JP2004126114A - Method for adjusting optical characteristic of photonic crystal, and method and apparatus for manufacturing optical element using optical characteristic adjusting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical characteristic adjusting method for photonic crystal which is high in degree of freedom of material selection and can be made compact and reduced in cost and continuously maintain a state in which the crystal is adjusted to a desired optical characteristic, and to provide a manufacturing method and a manufacturing apparatus for optical element which use the optical characteristic adjusting method. <P>SOLUTION: In the optical characteristic adjusting method for photonic crystal, the photonic crystal is deformed by using a mechanical external force applying means to adjust optical characteristics of the photonic crystal and the deformation state of the photonic crystal is fixed. The manufacturing method and manufacturing apparatus for optical element use the optical characteristic adjusting method and the mechanical external force applying means is removed after the deformation state is fixed to complete the optical element. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for adjusting optical properties of a photonic crystal, a method for manufacturing an optical element using the method for adjusting optical properties, and an apparatus for manufacturing an optical element.
[0002]
[Prior art]
In recent years, a new artificial crystal called “photonic crystal” in which substances having different refractive indices are periodically arranged at intervals of about a wavelength has been proposed (E. Yablonovitch, Phys. Rev. Lett., 58 (1987) 2059- 2062), attracting attention. This artificial crystal exhibits unique optical characteristics, such as the band gap of light and apparent refractive index anomalies caused by the so-called photonic band structure, similar to the band structure of semiconductors. Therefore, research and development as an optical element have been actively conducted.
[0003]
One of the things that attracts attention in these researches and developments is an optical element whose characteristics can be adjusted. This is an element whose optical characteristics can be actively controlled not only at the time of design but also from outside during use, and is expected to be applied to a wide range of fields such as a variable filter and an optical switch.
[0004]
As such a prior art, a method has been proposed in which an actuator is arranged around a fiber diffraction grating and the fiber is stretched to apply tension to the fiber, thereby controlling the refractive index distribution in the fiber (for example, Patent Document 1). 1).
Further, a method has been proposed in which a substance such as a piezoelectric element, whose refractive index and transmittance can be externally controlled, is introduced into a crystal, and the periodicity of the crystal is disturbed by expansion and contraction and characteristic change of the substance (see Patent Document 2). .
Also, a method has been proposed in which pressure is applied to the photonic crystal from the outside to control the lattice spacing (see Patent Document 3).
[0005]
[Patent Document 1] Japanese Patent Application Laid-Open No. 10-253829 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-091911 [Patent Document 3] Japanese Patent Application Laid-Open No. 2002-098916
[Problems to be solved by the invention]
By the way, one of the important issues for practical use of a photonic crystal is a problem of processing accuracy. As described above, the period of the structure constituting the photonic crystal is very small, about half of the light used, and the optical characteristics vary greatly depending on the size of the individual members constituting the periodic structure. , A processing accuracy of about several to 10 nm is required. Even with the most advanced processing technology at present, it is inevitable that the yield at the time of manufacturing is reduced for such accuracy requirements.
[0007]
There are also other cost concerns. Even taking lithography technology using electron beams, X-rays, EUV, etc. as an example, not only must expensive masks be prepared for each wavelength used, but also photomasks must be used to meet the above-mentioned accuracy requirements. It may be necessary to apply a different design to the nick crystal itself for each operating temperature with respect to the thermal expansion of the nick crystal itself.
[0008]
To cope with such a problem, it is of course possible to adjust the manufactured photonic crystal at the time of use using the above-described methods.
However, for example, in Patent Literature 1 and Patent Literature 3 described above, since an external force is applied to the photonic crystal, an actuator that operates accurately and precisely as described above is always required. Such an actuator is generally expensive and large, which leads to an increase in the cost and size of the entire device.
Also, in Patent Document 2 described above, it is necessary to provide a means for disturbing the crystal structure in the photonic crystal, which complicates the operation steps during manufacturing. In addition, usable materials are greatly limited.
[0009]
Therefore, the present invention solves the above-mentioned problems, has a high degree of freedom in material selection, can achieve compactness and low cost, and can continuously maintain a state adjusted to desired optical characteristics. It is an object of the present invention to provide a method for adjusting optical characteristics of a photonic crystal, a method for manufacturing an optical element using the method for adjusting optical characteristics, and an apparatus for manufacturing an optical element.
[0010]
[Means for Solving the Problems]
The present invention provides a method for adjusting optical characteristics of a photonic crystal, a method for manufacturing an optical element using the method for adjusting optical characteristics, and an apparatus for manufacturing an optical element, configured as follows.
The method for adjusting optical characteristics of the present invention comprises the steps of: deforming a photonic crystal by using a mechanical external force applying unit, adjusting the optical characteristics of the photonic crystal; and deforming the optical characteristics of the photonic crystal at the adjusted position. Fixing the state.
