JP2004184933A - Grating, lens array, fresnel lens, photonic crystal, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of easily making a polymeric material superior in flexibility into a grating, a lens array, a Fresnel lens, or photonic crystal. <P>SOLUTION: Pulse laser having a high peak output value is radiated to the polymeric material to form a refractive index changed portion in the polymeric material, and preferably, ≤9dB/cm light loss for a wavelength of 600 to 1600nm is given to the polymeric material to obtain a grating, a lens array, or photonic crystal. Thus the polymeric material is made into the grating or the like. A flexible optical waveguide can be obtained because the grating or the like is easily formed without passing a complicated process and uses the polymeric material. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grating, a lens array, a Fresnel lens or a photonic crystal in which a refractive index change is formed in a polymer material by laser irradiation, and a method of manufacturing the same.
[0002]
[Prior art]
Gratings, lens arrays, Fresnel lenses or photonic crystals are becoming increasingly important as optical components. For example, in the case of a grating, it is used for a wavelength filter or the like in optical communication, and is also used for a pickup or the like in a CD optical system. Lens arrays are also used for various purposes such as liquid crystal projectors. In addition, photonic crystals, which are artificial structures in which different refractive index media are arranged in a multidimensional manner, can control the propagation of light to a high degree, making them suitable for next-generation optical devices such as microminiature optical integrated circuits. Applications are expected.
[0003]
However, all of them have a problem in terms of a complicated manufacturing method and yield.
[0004]
On the other hand, various methods for producing a grating on a glass material by ultrashort pulse laser beam processing such as a femtosecond laser have been attempted. (For example, Patent Documents 1, 2, and 3). However, glass materials have incompatible applications, such as cracking of components and lack of flexibility.
[0005]
On the other hand, a method for producing an optical waveguide by processing a polymer with ultrashort pulse laser light is disclosed (Patent Document 4), but no reference is made to a grating, a lens array, a Fresnel lens, or a photonic crystal.
[0006]
Also disclosed is a method of producing, for example, a grating by introducing or mixing a structure of azobenzene, stilbene, or the like that changes the refractive index by irradiation of light with a polymer. (Patent Document 5) In this method, the resin system is limited, and there is no general versatility or lacks stability.
[0007]
On the other hand, when an excimer laser or the like is applied to a polymer, a processing method called ablation by decomposing and removing the polymer is disclosed (Patent Document 6). In this processing method, a grating or the like is changed by changing the refractive index. It is difficult to make.
[0008]
[Patent Document 1]
JP 2000-56112
[0009]
[Patent Document 2]
JP-A-2001-324634
[0010]
[Patent Document 3]
JP-A-2001-276985
[0011]
[Patent Document 4]
JP-A-2002-14246
[0012]
[Patent Document 5]
JP 2000-265074A
[0013]
[Patent Document 6]
JP 05-185269 A
[0014]
[Problems to be solved by the invention]
In order to solve the problems of the prior art described above, a grating made of a polymer material, a lens array, a manufacturing method for easily manufacturing a Fresnel lens or a photonic crystal and a grating manufactured simply, a lens array, a Fresnel lens or It is to provide a photonic crystal.
