JP2799011B2 - Magneto-optical element and method of manufacturing the same - Google Patents
Magneto-optical element and method of manufacturing the sameInfo
- Publication number
- JP2799011B2 JP2799011B2 JP29217689A JP29217689A JP2799011B2 JP 2799011 B2 JP2799011 B2 JP 2799011B2 JP 29217689 A JP29217689 A JP 29217689A JP 29217689 A JP29217689 A JP 29217689A JP 2799011 B2 JP2799011 B2 JP 2799011B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- magneto
- faraday rotation
- optical element
- magnetic garnet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- 239000013078 crystal Substances 0.000 claims description 30
- 239000002223 garnet Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 18
- 239000000758 substrate Substances 0.000 claims description 11
- 238000006467 substitution reaction Methods 0.000 claims description 2
- 238000004943 liquid phase epitaxy Methods 0.000 claims 2
- 239000010408 film Substances 0.000 description 19
- 101100343606 Arabidopsis thaliana LOG2 gene Proteins 0.000 description 6
- 101100206349 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) TFB3 gene Proteins 0.000 description 6
- 239000010409 thin film Substances 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 229910015372 FeAl Inorganic materials 0.000 description 1
- 230000010485 coping Effects 0.000 description 1
- 238000002845 discoloration Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Landscapes
- Thin Magnetic Films (AREA)
Description
【発明の詳細な説明】 《産業上の利用分野》 本発明は、光アイソレータや光スイッチ等に使用され
る磁気光学素子及びその製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION << Industrial application field >> The present invention relates to a magneto-optical element used for an optical isolator, an optical switch, and the like, and a method for manufacturing the same.
《従来の技術》 上記の磁気光学素子は、ファラデー回転角度θＦが45
度（45deg）になるように調整する必要がある。<< Conventional Technology >> The above-mentioned magneto-optical element has a Faraday rotation angle θF of 45 °.
It is necessary to adjust the temperature to 45 degrees.
従来のFZ法で育成されるYIG（Y3Fe5O12バルク）は、
ファラデー回転係数θＦ（deg/cm）が極めて小さく、1.
31μｍ帯用の磁気光学素子とする場合は、45度のファラ
デー回転角度に調整するために、2.0mm以上もの長さに
結晶を成長させる必要があった。YIG (Y 3 Fe 5 O 12 bulk) grown by the conventional FZ method is
The Faraday rotation coefficient θF (deg / cm) is extremely small,
In the case of a magneto-optical element for the 31 μm band, it was necessary to grow a crystal to a length of 2.0 mm or more in order to adjust the Faraday rotation angle to 45 degrees.
このため、製造コストが高額になる上、デバイスが大
型化する等の問題があった。For this reason, there have been problems such as an increase in manufacturing cost and an increase in the size of the device.
このような問題を解決するために、近年、希土類元素
の一部をBiで置換したいわゆるBi置換磁性ガーネット単
結晶からなる磁気光学素子が広く研究されるようになっ
た。In order to solve such a problem, in recent years, a magneto-optical element made of a so-called Bi-substituted magnetic garnet single crystal in which a part of a rare earth element is substituted with Bi has been widely studied.
このBi置換磁性ガーネット単結晶は、Bi置換量を多く
するとファラデー回転係数θＦ（deg/cm）が大きくな
り、1500以上にもなる。このため、45度のファラデー回
転角度に調整するためには、数百μｍ程度の長さに結晶
を成長（一般には、液相エピタキシャル法［以下、LPE
法］により成長）させるだけで充分である。In the Bi-substituted magnetic garnet single crystal, the Faraday rotation coefficient θF (deg / cm) increases as the amount of Bi substitution increases, and reaches 1500 or more. Therefore, in order to adjust the Faraday rotation angle to 45 degrees, a crystal is grown to a length of about several hundred μm (generally, a liquid phase epitaxial method [hereinafter, LPE).
Method) is sufficient.