Further, the method for manufacturing an optical element of the present invention uses the method for adjusting the optical characteristics of the photonic crystal, and in the step of fixing the deformation state of the photonic crystal, after the deformation state of the photonic crystal is fixed, It is characterized in that the mechanical external force applying means is removed and an optical element adjusted to desired optical characteristics is produced.
Further, the apparatus for manufacturing an optical element according to the present invention includes a detachable mechanical external force applying means for deforming the photonic crystal by an external mechanical external force, and an optical system for the photonic crystal deformed by the mechanical external force applying means. It is characterized by having means for adjusting characteristics and means for fixing a deformed state at a position where the optical characteristics of the photonic crystal are adjusted.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
In the embodiment of the present invention, by applying the above configuration, for example, in the adjustment stage after manufacturing, after adjusting the optical characteristics by deforming the photonic crystal, the movable portion of the fixed member is bonded. After the actuator is removed and used as an optical element by fixing, the photonic crystal is heated and softened, and the photonic crystal is deformed to adjust the optical characteristics. By cooling and hardening, the deformed state can be maintained continuously. Therefore, by removing the actuator and the heater after adjusting the optical characteristics in this way, it is possible to form an optical element that can continuously maintain the state adjusted to the desired optical characteristics.
Further, according to the above configuration, there is little restriction on members, the degree of freedom in selecting a material is increased, and a material that simplifies the manufacturing process can be appropriately selected. Thus, a compact and low-cost optical characteristic adjustment method is provided. can do.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Example 1]
FIG. 1 is a diagram showing a device configuration of a device for manufacturing an optical element according to the present embodiment.
As shown in FIG. 1, a photonic crystal 101 made of PMMA (polymethyl methacrylate) is surrounded by a first fixed member 102 and a second fixed member 103 which are relatively movable. The photocurable resin 104 is disposed between the two members.
The actuator 105 expands and contracts in the direction indicated by the expansion and contraction direction 114 in the figure, is connected to the first fixing member 102 via the pressing member 106, and deforms the photonic crystal 101. In each of these mechanisms, the actuator 105 is connected to the first housing member 107 and the second fixing member 103 is connected to the second housing member 108, and is housed in a split housing composed of both housing members. Can be
[0013]
The first casing member 107 and the second fixing member 103 are provided with holes on both sides of the photonic crystal 101 to secure an optical path, and the laser light from the laser 112 passes through the optical path. The light passes through the photonic crystal 101 and enters the light receiver 111. The light receiver 111 includes a photodiode, and sends the intensity of the incident light to the control circuit 109.
The control circuit 109 calculates a control amount and sends it to the drive circuit 110 so that the amount of light incident on the light receiver 111 becomes a desired value, drives the actuator 105, and deforms the photonic crystal 101.
[0014]
When the amount of light incident on the light receiver 111 reaches a desired value, the control circuit 109 turns on the light source 113. Ultraviolet light from a light source 113 composed of an ultraviolet lamp passes through a window (not shown) opened in the first housing 107 to cure the photocurable resin 104. Thereby, the positional relationship between the first fixing member 102 and the second fixing member 103 is fixed, and the amount of deformation of the photonic crystal 101 is maintained.
[0015]
Finally, the laser 112 and the light source 113 are turned off, and the mechanisms other than the photonic crystal 101, the first fixing member 102, the second fixing member 103, and the photo-curing resin 104 are removed. An optical element having the above optical characteristics is completed.
The material of the photonic crystal 101 is not limited to the above-described example, and may be appropriately selected from physical characteristics such as a refractive index and a Young's modulus, process compatibility at the time of fabrication, and compatibility with a use environment such as temperature and humidity. It is possible.
[0016]
In the present embodiment, a piezoelectric element is used as the actuator 101, but other driving mechanisms such as a feed screw mechanism and a voice coil can be selected.
Further, in the present embodiment, a light-curing resin is used to fix the positional relationship between the first fixing member 102 and the second fixing member 103, but other fixing means such as a thermosetting resin or screw fixing may be used. It is also possible to select.
Further, in the present embodiment, the present invention is applied to the adjustment of the transmittance as an optical characteristic, but it is needless to say that the present invention can be applied to other optical characteristics such as a reflectance.
[0017]
[Example 2]
FIG. 3 is a diagram illustrating a device configuration of a device for manufacturing an optical element of the present embodiment.
As shown in FIG. 3, a photonic crystal 101 made of PMMA (polymethyl methacrylate) is connected to an actuator 105 via a heater 201 and a heat insulating member 202.
The actuator 105 expands and contracts in the direction indicated by the expansion and contraction direction 114 in the figure, and deforms the photonic crystal 101. In each of these mechanisms, the actuator 105 is connected to the first housing member 107 and the photonic crystal 101 is connected to the second housing member 108, and are housed in a divisible housing composed of both housing members.