[0015]
[Means for Solving the Problems]
In order to achieve the object, the grating, lens array, Fresnel lens or photonic crystal of the present invention has a portion in which the refractive index is changed by condensing irradiation of laser light, and is continuously formed inside and / or on the surface of the polymer material. It is characterized by being formed. In particular, the optical material is characterized in that the refractive index changing portion is an optical material that is periodically repeated. That is, the present invention
A grating or a lens array, a Fresnel lens, or a photonic crystal in which a portion whose refractive index has changed by condensing irradiation of a laser beam is formed of a polymer material. (Claim 1)
The grating, lens array, Fresnel lens, or photonic crystal according to claim 1, wherein the glass transition temperature (Tg) of the polymer material is 120 ° C or more. (Claim 2)
The polymer according to any one of claims 1 to 2, wherein the polymer material is any one of polyimide, polycarbonate, polyarylate, a polymer having a fluorinated aliphatic ring structure, an epoxy resin, a silicone resin, and a cyanate ester resin. Lens array or Fresnel lens or photonic crystal. (Claim 3)
The grating or lens array, the Fresnel lens, or the photonic crystal according to claim 1, wherein the polymer material is a polyimide or a cyanate ester resin. (Claim 4)
The grating, the lens array, the Fresnel lens, or the photonic crystal according to claim 1, wherein a light loss of the polymer material is 9 dB / cm or less at a wavelength of 600 nm to 1600 nm. (Claim 5)
A method for producing a grating, a lens array, a Fresnel lens, or a photonic crystal that forms a refractive index change portion at a focal point by interfering the laser light. (Claim 6)
The method according to claim 6, wherein the laser light is a laser light having an energy amount that causes a photo-induced refractive index change. (Claim 7)
8. The method for producing a grating, a lens array, a Fresnel lens or a photonic crystal according to claim 6, wherein the pulse width of the laser light is 500 psec or less. (Claim 8)
9. The method for producing a grating, a lens array, a Fresnel lens, or a photonic crystal according to claim 8, wherein the pulse width of the laser light is 500 ft or less. (Claim 9)
The peak power intensity at the focal point of the laser light is 10 ³ W / cm ² The method for manufacturing an optical waveguide according to any one of claims 6 to 9, which is described above. (Claim 10)
.
The gray according to any one of claims 6 to 10, wherein the polymer material is any of polyimide, polycarbonate, a polymer having a fluorine-based aliphatic ring structure, an epoxy resin, a silicone resin, a polysilane, and a cyanate ester resin. A method for producing a lens, a lens array, a Fresnel lens or a photonic crystal. (Claim 11)
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, regions having different refractive indices are formed by condensing and irradiating a laser beam of a polymer material, so that a grating, a lens array, a Fresnel lens, or a photonic crystal can be easily formed. . In particular, it can be made partially in a specific part of the optical component, and can also be made inside the material if necessary. For example, it is possible to produce a grating by irradiating only the core of the polymer optical fiber, or to produce a grating or a photonic crystal in the core of the polymer optical waveguide on a plane. In addition, since it can be manufactured only in a necessary portion, it is advantageous in terms of miniaturization and economy. Compared to a grating manufactured by heating and forming irregularities with a mold by heating a thermoplastic resin, it is preferable in that only necessary portions can be formed and that it can be widely manufactured without being limited to the thermoplastic resin.
In addition, it can be manufactured inside as compared with the case where a normal photoreactive resin is used, and is preferable in that the versatility of the resin is expanded.
[0017]
The laser beam applied to the polymer material that can be used in the present invention is not particularly limited as long as it is a laser beam capable of causing a change in the refractive index, but a region in which the refractive index has changed is continuously formed. For this purpose, it is preferable that the laser light has high energy.
[0018]
Such a laser beam is preferably a laser beam having a pulse width of 500 psec or less, more preferably 1 psec or less, and further preferably 500 ft sec or less. If the pulse width is wider than 500 psec, the desired change in refractive index may not be obtained. In addition, since the laser beam intensity can be used without amplifying the laser beam intensity with an amplifier with a pulse of 150 ft sec or less, particularly 50 to 5 ft sec, the apparatus is simplified and more preferable.
[0019]
When a high peak output was obtained by narrowing the pulse width of the laser, it was confirmed that, even in a pulse laser having a repetition frequency of, for example, 10 KHz or more, the refractive index changed at the focal point of the laser light on the polymer material. . Under this condition, even with a pulsed laser having a wavelength other than the intrinsic absorption wavelength of the polymer, a phenomenon occurs in which the photo-induced refractive index of the polymer is similarly changed at the focal point. For example, when a polymer having a wavelength of 800 nm and having no light absorption is used and a refractive index change is caused by a laser having a wavelength of 800 nm, a light-induced refractive index change occurs at a focal point and a laser beam path to the focal point. And no loss of laser light.
