JPS6315203A - Diffraction element - Google Patents

Abstract

PURPOSE:To easily obtain a diffraction grating having good quality and characteristics with high accuracy by providing a substrate and grating forming layer and partially forming transparent porous oxide films made of aluminum having many pores orthogonal with the substrate surface to the grating forming layer thereby forming the diffraction grating. CONSTITUTION:This diffraction element is provided with the substrate 1 made of the aluminum, the grating forming layer 2 integrally formed on the surface of the substrate 1 and the many transparent porous oxide films 3 formed on the grating forming layer 2 at parallel intervals spaced from each other. Each porous oxide film 3 consists of an upper porous part 4 and a lower barrier part 5. The porous part 4 has the structure in which respective hexagonal columnar cells 7 having fine pores 6 are continuous to a plane shape. The diffraction gratings 8 are formed to the substrate 1 by the porous oxide films 3. The pores 6 of the porous oxide films 3 are sometimes sealed by a sealing material 9 made of metals, dyes, dielectric, etc., in order to adjust the refractive index. The diffraction element which can satisfy the quality, price, ease of manufacture, reproducibility, etc., is thereby obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a diffraction element (deflection element) used in optical communication, optical information processing, and other fields.

2. Prior Art As is well known, diffraction elements that form diffraction gratings are widely used in spectrometers, multiplexers/demultiplexers, etc., and the method for manufacturing such diffraction gratings is to create a master.

A method using a replica copied from the master is known.

In the above method, the All plating layer formed on the glass surface after polishing is cut with, for example, a diamond canter to form a large number of parallel grooves (one thin groove), and after this, a master is produced. Create a replica using the master as the original.

The spacing between the parallel grooves, that is, the grating spacing, varies depending on the purpose of use, but is usually about the wavelength of light.

``The north point that the invention attempts to solve'' In the case of the conventional example described above, since the lattice spacing is as small as a wavelength, it is extremely difficult to manufacture and requires advanced technology.

In particular, cutting deep narrow grooves, and
It is difficult to form such narrow grooves over a wide area with a large number of forces, and therefore it is impossible to obtain a high-quality, inexpensive diffraction grating with good visibility and stability.

In view of the above-mentioned problems, the present invention has been developed to improve quality, price, manufacturing speed,
The present invention aims to provide a diffraction element that can satisfy reproducibility and the like.

Means for Solving Problem T" In order to achieve the intended purpose, the diffraction element according to the present invention has the following features:
The method comprises a substrate and a lattice forming layer provided on an arbitrary surface of the substrate, and the lattice forming layer is partially formed with a transparent porous oxide film on an aluminum plate having a large number of holes perpendicular to the surface of the substrate. It is characterized in that a diffraction grating is formed.

1. In the case of the diffraction element according to the present invention, partial formation of a porous oxide film in the grating formation layer provided on the surface of the substrate, sealing of the porous oxide film, etc. are all performed by electrical/chemical means. Therefore, a diffraction grating with good quality and characteristics can be easily obtained with high precision without using mechanical processing methods that are difficult to manufacture.

"Example" Examples of the diffraction element of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show a reflection type plane diffraction element.

In FIGS. 1 and 2, 1 is an aluminum substrate;
2 is a grating forming layer integrally formed on the surface of the substrate l, and 3 is a large number of transparent porous oxide films formed on the grating forming layer 2 at parallel intervals.

As shown in FIG. 2, the porous oxide film 3 has an upper porous portion 4
and a lower barrier part 5, and the porous part 4 has a structure in which each hexagonal columnar self having pores 6 is continuous in a planar manner. A diffraction grating 8 is formed.

In addition, in order to adjust the refractive index, the pores 6 of the porous oxide film 3
The sealing material 9 is made of metal or dye.

The pores may be sealed with a pore sealing material 9 made of dielectric or the like.

In addition, the diffraction grating 8 formed as described above can be formed in a single row pattern, a structure consisting of a plurality of concentric circles as shown in FIG. can be adopted.

In the embodiments described above, the surface of the grating forming layer 2 may be covered with a cladding material such as glass or plastic, if necessary.

Next, a manufacturing example of the diffraction element of the present invention will be explained in detail with reference to FIG.

The substrate 1 in FIG. 4(a) has a purity of 99.9!31 and an IOc
It was obtained by electrolytically polishing a ++1 square AI plate, washing it with ethyl alcohol, and drying it, and its surface has a perfect mirror finish.

Next, as shown in FIG. 4 (b), after coating the surface of the substrate 1 with acid-resistant resist 10, a diffraction grating of 500 mm/mm was written on the surface using three-beam interferometry. Patterning of the diffraction grating was performed.

Note that exposure of one diffraction grating can also be performed by an exposure method using a mask pattern.

The anodic oxidation method using the substrate 1 as an anode and an aluminum flat plate as a cathode was carried out in a 15:H2SO4 bath at a bath temperature of 22°C, with an applied voltage of 60 V and an anode current of about 1.3 A/.
The process was carried out under the conditions of dm2 and processing time of 230 minutes, and transparent porous oxide films 3 having a thickness of about 10 ml were formed on the surface of the substrate 1 at parallel intervals to obtain a lattice forming layer 2.

The porous oxide film 3 is as described in FIG. 2 above,
The self size is about 0.157ia+, the volume ratio of pores 2 is about 2z, and the refractive index is about 1.61.

Note that the pore 8 = bore diameter and self size can be changed by the above-mentioned applied voltage, and the pore diameter can be expanded by bore widening.

After that, as shown in FIG. 4(c), the grating forming layer 2 of the substrate 1 is
The resist lO is removed from the photoresist to obtain a diffraction grating 8 as shown in FIG.

When using the method shown in FIG. 4, the diffraction grating 8 becomes parallel as shown in FIG. 1, but by changing the patterning mode, the diffraction grating 8 shown in FIG. 3 can be obtained.

"Effects of the Invention" As explained above, the diffraction violet of the present invention includes a substrate and a grating forming layer provided on an arbitrary surface of the substrate, and the grating forming layer has a large number of layers perpendicular to the surface of the substrate. Since the diffraction grating is formed by partially forming a transparent porous oxide film made of aluminum having holes, the diffraction element can be obtained through anodization, and the quality, price, and The production level, reproducibility, etc. can be satisfied.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing an embodiment of the diffraction element of the present invention;
Fig. 2 is an enlarged view of the main part of the diffraction element, Fig. 3 is an explanatory diagram showing the other side of the diffraction grating pattern, and Fig. 4 is an explanation schematically showing an example of manufacturing the diffraction element of the present invention in step 1. It is a diagram. l...substrate, 2... grating forming layer, 3.
... Porous oxide film, 4 ... Porous part, 5
... Barrier part, 6 ... Pore, 7 ...
...Cell, 8...Diffraction grating. Agent: Patent Attorney Yoshio Saito Figure 2, Figure 4. Evil

Claims (3)

[Claims] (1) Comprising a substrate and a lattice-forming layer provided on an arbitrary surface of the substrate, the lattice-forming layer is partially covered with a transparent porous oxide film made of aluminum having a large number of holes orthogonal to the substrate surface. A diffraction element characterized in that a diffraction grating is formed by forming a diffraction grating. (2) The diffraction element according to any one of claims 1 to 3, wherein the grating forming layer has porous oxide films formed at parallel intervals. (3) The diffraction element according to any one of claims 1 to 3, wherein the grating forming layer has a plurality of concentric porous oxide films formed thereon.