従って、Bi置換磁性ガーネット単結晶によれば、上記
したYIGによる場合に比し、磁気光学素子の製造コスト
が低減し、かつデバイスも小型化し得る。Therefore, according to the Bi-substituted magnetic garnet single crystal, the manufacturing cost of the magneto-optical element can be reduced and the device can be downsized, as compared with the case of the above-described YIG.
《発明が解決しようとする課題》 上記のように、Bi置換磁性ガーネット単結晶では、数
百μｍ（一般には、300μｍ）程度の極く薄い膜である
ため、ファラデー回転角θＦが44.5≦θＦ≦45.5度の規
格に入るように、上記薄膜の厚さを高精度で加工するこ
とは、極めて困難である。<< Problems to be Solved by the Invention >> As described above, a Bi-substituted magnetic garnet single crystal is a very thin film of about several hundred μm (generally, 300 μm), so that the Faraday rotation angle θF is 44.5 ≦ θF ≦ It is extremely difficult to process the thickness of the thin film with high precision so as to meet the standard of 45.5 degrees.
また、LPE法により毎回ファラデー回転係数θＦ（deg
/cm）の同一のものが育成できるとは限らないため、量
産化するにはこの変化するファラデー回転係数に対応す
る技術も重要となる。In addition, the Faraday rotation coefficient θF (deg.
/ cm) is not always possible to grow, so technology for coping with this changing Faraday rotation coefficient is also important for mass production.
すなわち例えば、RBiIG（R:希土類元素）において、
ファラデー回転係数θＦ（deg/cm）を1500とすると、膜
厚が１μｍ変化すると、ファラデー回転角度θＦは0.15
deg変化することになる。故に、ファラデー回転角度θ
Ｆを±0.5degの範囲内に入れるためには、θＦ＝45deg
なる膜厚に対して±3.3μｍと許容幅の極く小さい加工
精度としなければならない。That is, for example, in RBiIG (R: rare earth element),
Assuming that the Faraday rotation coefficient θF (deg / cm) is 1500, when the film thickness changes by 1 μm, the Faraday rotation angle θF becomes 0.15.
deg will change. Therefore, the Faraday rotation angle θ
To make F fall within the range of ± 0.5deg, θF = 45deg
The processing accuracy must be extremely small with an allowable width of ± 3.3 μm for a given film thickness.
このように、Bi置換磁性ガーネット単結晶による場合
は、数百μｍという極く薄い膜厚を高精度で加工する必
要があり、加工コスト、延いては製品コストが大幅に増
加する。As described above, in the case of using a Bi-substituted magnetic garnet single crystal, it is necessary to process an extremely thin film having a thickness of several hundreds of micrometers with high accuracy, and the processing cost and, consequently, the product cost are greatly increased.
本発明は、以上の諸点に鑑みてなされたもので、その
目的するところは、加工技術が容易で製品コストの安価
な磁気光学素子とその製造方法を提案するにある。The present invention has been made in view of the above points, and an object of the present invention is to propose a magneto-optical element which is easy in processing technology and inexpensive in product cost, and a method of manufacturing the same.
《課題を解決するための手段》 上記目的を達成するために本発明の磁気光学素子で
は、Bi非置換磁性ガーネット単結晶の片面にBi置換磁性
ガーネット単結晶が積層されてなることを特徴とする。<< Means for Solving the Problems >> In order to achieve the above object, the magneto-optical element of the present invention is characterized in that a Bi-substituted magnetic garnet single crystal is laminated on one surface of a Bi non-substituted magnetic garnet single crystal. .
また、上記磁気光学素子を製造するに適した方法とし
ては、非磁性ガーネット単結晶基板上にBi非置換磁性ガ
ーネット単結晶を液相エピタキシャル法により育成さ
せ、ついでそのBi非置換単結晶上にBi置換磁性ガーネッ
ト単結晶を液相エピタキシャル法により育成させた後、
少なくとも前記非磁性ガーネット単結晶基板と、Bi非置
換単結晶の一部を除去するようにした。In addition, as a method suitable for manufacturing the magneto-optical element, a Bi-unsubstituted magnetic garnet single crystal is grown on a non-magnetic garnet single crystal substrate by a liquid phase epitaxial method, and then a Bi-substituted single crystal is grown on the Bi-unsubstituted single crystal. After growing a substituted magnetic garnet single crystal by a liquid phase epitaxial method,
At least a part of the nonmagnetic garnet single crystal substrate and a part of the Bi non-substituted single crystal are removed.