[0020]
Further, the peak power intensity at the focal point is 10 ³ W / cm ² It is preferable that this is the case. Even a pulsed laser having a wavelength that matches the intrinsic absorption wavelength of the polymer has a weak absorption, for example, 10% at the focal point. ³ W / cm ² When the above peak power intensity is secured, a photoinduced refractive index change occurs. Preferably 10 ⁵ W / cm ² That is it. The mechanism by which the change in the refractive index occurs is unknown, but the change in the refractive index of the material is used for manufacturing a grating or the like. Further, since the repetition period is fast, the refractive index change region can be formed in the polymer material in a short time.
[0021]
When a continuous change in the refractive index is required, it is necessary to shorten the pulse interval, that is, to increase the repetition period, and irradiate the first pulse and the second pulse as simultaneously as possible. For this reason, in this case, the repetition frequency of the pulse laser is set to preferably 10 KHz, more preferably 100 KHz or more. If the repetition frequency is small, laser light is radiated discretely, and a necessary continuous refractive index change cannot be obtained.
[0022]
Note that even when the repetition frequency is low, laser light can be continuously applied to the polymer material or the laser beam by reducing the scanning speed of the focal point of the laser beam. However, in this case, the irradiation is performed in a state where the second pulse overlaps with a certain time after the irradiation of the first pulse, so that the change in the refractive index formed by the first pulse is changed again by the second pulse, and No significant change in refractive index can be obtained. On the other hand, the upper limit of the repetition frequency is as close to a continuous laser as possible without the repetition frequency being infinite. However, when the repetition frequency is increased, the energy per pulse generally decreases. Therefore, the upper limit of the repetition frequency is actually set by the threshold value at which the polymer material causes a change in the refractive index and the output of the laser used.
[0023]
The change region of the refractive index can be controlled by changing the power of the pulsed laser or the diameter of the focused spot. As the power or the focused spot diameter of the pulse laser increases, the refractive index change region also increases. Further, the amount of change in the refractive index can be controlled by the number of irradiations of the pulse laser, and as the number of irradiations increases, the amount of change in the refractive index can be increased while keeping the change region constant. Further, it is also possible to form a region in which the refractive index changes substantially vertically by a light condensing method.
[0024]
It is also possible to process directly inside the material by adjusting the focusing area. It is also possible to perform three-dimensional processing, and when producing a photonic crystal or the like for exhibiting various functions, it is preferable because it is not necessary to laminate as in a usual production method.
[0025]
The rate of change of the refractive index by laser irradiation is preferably from 0.2% to 3%, more preferably from 0.3% to 2%. When the change in the refractive index is less than 0.2%, the difference in the refractive index from the unirradiated portion is too small and may not be a grating, a lens array, a Fresnel lens or a photonic crystal. Cracks may occur in the polymer.
[0026]
Irradiation of the polymer material with laser light can be performed by a method of continuously moving the polymer material with respect to the focal point or a method of continuously moving the laser light focal point inside the polymer material. preferable.
[0027]
It is also preferable in terms of productivity to produce a grating, a lens array, a Fresnel lens, or a photonic crystal by interfering laser light to create partial intensity shading.
[0028]
Examples of the polymer material used as the material include polyimide, polymaleimide, polyarylate, polycarbonate, polyurethane, polysulfide, polysulfone, polyamide, polyimine, polyurea, polysilane, polysilazane, polybenzoxazole, polyoxadiazole, and polybenzothiazole. , Polybenzimidazole, polystyrene, polyacrylic acid, polyacrylic acid ester, polymethacrylic acid, polymethacrylic acid ester, polyacrylamide, polymethacrylamide, polyetheretherketone, polyester, polysiloxane, polynorbornene, polyvinyl chloride, epoxy Resins, cellulose resins, silicon resins, cyanate ester resins, and fluorine resins are exemplified.
[0029]
Polyimides, polycarbonates, fluorine-based resins, especially polymers having a fluorine-based aliphatic ring structure, epoxy resins, silicone resins, and cyanate ester resins are preferred as those having excellent optical properties.