[0018]
The first housing member 107 is provided with holes on both sides of the photonic crystal 101 in order to secure an optical path, and laser light from the laser 112 passes through the optical path and passes through the photonic crystal 101. , Incident on the light receiver 111. The light receiver 111 includes a photodiode, and sends the intensity of the incident light to the control circuit 109. The control circuit 109 energizes the heater 201 and heats the photonic crystal 101 until it softens, then calculates a control amount and sends it to the drive circuit 110 so that the amount of light incident on the light receiver 111 becomes a desired value. Then, the actuator 105 is driven to deform the photonic crystal 101.
[0019]
When the amount of light incident on the light receiver 111 reaches a desired value, the control circuit 109 turns off the power of the heater 201 and cools and cures the photonic crystal 101. As a result, the amount of deformation of the photonic crystal 101 is continuously maintained.
Finally, the laser 112 is turned off, the first housing member 107 and the second housing member 108 are divided, and the photonic crystal 101 is taken out, so that desired optical characteristics can be continuously maintained. The device is completed.
In addition, the material of the photonic crystal 101 is not limited to the above-described example, and physical properties such as a refractive index and a Young's modulus, process suitability at the time of fabrication, and use environment such as temperature and humidity are selected from thermoplastic materials. Can be selected as appropriate based on the suitability for.
[0020]
In the present embodiment, a piezoelectric element is used as the actuator 101, but other driving mechanisms such as a feed screw mechanism and a voice coil can be selected.
Further, in the present embodiment, the present invention is applied to the adjustment of the transmittance as an optical characteristic, but it is needless to say that the present invention can be applied to other optical characteristics such as a reflectance.
[0021]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the degree of freedom of material selection is high, compactness and cost reduction can be achieved, and it is possible to continuously maintain a state adjusted to desired optical characteristics. A method for adjusting characteristics, a method for manufacturing an optical element using the method for adjusting optical characteristics, and an apparatus for manufacturing an optical element can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an apparatus configuration of an optical element manufacturing apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a configuration of an optical element according to a first embodiment of the present invention.
FIG. 3 is a diagram illustrating an apparatus configuration of an optical element manufacturing apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
101: Photonic crystal 102: First fixing member 103: Second fixing member 104: Photocurable resin 105: Actuator 106: Pressing member 107: First housing member 108: Second housing member 109: Control Circuit 110: drive circuit 111: light receiver 112: laser 113: light source 114: expansion / contraction direction 201: heater 202: heat insulating member

Claims (8)

Deforming the photonic crystal using mechanical external force applying means, and adjusting the optical characteristics of the photonic crystal;
Fixing a deformed state at a position where the optical characteristics of the photonic crystal are adjusted,
A method for adjusting optical characteristics of a photonic crystal, comprising: In the step of fixing the deformed state of the photonic crystal, a holding member for holding the deformed state of the photonic crystal deformed by the mechanical external force applying means, and a holding state of the photonic crystal deformed by the holding member The method for adjusting optical characteristics of a photonic crystal according to claim 1, wherein the deformed state is fixed by using fixing means for fixing the holding member at a position where the photonic crystal is deformed. 3. The method according to claim 2, wherein the fixing unit is a unit that uses a light-curing material or a thermosetting material, and irradiates the material with light or applies heat to fix the deformed state of the photonic crystal. The method for adjusting optical characteristics of the photonic crystal according to the above. In the step of deforming the photonic crystal and adjusting the optical characteristics of the photonic crystal, the photonic crystal is made of a thermoplastic material, and after heating the photonic crystal, the photonic crystal is deformed by using a mechanical external force applying unit. on the other hand,
The photo-crystal according to claim 1, wherein, in the step of fixing the deformed state at the position where the optical characteristics of the photonic crystal have been adjusted, the deformed state is fixed by cooling the deformed photonic crystal after the heating. A method for adjusting the optical characteristics of a nick crystal. 5. A method for producing an optical element, comprising: using the method for adjusting optical characteristics of a photonic crystal according to claim 1, wherein the step of fixing a deformed state of the photonic crystal includes the step of: After the deformation state of the nick crystal is fixed, the mechanical external force applying means is removed, and an optical element adjusted to desired optical characteristics is manufactured. Detachable mechanical external force applying means for deforming the photonic crystal by external mechanical external force,
Means for adjusting the optical characteristics of the photonic crystal deformed by the mechanical external force applying means,
Means for fixing a deformed state at a position where the optical characteristics of the photonic crystal are adjusted,
An apparatus for manufacturing an optical element, comprising: 7. The apparatus for manufacturing an optical element according to claim 6, wherein the fixing means comprises a light-curing material or a thermosetting material, and a means for irradiating the material with light or a means for applying heat. The fixing unit heats a photonic crystal made of a thermoplastic material by a heating unit, deforms the same using the mechanical external force applying unit, and then cools the photonic crystal to fix the deformed state. 7. The apparatus for manufacturing an optical element according to claim 6, comprising:

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