《作 用》 本発明に係る磁気光学素子は、Bi非置換磁性ガーネッ
ト単結晶（以下、RIG）の膜（ファラデー回転係数が小
さい）と、Bi置換磁性ガーネット単結晶（以下、RBiI
G）の膜（ファラデー回転係数が大きい）とが積層され
たものであり、両膜の厚さを調整して所望のファラデー
回転角θＦを得る。<< Operation >> The magneto-optical element according to the present invention comprises a Bi-substituted magnetic garnet single crystal (hereinafter, RIG) film (having a small Faraday rotation coefficient) and a Bi-substituted magnetic garnet single crystal (hereinafter, RBiI).
G) (which has a large Faraday rotation coefficient) is laminated, and the desired Faraday rotation angle θF is obtained by adjusting the thickness of both films.
ここで、RIGは、ファラデー回転係数θＦ（deg/cm）
が小さいため、膜厚の変化に対するファラデー回転角θ
Ｆの大きな変化はなく、膜厚加工の許容幅が大きい。Here, RIG is the Faraday rotation coefficient θF (deg / cm)
Is small, the Faraday rotation angle θ with respect to the change in film thickness
There is no large change in F, and the allowable width of the film thickness processing is large.
従って、本発明に係る磁気光学素子のファラデー回転
角度θＦを精密に加工する必要がある場合にはRIG側を
加工する。これにより、ファラデー回転角θＦの微調整
加工が容易になる。Therefore, when it is necessary to precisely process the Faraday rotation angle θF of the magneto-optical element according to the present invention, the RIG side is processed. This facilitates fine adjustment of the Faraday rotation angle θF.
《実 施 例》 以下、本発明の好適な実施例を添付図面を参照して詳
述する。<< Embodiment >> Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
実施例1. 第１図（Ａ）に示す非磁性ガーネット単結晶基板たる
CaMsZr置換GGG基板１上に、先ず、ファラデー回転係数
θＦが250deg/cmのRIG［（TbLa）３（FeAl）5O12］２
を、LPE法により100μｍ育成させた（同図（Ｂ）参
照）。Example 1 A non-magnetic garnet single crystal substrate shown in FIG.
First, a RIG [(TbLa) 3 (FeAl) 5 O 12 ] 2 having a Faraday rotation coefficient θF of 250 deg / cm on a CaMsZr-substituted GGG substrate 1.
Was grown to 100 μm by the LPE method (see FIG. 1B).
このRIG2は表面が鏡面になっていたので、何らの加工
を施さず、そのままこの上にファラデー回転係数θF2が
−1500deg/cmのRBiIG（（TbLuBi）3FesO12）３を、LPE
法により307μｍ育成させた（同図（Ｃ）参照）。Since this RIG2 had a mirror-finished surface, it was not subjected to any processing, and RBiIG ((TbLuBi) 3 FesO 12 ) 3 having a Faraday rotation coefficient θF2 of −1500 deg / cm was placed on this RIG2 without any processing.
307 μm was grown by the method (see FIG. 3C).
次に、CaMsZr置換GGG基板１を除去した（同図（Ｄ）
参照）。このようにして本発明に係る磁気光学素子が製
造される。Next, the CaMsZr-substituted GGG substrate 1 was removed (FIG. 3D).
reference). Thus, the magneto-optical element according to the present invention is manufactured.
この状態で磁気光学素子のファラデー回転角度θＦを
測定したところ−43.5度であったため、RIG2側を切削加
工し、RIG2の膜厚を調整することより、θＦを45度にし
た。この磁気光学素子の波長依存性，温度依存性は、RB
iIG単独のものに比し、何ら損色なかった。In this state, the Faraday rotation angle θF of the magneto-optical element was measured to be −43.5 degrees. Therefore, the RIG2 side was cut and the film thickness of RIG2 was adjusted to set θF to 45 degrees. The wavelength dependence and temperature dependence of this magneto-optical element are RB
There was no discoloration compared to the iIG alone.