[0030]
The fluorine-containing aliphatic ring structure-containing polymer is, for example, a polymerized unit formed by cyclopolymerization of a fluorine-containing monomer having two or more polymerizable double bonds, and a fluorine-containing aliphatic ring structure-containing monomer Is a polymer having at least one type of polymerization unit selected from polymerization units formed by polymerization. In particular, the fluoromonomer having two or more polymerizable double bonds is perfluoro (allyl vinyl ether) or perfluoro (butenyl vinyl ether), and the fluoroaliphatic ring structure-containing monomer is perfluoro (2,2- Dimethyl-1,3-dioxole).
[0031]
Examples of the silicone resin include a polysiloxane, a modified silicone resin, and an acrylic silicone resin. Preferably, (A) an organic resin containing at least two carbon-carbon double bonds reactive with a SiH group in one molecule. An organic resin having a skeleton, (B) a silicon compound containing at least two SiH groups in one molecule, and (C) a hydrosilylation catalyst are essential components of a silyl group-containing organic resin.
[0032]
In particular, polyimide is preferable in terms of heat resistance, and containing fluorine is preferable in terms of optical characteristics and hygroscopicity. Among them, those having a structure in which 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and pyromellitic dianhydride are condensed, and 2,2'-bis (trifluoromethyl) -4 Those having a condensed structure of 4,4'-diaminobiphenyl are preferred in view of hygroscopicity and optical characteristics.
[0033]
Also, a cyanate ester resin is preferable from the viewpoint of heat resistance. The cyanate ester resin is obtained by polymerizing a monomer or oligomer having a cyanate ester group. Examples of the monomer include 1,3- or 1,4-dicyanobenzene, 2-tetrabutyl-1,4-dicyanobenzene, 2,4-dimethyl-1,3-dicyanobenzene, and 2,5-di-tetrabutyl- 1,4-dicyanobenzene, 4-chloro-1,3-dicyanobenzene, 1,3,5-tricyanobenzene, 2,2′- or 4,4′-dicyanobiphenyl, 3,3 ′, 5,5 '-Tetramethyl-4,4'-dicyanobiphenyl 1,3-, 1,4-, 1,5-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatonaphthalene; 1,3,6-tricyanatonaphthalene, 4,4′-dicyanatodiphenylmethane, bis (3-methyl-4-cyanatophenyl) methane, bis (3,5-dimethyl-4-cyanatophenyl) methane, bis (3,5-dibromo- -Cyanatophenylmethane, bis (3,5-dichloro-4-cyanatophenyl) methane, bis (4-cyanatophenyl) ethane, 2,2-bis (4-cyanatophenyl) propane, 2,2- Bis (3,5-dimethyl-4-cyanatophenyl) propane, 2,2-bis (3-methyl-4-cyanatophenyl) propane, 4,4′-dicyanatodiphenylthioether, 2,2-bis ( 4-cyanatophenyl) perfluoropropane, 1,1-bis (4-cyanatophenyl) ethane, 2,2-bis (3,5-dichloro-4-cyanatophenyl) propane, 2,2-bis ( 3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ketone, bis (4-cyanatophenyl) sulfone, tris (4-cyanatophenyl) phosph Such Aito and tris (4-cyan preparative phenyl) phosphate and those of some or all of these hydrogen atoms and fluorine atoms or deuterated. Also may be used an oligomer obtained by reacting these monomers.
[0034]
In many cases, the refractive index is reduced by laser light irradiation, but if it is desired to increase the refractive index of the laser light irradiated part, an oligomer or a monomer may be contained. It is preferable that the oligomer and the monomer are ion-reactive from the viewpoint of increasing the refractive index. It is particularly preferable that the oligomer and the monomer have an epoxy group, an oxetane group, a cyanate ester group and a maleimide group.
