (Chemical A-6), (Chemical A-7), (Chemical A-8), ( The same evaluation as in Example 1 was performed. The sensitization coefficient is shown in (Table 1).

(Example 13 to Example 19)
In Example 1, instead of the two-photon absorption compound of (Chemical T-1), (Chemical T-5), (Chemical T-6), (Chemical T-7), (Chemical T-8), ( Evaluation was made in the same manner as in Example 1 with Chemical Formula T-9), Chemical Formula T-10, and Chemical Formula T-11. The sensitization coefficient is shown in (Table 1).

(Comparative Examples 1-3)
In Example 1, instead of the two-photon absorption compound of (Chemical T-1), an electron donating compound (Chemical T-12) was used, and the same evaluation as in Example 1 was performed. The sensitization coefficient is shown in (Table 1).

(Comparative Example 4)
In Example 1, instead of the electron-withdrawing compound of (Chemical A-1), the electron-donating compounds (Chemical D-1), (Chemical D-2), and the two-photon absorbing compound (Chemical T-2), respectively. And the same evaluation as in Example 1. The measurement results of the two-photon absorption cross section are shown in FIGS. 17, 18 and 19, and the sensitization coefficients are shown in (Table 1).

(Evaluation results)

  In order to investigate the interaction between the two-photon absorption compound (Chemical T-1) and the electron-withdrawing compound (Chemical A-6), which obtained a large sensitization efficiency as a result, the two-photon absorption compound (Chemical T-1) alone was used. And the absorption spectrum of the mixed system (100/25 mol ratio) of the mixed system (100/25 mol ratio) of the two-photon absorption compound (Chemical T-1) and the electron withdrawing compound (Chemical A-6) and the fluorescence characteristics of the film, respectively, FIG. The results are shown in (Table 2).

図２０と表２の結果から、二光子吸収化合物（化Ｔ−１）と電子吸引性化合物（化Ａ−６）の混合系では、二光子吸収化合物（化Ｔ−１）から電子吸引性化合物（化Ａ−６）への電荷移動相互作用が生じていると考えられ、それが二光子吸収の増感現象を引き起こしていると想定できる。
二光子吸収化合物から電子吸引性化合物へ電子を与える場合、電子移動が効率良く起こるためには、二光子吸収化合物のイオン化ポテンシャルが、該電子吸引性化合物のイオン化ポテンシャルより低いことが好ましい。

From the results of FIG. 20 and Table 2, in the mixed system of the two-photon absorption compound (Chemical T-1) and the electron withdrawing compound (Chemical A-6), the two-photon absorption compound (Chemical T-1) to the electron withdrawing compound It is considered that a charge transfer interaction with (Chemical A-6) occurs, and it can be assumed that this causes a sensitization phenomenon of two-photon absorption.
When electrons are supplied from the two-photon absorption compound to the electron-withdrawing compound, the ionization potential of the two-photon absorption compound is preferably lower than the ionization potential of the electron-withdrawing compound in order for electron transfer to occur efficiently.

  Table 3 shows the results of ionization potentials measured by photoelectron spectroscopy (RIKEN Keiki: AC-2) of typical two-photon absorption compounds, electron-withdrawing compounds, and electron-donating compounds used in the examples. The above relationship is satisfied in a system in which the sensitization phenomenon of two-photon absorption can be obtained efficiently.

(2) The two-photon absorption ability is sensitized by the coexistence of a two-photon absorption compound consisting of a pi-electron conjugated system which is acyclic and at least one of its ends is modified with an electron donating group.
■ Due to the charge transfer interaction from the two-photon absorption compound to the electron-withdrawing compound, the ionization potential of the two-photon absorption compound is lower than the ionization potential of the electron-withdrawing compound in order for charge transfer to occur efficiently. It is preferable.
(1) From the results of Examples 18 and 19 and Example 17 and Comparative Example 4, (electron donating group)-(pi electron conjugated group)-(electron donating group) structure or (electron donating group)-(pi electron conjugated group) )-(Electron withdrawing group)-(pi electron.

[Evaluation method of two-photon absorption cross section]
A schematic diagram of the measurement system is shown in FIG.
Measurement light source: femtosecond titanium sapphire laser wavelength: 720-920 nm
Pulse width: 100 fs
Repeat: 80MHz
Optical power: 800mW
Measurement method: Z-scan method Light source wavelength: 780 to 900 nm
Cuvette inner diameter: 1mm
Measurement optical power: about 500mW
Repetition frequency: 80 MHz
Condenser lens: f = 75 mm
Condensing diameter: ~ 40 μm

A quartz cell filled with the sample solution was placed in the collected optical path portion, and Z-scan measurement was performed by moving the position along the optical path.
The transmittance was measured, and the nonlinear absorption coefficient was determined from the result by the theoretical formula (I).

(In the above formula, T represents transmittance (%), I 0 represents excitation light density [GW / cm ² ], L 0 represents sample cell length [cm], and β represents nonlinear absorption coefficient [cm / GW].)