なお、この実施例においては、RBiIGは、膜厚が１μ
ｍ変化すると、ファラデー回転角度θF2は0.15度変化す
る。従って、前述したようにRBiIG側の膜厚調整により
磁気光学素子のファラデー回転角度θＦの精度を±0.5
度にしようとすると、膜厚の加工精度の許容幅を±3.3
μｍと極く狭くしなければならない。In this embodiment, RBiIG has a thickness of 1 μm.
m, the Faraday rotation angle θF2 changes by 0.15 degrees. Therefore, as described above, by adjusting the film thickness on the RBiIG side, the accuracy of the Faraday rotation angle θF of the magneto-optical element can be adjusted by ± 0.5.
If you try to adjust the thickness, the tolerance of processing accuracy of film thickness is ± 3.3
It must be as narrow as μm.
これに対し、RIG2は、膜厚１μｍの変化に対し、ファ
ラデー回転角度θF1の変化は0.025度と小さい。従っ
て、θＦの加工精度±0.5度に対する膜厚加工精度の許
容幅は±20μｍと、RIG2の加工精度±3.3μｍの約６倍
も広い。On the other hand, in the case of RIG2, the change in the Faraday rotation angle θF1 is as small as 0.025 degrees with respect to the change in the film thickness of 1 μm. Therefore, the allowable range of the film thickness processing accuracy with respect to the θF processing accuracy of ± 0.5 degrees is ± 20 μm, which is about six times wider than the RIG2 processing accuracy of ± 3.3 μm.
故に、この実施例では磁気光学素子のファラデー回転
角度θＦの高精度での調整を容易な加工技術により行う
ことができる。Therefore, in this embodiment, the Faraday rotation angle θF of the magneto-optical element can be adjusted with high accuracy by a simple processing technique.
なお、粗調整をするにはRBiIG3側を研削加工してもよ
い。It should be noted that the RBiIG3 side may be ground for rough adjustment.
実施例2. 実施例１において、RIGを（YLa）3Fe5O12（ファラデ
ー回転係数θF1が220deg/cm）、RBiIGを（GdLuBi）3Fe5
O12（ファラデー回転係数θF2が1600deg/cm）を用いる
以外は、実施例１と同様にしてファラデー回転角度θF4
5度の磁気光学素子を調整した。この磁気光学素子の波
長依存性，温度損色はなかった。Example 2. In Example 1, RIG was (YLa) 3 Fe 5 O 12 (Faraday rotation coefficient θF1 was 220 deg / cm), and RBiIG was (GdLuBi) 3 Fe 5
Except for using O 12 (Faraday rotation coefficient θF2 is 1600 deg / cm), the Faraday rotation angle θF4
The 5 degree magneto-optical element was adjusted. There was no wavelength dependence and no color loss of this magneto-optical element.
この実施例のRIGの加工精度の許容幅は、RBiIGのそれ
よりも７倍も広いため、容易な加工技術で高精度の調整
ができる。Since the allowable range of the processing accuracy of the RIG of this embodiment is seven times wider than that of the RBiIG, high-precision adjustment can be performed with an easy processing technique.
なお、本発明に係る磁気光学素子を製造するには、必
ずしも上記した方法の実施例に限られることなく、例え
ばCaMgZr置換GGG基板上にまずRBiIGを生長させ、ついで
そのRBiIG上にRIGを生長させるようにしてもよい。その
場合にも、ファラデー回転角度の微調整はRIG側を所定
厚さ切削加工することにより行うが、CaMgZr置換GGG基
板は必ずしも除去する必要はない。Incidentally, in order to manufacture the magneto-optical element according to the present invention, it is not necessarily limited to the embodiment of the method described above, for example, first growing RBiIG on a CaMgZr-substituted GGG substrate, and then growing RIG on the RBiIG. You may do so. In this case as well, the fine adjustment of the Faraday rotation angle is performed by cutting the RIG side to a predetermined thickness, but the CaMgZr-substituted GGG substrate does not necessarily need to be removed.