[0035]
Examples of those having a maleimide group include 1,2-bismaleimideethane, 1,3-bismaleimidebenzene, 1,6-bismaleimidehexane, 1,4-bismaleimidebenzene, 2,4-bismaleimidetoluene, 4'-bismaleimide diphenyl ether, 4,4'-bismaleimide diphenyl methane, 3,3'-bismaleimide diphenyl sulfone, 4,4'-bismaleimide diphenyl sulfone, 4,4'-bismaleimide dicyclohexyl methane, 2,6- Bismaleimidopyridine, 1,3-bis (maleimidomethyl) cyclohexane, 3,5'-bis (4-maleimidophenyl) pyridine, 1,3-bis (maleimidomethyl) benzene, 1,1-bis (4-maleimidophenyl) ) Cyclohexane, 1,3-bis (dichloromaleimide) Benzene, 2,2-bis (4-maleimidophenyl) propane, 4,4'-biscitraconimidodiphenylmethane, 1-phenyl-1,1-bis (4-maleimidophenyl) ethane, α, α-bis (4- Maleimidophenyl) toluene and 3,5-bismaleimide-1,2,4-triazole; those in which some or all of these hydrogen atoms have been replaced with deuterium or fluorine; and those which have been reacted to form an oligomer. May be used.
[0036]
Examples of monomers and oligomers having an epoxy group include various epoxies such as bisphenol A type epoxy, bisphenol F type epoxy, phenol novolak type epoxy, cresol novolak type epoxy, glycidyl ether type epoxy, naphthalene type epoxy and alicyclic epoxy. Can be used. An alicyclic epoxy is preferable because the refractive index is easily changed. Those in which some or all of these hydrogen atoms are replaced with deuterium or fluorine can be used.
[0037]
Examples of monomers and oligomers having an oxetane group include 3,3-bis (chloromethyl) oxetane, 3,3-bis (iodomethyl) oxetane, 3,3-bis (methoxymethyl) oxetane, and 3-methyl-3-chloromethyloxetane 3,3-bis (phenoxymethyl) oxetane, 3,3-bis (acetoxymethyl) oxetane, 3,3-bis (fluoromethyl) oxetane, 3,3-bis (bromomethyl) oxetane, 3,3-dimethyloxetane Etc. Those obtained by replacing some or all of these hydrogen atoms with deuterium or fluorine, or those obtained by reacting them to form oligomers may be used.
[0038]
Examples of the monomer or oligomer having a cyanate ester group include 1,3- or 1,4-dicyanobenzene, 2-tetrabutyl-1,4-dicyanobenzene, 2,4-dimethyl-1,3-dicyanobenzene, , 5-di-tetrabutyl-1,4-dicyanobenzene, 4-chloro-1,3-dicyanobenzene, 1,3,5-tricyanobenzene, 2,2′- or 4,4′-dicyanobiphenyl, , 3 ', 5,5'-Tetramethyl-4,4'-dicyanobiphenyl 1,3-, 1,4-, 1,5-, 1,6-, 1,8-, 2,6- or 2 , 7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatodiphenylmethane, bis (3-methyl-4-cyanatophenyl) methane, bis (3,5-dimethyl-4-) Cyanatophenyl) Tan, bis (3,5-dibromo-4-cyanatophenylmethane, bis (3,5-dichloro-4-cyanatophenyl) methane, bis (4-cyanatophenyl) ethane, 2,2-bis (4 -Cyanatophenyl) propane, 2,2-bis (3,5-dimethyl-4-cyanatophenyl) propane, 2,2-bis (3-methyl-4-cyanatophenyl) propane, 4,4′- Dicyanatodiphenylthioether, 2,2-bis (4-cyanatophenyl) perfluoropropane, 1,1-bis (4-cyanatophenyl) ethane, 2,2-bis (3,5-dichloro-4-cy Anatophenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanophenyl) ketone, bis (4-cyanophenyl) sulfone, Such as tris (4-cyanatophenyl) phosphite and tris (4-cyanotophenyl) phosphate, and those in which some or all of these hydrogen atoms are fluorine atoms or deuterated. Oligomers may be used.