From this nonlinear absorption coefficient, a two-photon absorption cross-sectional area σ2 was determined by the following formula (II).
(The unit of σ2 is 1GM = 1 × 10 ⁻⁵⁰ cm ⁴ · s · photon−1.)

(In the formula, h is Planck's constant [J · s], ν is the frequency of the incident laser light ^[s -1], _{N A} is Avogadro's number, C is concentration of solution [mol / L].)

(About Figure 5)
21 Light source 22 Movable mirror 23 Condensing lens 24 Two-photon absorption material 25 Movable stage (about FIG. 7)
51 Light Source 52 Dichroic Mirror 53 Condensing Device 54 Sample 55 Movable or Fixed Stage 56 Photodetector

JP-T-2001-524245 Special table 2000-512061 gazette JP-T-2001-522119 Special table 2001-508221 gazette JP-A-6-28672 JP-A-6-118306 JP-A-2005-213434 JP 2005-82507 A JP 2004-168690 A JP2007-241168A JP2007-241170 JP2007-246422A JP 2007-246463 A JP2007-246790 JP 2008-69294 A JP2008-74708 JP 2006-330683 A JP2004-100606 Special table 2005-517769 Special table 2004-534849 JP 08-320422 A JP-A-2005-134783 JP 09-230246 A JP-A-10-142507 JP 2005-165212 A Jean-Luc Bredas et al Science, 281,1653 (1998)

Claims (18)

  A two-photon absorbing material comprising a two-photon absorbing compound which is non-cyclic and comprises a pi-electron conjugated system in which at least one terminal is modified with an electron donating group and an electron-withdrawing compound.   The two-photon absorption material according to claim 1, wherein an ionization potential of the two-photon absorption compound is lower than an ionization potential of the electron-withdrawing compound.   The two-photon absorption compound has an (electron donating group)-(pi electron conjugated group) structure, or (electron donating group)-(pi electron conjugated group)-(electron donating group) structure, or (electron donating group)-( 2. The two-photon absorbing material according to claim 1, wherein the two-photon absorbing material has a structure of pi electron conjugated group- (electron withdrawing group)-(pi electron conjugated group)-(electron donating group).   The electron withdrawing compound is an electron of cyano, halogen, mono-, di- or tri-halogenated alkyl, amide, N- (mono or dialkyl) aminocarbonyl, alkoxycarbonyl, carboxyl, formyl, sulfonyl, nitro, ester group The two-photon absorption material according to claim 1, wherein the two-photon absorption material is a compound part having an attractive group or an organic cation compound.   The two-photon absorption compound has an (electron donating group)-(pi electron conjugated group)-(electron donating group) structure or (electron donating group)-(pi electron conjugated group)-(electron withdrawing group)-(pi electron 2. The conjugated group)-(electron donating group) structure, wherein the electron donating group is an alkoxy group, an alkylthio group, a dialkylamino group, or a diarylamino group. Photon absorbing material.   The two-photon absorbing material according to claim 1, wherein the two-electron withdrawing compound is any one of a compound having a nitro group, a compound having a cyano group, an aminium salt compound, and a pyridinium salt compound.   An optical recording material comprising the two-photon absorption material according to claim 1.   A light limiting material comprising the two-photon absorbing material according to claim 1.   An optical modeling material comprising the two-photon absorption material according to claim 1.   A two-photon excited fluorescent material comprising the two-photon absorbing material according to claim 1.   In the three-dimensional optical recording medium formed on a plane and capable of recording / reproducing on the plane and in a direction perpendicular to the plane, the two-photon absorption material according to claim 1 includes at least a recording layer on which optical recording is performed. A three-dimensional optical recording medium characterized by being included as a part.   In the light limiting method provided with the element which restricts the light transmission light intensity of signal light with control light, the two-photon absorption material according to claim 1 is included as at least a part of the element. Light limiting method.   In the method of performing optical modeling by irradiating light to a photocurable resin, the two-photon absorbing material according to claim 1 is included as at least a part of the photocurable resin. Method.   By selectively carrying the two-photon absorption material according to claim 1 on an analyte in a sample, and irradiating the analyte with light to express and detect the two-photon fluorescence light of the two-photon absorption material A two-photon excitation fluorescence detection method for detecting an analyte.   In the optical modeling apparatus which performs optical modeling by irradiating the laser beam condensed on the photocurable resin, the two-photon absorption material according to claim 1 is included as at least a part of the photocurable resin. Stereolithography apparatus characterized by   2. An optical limiting device comprising an element that limits the intensity of transmitted light of signal light with control light, wherein the two-photon absorption material according to claim 1 is included as at least a part of the element. Light limiting device.   A light limiting device comprising an element for limiting the path of signal light by control light, wherein the two-photon absorption material according to claim 1 is included as at least a part of the element. Restriction device.   By selectively carrying the two-photon absorption material according to claim 1 on an analyte in a sample, and irradiating the analyte with light to express and detect the two-photon fluorescence light of the two-photon absorption material A two-photon excitation fluorescence detection apparatus for detecting an analyte.

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