なお、本発明者らの知得したところによれば、上記RI
Gのファラデー回転係数θF1は、250deg/cm以下とするの
が好ましい。すなわち、これより大きいと膜厚加工の許
容幅が小さくなるからである。According to the knowledge of the present inventors, the above RI
The Faraday rotation coefficient θF1 of G is preferably set to 250 deg / cm or less. That is, if it is larger than this, the allowable width of the film thickness processing becomes smaller.
また、RBiIGのファラデー回転係数θF2は1500deg/cm
以上とするのが好ましい。これは、300μｍ程度の薄膜
で45度程度のファラデー回転角度θＦを持つ磁気光学素
子を得るためであり、θF2がこれより小さいと、膜厚を
厚くする必要が生じ、製造コストの増大、デバイスの大
型化を招くからである。The Faraday rotation coefficient θF2 of RBiIG is 1500 deg / cm
It is preferable to make the above. This is to obtain a magneto-optical element having a Faraday rotation angle θF of about 45 degrees with a thin film of about 300 μm. If θF2 is smaller than this, it is necessary to increase the film thickness, thereby increasing the manufacturing cost and increasing the device This is because the size is increased.
さらにまた、LPE法でRIGを育成させる際の膜厚を100
μｍ以下とするのが好ましい。これは、100μｍ以上の
膜厚とすると、膜表面が荒れるため、RBiIGの育成に先
立ってRIGの表面を研磨し鏡面加工を施す必要がある
が、100μｍ以下の膜厚では、このような加工は不要だ
からである。Furthermore, the film thickness when growing RIG by the LPE method is 100
It is preferably set to be not more than μm. This is because if the film thickness is 100 μm or more, the film surface becomes rough, so it is necessary to polish the RIG surface and perform mirror finishing prior to the growth of RBiIG. It is unnecessary.
《発明の効果》 以上詳述したように、本発明によれば、膜厚の加工許
容幅の大きいRIG側の膜厚を調整することにより磁気光
学素子のファラデー回転角度を調整するため、容易な加
工技術で高精度でのファラデー回転角度の調整を行なう
ことができる。この結果、加工コストが大幅に低減す
る。<< Effects of the Invention >> As described in detail above, according to the present invention, the Faraday rotation angle of the magneto-optical element is adjusted by adjusting the film thickness on the RIG side where the allowable processing width of the film thickness is large. The Faraday rotation angle can be adjusted with high precision by the processing technology. As a result, processing costs are significantly reduced.
特に、量産化の際にロッド毎に膜厚が異なる場合に
も、容易な加工技術でファラデー回転角度を高精度で調
整することができるため、製造・加工コストが著しく低
減する。In particular, even when the film thickness is different for each rod during mass production, the Faraday rotation angle can be adjusted with high precision by a simple processing technique, so that manufacturing and processing costs are significantly reduced.
以上により、RBiIGのBiの置換量を多くして、ある程
度大きなファラデー回転係数θＦ（deg/cm）を有するRB
iIGを用いることができるため、製造コストの大幅な低
減及びデバイスの大幅な小型化をも図ることができる。As described above, the replacement amount of Bi in RBiIG is increased, and the RB having a somewhat large Faraday rotation coefficient θF (deg / cm) is obtained.
Since the iIG can be used, the manufacturing cost can be significantly reduced and the device can be significantly reduced in size.
第１図は本発明に係る製造方法の好適な実施例を示す図
である。 １……GGG基板（非磁性ガーネット単結晶基板） ２……RIG（Bi非置換磁性ガーネット単結晶） ３……RBiIG（Bi置換磁性ガーネット単結晶）FIG. 1 is a view showing a preferred embodiment of the manufacturing method according to the present invention. 1. GGG substrate (non-magnetic garnet single crystal substrate) 2. RIG (Bi-substituted magnetic garnet single crystal) 3. RBiIG (Bi-substituted magnetic garnet single crystal)
Claims (2)
置換磁性ガーネット単結晶が積層されてなることを特徴
とする磁気光学素子。1. Bi-substituted magnetic garnet single crystal has Bi
A magneto-optical element comprising a substitution magnetic garnet single crystal laminated.