[0039]
Further, a radical reactive group or an ion reactive group may be introduced into the polymer. This group is preferably at least one functional group selected from an epoxy group, an oxetane group, a cyanate ester group, and a maleimide group. The reactive group may be introduced by polymerizing a monomer having a reactive group.
[0040]
The glass point transition (Tg) of the polymer as the material is preferably 120 ° C. or higher, more preferably 150 ° C. or higher. When Tg is lower than 120 ° C., ablation is likely to occur, and it may be difficult to form a grating, a lens array, a Fresnel lens or a photonic crystal. In addition, long-term stability may be lacking.
[0041]
The polymer used as the material preferably has a light loss of 9 dB / cm or less at any of the wavelengths of 600 nm to 1600 nm. If it is larger than 9 dB / cm, the loss as a grating, a lens array, a Fresnel lens or a photonic crystal may be so large that it cannot be used. In addition, the absorption in the wavelength range of the laser beam is likely to cause ablation. It is not preferable in terms of point.
[0042]
When producing a grating (diffraction grating), it is possible to produce the portion by changing the refractive index repeatedly, or to produce it by laser interference. When the interference light is used, the periodic structure is preferably manufactured at a time. By changing the refractive index of the laser-irradiated portion, it is possible to periodically form a portion having a different refractive index repeatedly, so that the refractive index of the laser-irradiated portion can be increased or decreased. Good.
[0043]
Further, a grating can be formed on the fiber, and a functional optical fiber grating can be formed.
[0044]
【Example】
The raw materials used were purified from commercial products as necessary. Cyanogen bromide, isopropanol, triethylamine, toluene are Wako Pure Chemical Industries, 2,2-bis (4-hydroxyphenyl) -hexafluoropropane is Central Glass, and 2,2-bis (4-cyanatophenyl) propane is Lonza. The one obtained from Japan was used.
[0045]
Tg (glass transition temperature): The film-like sample was measured by DSC (differential scanning calorimeter: DSC-50 manufactured by Shimadzu Corporation) at a heating rate of 10 ° C./min.
[0046]
Refractive index measurement of a minute portion: Measured by a beam profile reflectivity measuring method at a wavelength of 675 nm, a beam spot of 1 μm, and a high-precision film thickness meter Opti-Probe2000 (manufactured by Thermawave).
[0047]
Preparation of Sample 1: (Synthesis of cyanate ester monomer) 30.0 g (0.26 mol) of cyanogen bromide was dissolved in 150 ml of isopropanol and cooled with ice while stirring. A solution obtained by dissolving 40.3 g (0.12 mol) of 2,2-bis (4-hydroxyphenyl) -hexafluoropropane in 150 ml of isopropanol and adding 24.9 g (0.25 mol) of triethylamine is added dropwise. After completion of the dropwise addition, stirring was continued for 1 hour, and the precipitate was filtered and washed with water to obtain 38.0 g of 2,2-bis (4-cyanatophenyl) hexafluoropropane as a white powder. 1 g of this 2,2-bis (4-cyanatophenyl) hexafluoropropane and 1 g of 2,2-bis (4-cyanatophenyl) propane were mixed and heated at 100 ° C. for 10 minutes. The mixture became liquid and uniform when heated. This solution was cast on a glass substrate and heated at 150 ° C. for 3 hours and further at 200 ° C. for 1 hour under a nitrogen atmosphere to obtain a cyanate ester resin film (II) having a thickness of 1 m. When the Tg of this film was measured, it was 200 ° C. or higher.
[0048]
(Example 1)
As a sample 1, a cyanate ester resin film (I) was used.
As shown in the figure, a pulse laser beam 1 was condensed by a lens 2 and irradiated. As the pulse laser beam 1, a laser having a pulse width of 150 femtoseconds, a repetition frequency of 200 KHz, a wavelength of 800 nm, and an average output of 200 mW oscillated from a Ti: Al2O3 laser excited by an argon laser was used with an optical filter having an average output of 8 mW. When the pulse laser beam 1 was condensed by the lens 2 and irradiated so as to form the focal point 4 inside the cyanate ester resin film (I), the refractive index of the focal point 4 changed. Therefore, the sample stage was continuously linearly moved, and FIG.
It is confirmed by observation with an optical microscope that a line that is clearly different from the linear periphery is formed inside the sample 3 along the locus of the focal point 4 as shown in FIG. You.
[0049]
Further, when the cross section of the sample was polished and the refractive index of the minute portion was measured, the non-irradiated portion was 1.570, and the refractive index of the irradiated portion was lowered. The lowest portion was 1.557, which was 0.8%. Was lowered. The refractive index was lower toward the center of the irradiated part.
[0050]
Then, when scanning on the above-mentioned straight line having a width of 1 m was repeated 100 times at intervals of 5 μm, a grating could be produced. When the light of the He-Ne laser was applied perpendicularly to the produced film, it was confirmed that the laser light was divided into three lines and functioned as a grating (diffraction grating).
[0051]
As described above, according to the present invention, the polymer material is graded by irradiating the polymer material with a pulse laser having a high peak output value and changing the refractive index at the focal point. And so on. This method has an advantage that it can be easily formed without going through a complicated process, and a flexible optical waveguide can be obtained because a polymer material is used. In addition, the shape can be controlled arbitrarily by changing the scanning direction of the polymer material with respect to the optical axis direction of the pulse laser or the moving direction of the focal point with respect to the polymer material, and is suitable for optical integrated circuits with complicated circuit structures. A three-dimensional Fresnel lens or photonic crystal can also be easily produced.
[Brief description of the drawings]
FIG. 1 is a simplified cross-sectional view when a sample is irradiated with a pulsed laser beam.
FIG. 2 is a perspective view of a refractive index changing portion formed inside a sample.
[Explanation of symbols]
1: pulsed laser light
2: Condensing lens
3: Sample
4: Focus point
5: Sample table
6: Refractive index change part

Claims (11)

A grating, a lens array, or a photonic crystal in which a portion whose refractive index is changed by condensing irradiation of a laser beam is formed of a polymer material. The grating, lens array, Fresnel lens, or photonic crystal according to claim 1, wherein the glass transition temperature (Tg) of the polymer material is 120 ° C or more. 3. The grating, lens array or full lens according to claim 1, wherein the polymer material is any one of polyimide, polycarbonate, polyarylate, a polymer having a fluorinated aliphatic ring structure, epoxy resin, silicone resin, polysilane and cyanate ester resin. Flannel lens or photonic crystal. The grating, the lens array, the Fresnel lens, or the photonic crystal according to claim 1, wherein the polymer material is a polyimide or a cyanate ester resin. The grating or lens array, the Fresnel lens, or the photonic crystal according to claim 1, wherein a light loss of the polymer material is 9 dB / cm or less at any wavelength of 600 nm to 1600 nm. A method for producing a grating, a lens array, a Fresnel lens, or a photonic crystal that forms a refractive index change portion at a focal point by causing the laser light to interfere. The method according to claim 6, wherein the laser light is a laser light having an energy amount that causes a photo-induced refractive index change. 8. The method for producing a grating, a lens array, a Fresnel lens or a photonic crystal according to claim 6, wherein a pulse width of the laser light is 500 psec or less. The method for producing a grating, a lens array, a Fresnel lens or a photonic crystal according to claim 8, wherein the pulse width of the laser light is 500 ft or less. The method of manufacturing an optical waveguide according to any one of claims 6 to 9, wherein a peak power intensity at a focal point of the laser beam is 10 ³ W / cm ² or more.
. The gray according to any one of claims 6 to 10, wherein the polymer material is any of polyimide, polycarbonate, a polymer having a fluorine-based aliphatic ring structure, an epoxy resin, a silicone resin, a polysilane, and a cyanate ester resin. A method for producing a lens, a lens array, a Fresnel lens, or a photonic crystal.

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