磁性ガーネット単結晶を液相エピタキシャル法により育
成させ、ついでそのBi非置換単結晶上にBi置換磁性ガー
ネット単結晶を液相エピタキシャル法により育成させた
後、少なくとも前記非磁性ガーネット単結晶基板と、Bi
非置換単結晶の一部を除去することを特徴とする磁気光
学素子の製造方法。2. A Bi-substituted magnetic garnet single crystal is grown on a non-magnetic garnet single crystal substrate by liquid phase epitaxy, and a Bi-substituted magnetic garnet single crystal is grown on the Bi non-substituted single crystal by liquid phase epitaxy. After growing, at least the non-magnetic garnet single crystal substrate, Bi
A method for manufacturing a magneto-optical element, comprising removing a part of an unsubstituted single crystal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29217689A JP2799011B2 (en) | 1989-11-13 | 1989-11-13 | Magneto-optical element and method of manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29217689A JP2799011B2 (en) | 1989-11-13 | 1989-11-13 | Magneto-optical element and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03154307A JPH03154307A (en) | 1991-07-02 |
| JP2799011B2 true JP2799011B2 (en) | 1998-09-17 |
Family
ID=17778546
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29217689A Expired - Fee Related JP2799011B2 (en) | 1989-11-13 | 1989-11-13 | Magneto-optical element and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2799011B2 (en) |
-
1989
- 1989-11-13 JP JP29217689A patent/JP2799011B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03154307A (en) | 1991-07-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4547754A (en) | Ferromagnetic resonator | |
| CA1127054A (en) | Temperature-stabilized low-loss ferrite films | |
| EP1162494B1 (en) | Faraday rotation angle varying device | |
| JP2799011B2 (en) | Magneto-optical element and method of manufacturing the same | |
| JP2786078B2 (en) | Faraday rotator and optical isolator | |
| US4269651A (en) | Process for preparing temperature-stabilized low-loss ferrite films | |
| US6491753B2 (en) | Method for the growing of single crystals | |
| US5701108A (en) | Magnetostatic wave device with a magnetic field applied parallel to an axis of easy magnetization | |
| EP0814560B1 (en) | Magnetostatic wave device | |
| KR100235766B1 (en) | A method for reducing insertion loss and ripple of a magnetostatic wave device | |
| JPH08165197A (en) | Method for manufacturing garnet magnetic oxide single crystal and magnetostatic wave device | |
| US4555374A (en) | Method of manufacturing a disc resonator | |
| US5135818A (en) | Thin soft magnetic film and method of manufacturing the same | |
| JPS61113026A (en) | Medium for magnetooptic element | |
| JPH07130539A (en) | Surface magnetostatic wave device | |
| CHEN | Magnetic resonance in amorphous bubble films[Ph. D. Thesis] | |
| US4131987A (en) | Method of producing a microwave filter comprising a body of gyromagnetic material and a source of a prepolarizing magnetic field whose resonant frequency is a predetermined function of the temperature | |
| Teter et al. | Anisotropic magnetostriction in Tb sub (0. 27) Dy sub (0. 73) Fe sub (1. 95). | |
| SU1116460A1 (en) | Process for manufacturing information medium with strip magnetic domains | |
| JP2794306B2 (en) | Magnetic garnet material and Faraday rotating element | |
| JP3089741B2 (en) | Materials for magnetostatic wave devices | |
| JPS62149055A (en) | Magnetooptic element | |
| JP2742537B2 (en) | Magneto-optical thin film and method of manufacturing the same | |
| JP2000089165A (en) | Manufacturing method of magneto-optical element | |
| JPH01224722A (en) | Production of magneto-optical element |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |