JPH0348832A - Domain control method for nonlinear ferroelectric optical material - Google Patents
Domain control method for nonlinear ferroelectric optical materialInfo
- Publication number
- JPH0348832A JPH0348832A JP1184364A JP18436489A JPH0348832A JP H0348832 A JPH0348832 A JP H0348832A JP 1184364 A JP1184364 A JP 1184364A JP 18436489 A JP18436489 A JP 18436489A JP H0348832 A JPH0348832 A JP H0348832A
- Authority
- JP
- Japan
- Prior art keywords
- optical material
- domain
- thickness direction
- nonlinear
- heating
- 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.)
- Pending
Links
- 239000000463 material Substances 0.000 title claims abstract description 55
- 230000003287 optical effect Effects 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims description 21
- 238000010438 heat treatment Methods 0.000 claims abstract description 24
- 239000006096 absorbing agent Substances 0.000 claims abstract description 21
- 230000000737 periodic effect Effects 0.000 abstract description 11
- 239000013078 crystal Substances 0.000 abstract description 10
- 239000000758 substrate Substances 0.000 abstract description 6
- 230000000694 effects Effects 0.000 abstract description 5
- 230000005466 cherenkov radiation Effects 0.000 abstract description 4
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 abstract description 4
- 230000010287 polarization Effects 0.000 abstract description 4
- 229910052697 platinum Inorganic materials 0.000 abstract description 3
- 238000009792 diffusion process Methods 0.000 abstract description 2
- 239000007772 electrode material Substances 0.000 abstract description 2
- 230000015556 catabolic process Effects 0.000 abstract 1
- 238000006731 degradation reaction Methods 0.000 abstract 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 5
- 239000012212 insulator Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 239000003779 heat-resistant material Substances 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000005616 pyroelectricity Effects 0.000 description 1
- 229940005657 pyrophosphoric acid Drugs 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 229910052594 sapphire Inorganic materials 0.000 description 1
- 239000010980 sapphire Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/37—Non-linear optics for second-harmonic generation
- G02F1/377—Non-linear optics for second-harmonic generation in an optical waveguide structure
- G02F1/3775—Non-linear optics for second-harmonic generation in an optical waveguide structure with a periodic structure, e.g. domain inversion, for quasi-phase-matching [QPM]
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/355—Non-linear optics characterised by the materials used
- G02F1/3558—Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/35—Non-linear optics
- G02F1/353—Frequency conversion, i.e. wherein a light beam is generated with frequency components different from those of the incident light beams
- G02F1/3544—Particular phase matching techniques
- G02F1/3548—Quasi phase matching [QPM], e.g. using a periodic domain inverted structure
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、例えば光第２高調波発生素子（以下ＳＨＧ素
子という）における周期ドメイン反転構造部の形成に適
用して好適な非線形強誘電体光学材料に対するドメイン
制御方法に係わる。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a nonlinear ferroelectric material suitable for forming a periodic domain inversion structure in, for example, an optical second harmonic generation device (hereinafter referred to as an SHG device). It relates to a domain control method for optical materials.
本発明は、非線形強誘電体光学材料に対するドメイン制
御方法に係わり、シングルドメイン化された非線形強誘
電体光学材料体の主面に所要のパターンをもって非線形
強誘電体光学材料体に対する加熱用電磁波の吸収体また
は反射体を配置し上記電磁波によって非線形強誘電体光
学材料体を上記吸収体または反射体のパターンに対応す
るパターンをもって局部的に高速昇温・降温をなして上
記主面に局部的にドメイン反転部を形成するようにして
簡単な作業及び装置によって確実に非線形強誘電体光学
材料体にドメイン反転構造部を形成する。The present invention relates to a domain control method for a nonlinear ferroelectric optical material, in which a required pattern is formed on the main surface of a single domain nonlinear ferroelectric optical material to absorb heating electromagnetic waves for the nonlinear ferroelectric optical material. A nonlinear ferroelectric optical material body is heated and cooled locally in a pattern corresponding to the pattern of the absorber or reflector by the electromagnetic waves, and a domain is locally formed on the main surface. By forming an inversion part, a domain inversion structure part is reliably formed in a nonlinear ferroelectric optical material body using simple operations and equipment.
チェレンコフ放射を用いたＳＨＧ素子の提案がなされて
いる（例えば呑口、山車：応用物理５６．１６３７（１
９８７） 参照）。しかしながら、このＳＨＧ素子にお
いてはビームの放射方向が基板内方向であり、ビームス
ポット形状も例えば三日月状スポットという特異な形状
をなし、実際の使用においての問照点が存在する。これ
に対してその導波路の構造を、コヒーレント長の奇数倍
にドメインを反転させた周期的ドメイン反転構造とする
ことによって高効率で円形もしくは楕円形のビームスポ
ット形状の出力を得るようにしたＳＨＧ素子の提案がな
された（伊藤弘昌、張英海他、第４９回応用物理学会講
演会予稿集９１９ （１９８８） 参照）。SHG devices using Cherenkov radiation have been proposed (for example, Noguchi, Dashi: Applied Physics 56.1637 (1)
987). However, in this SHG element, the radiation direction of the beam is toward the inside of the substrate, and the beam spot also has a unique shape, for example, a crescent-shaped spot, which poses questions in actual use. On the other hand, by making the waveguide structure a periodic domain inversion structure in which the domain is inverted to an odd multiple of the coherent length, SHG is able to obtain a highly efficient output with a circular or elliptical beam spot shape. A proposal for an element was made (see Hiromasa Ito, Yinghai Zhang, et al., Proceedings of the 49th Japan Society of Applied Physics Conference 919 (1988)).
そして、ドメイン反転を行わしめる方法としては、結晶
引上げ時に電流制御等を行う方法がある（Ｄ、Ｆｅｎｇ
、 Ｎ、Ｂ、Ｍｉｎｇ、 Ｊ、Ｆ、Ｈｏｎｇ、他、Ａｐ
ｐｌｉｅｄ Ｐｌｙｓｉｃｓ Ｌｅｔｔｅｒｓ、 ３７
．６０７（１９８０）、 Ｋ、Ｎａ５ｓａｕ、 ）１，
１゜Ｌｅｖｉｎｓｔｅｉｎ、 Ｇ、Ｈ，Ｌｏｉａｃｏｎ
ｏ、 Ａｐｐｌｉｅｄ ＰｈｙｓｉｃｓＬｅｔｔｅｒｓ
６．２２８（１９６５）、＾、Ｆｅ１ｓｓｔ、 Ｐ、
Ｋｏｉｄｌ。As a method for performing domain inversion, there is a method of controlling current during crystal pulling (D, Feng
, N.B., Ming, J.F., Hong, et al., Ap.
Plied Physics Letters, 37
．． 607 (1980), K. Na5sau, )1,
1゜Levinstein, G.H., Loiacon
o, Applied Physics Letters
6.228 (1965), ^, Fe1sst, P.
Koidl.
Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃｓ Ｌｅｔｔｅｒｓ ４
７． １１２５（１９８５）参照）しかしながら、この
ような方法による場合、大規模な装置が必要となるのみ
ならず、ドメイン形成の制御が難しいという問題点があ
る。Applied Physics Letters 4
7. 1125 (1985)) However, such a method not only requires a large-scale apparatus, but also has problems in that it is difficult to control domain formation.
また、ドメイン反転の他の方法としては、例えばＴｉを
拡散させる方法が考えられるが、この場合ドメイン反転
した部分の屈折率が変化しＳＨ波のビームが多数本にな
るという問題点がある。Further, as another method of domain inversion, for example, a method of diffusing Ti may be considered, but in this case, there is a problem that the refractive index of the domain inverted portion changes, resulting in a large number of SH wave beams.
本発明は、簡単な装置で、すなわち大規模な装置を必要
とすることなく、また簡単な作業で、かつドメイン反転
部の屈折率変化を招来することがなく高精度に正確に微
細パターンの周期的ドメインの反転構造を形成すること
ができるようにすることを目的とする。The present invention is a simple device, that is, without the need for a large-scale device, by a simple operation, and without causing a change in the refractive index of the domain inversion region. The purpose is to make it possible to form an inverted structure of a target domain.
尚、このような目的をもって先に本出願人による特願平
１−１１１２７１号特許出願において非線形強返電体光
学材料に対するドメイン制御方法の提案がなされた。こ
の方法においては、シングルドメイン化された非線形強
誘電体光学材料体を挟んでその相対向する両主面に対向
電極を配置し、その少なくとも一方を周期的ドメイン反
転構造に対応するパターンに形成して両電極間に直流電
圧を印加することによって局部的にドメイン反転部を形
成して周期的ドメイン反転構造を形成するものである。For this purpose, a domain control method for a nonlinear ferroelectric optical material was previously proposed in Japanese Patent Application No. 1-111271 filed by the present applicant. In this method, counter electrodes are placed on both opposing principal surfaces of a single-domain nonlinear ferroelectric optical material, and at least one of them is formed into a pattern corresponding to a periodic domain inversion structure. By applying a DC voltage between both electrodes, domain inversion parts are locally formed, thereby forming a periodic domain inversion structure.
この方法による場合、その非線形強誘電体光学材料結晶
基板に直接電極を被着するとか、直接電極を接触させて
、対向電極間に電圧印加を行うことから、その電圧印加
に際して結晶基板に電流が流れることによってこの非線
形強誘電体光学材料体の結晶に損傷を与えるという危険
性がある。In this method, electrodes are directly attached to the nonlinear ferroelectric optical material crystal substrate or electrodes are brought into direct contact with each other and a voltage is applied between opposing electrodes, so that when the voltage is applied, a current is applied to the crystal substrate. There is a risk of damaging the crystal of this nonlinear ferroelectric optical material by flowing.
さらにこのドメイン反転作業に際しての電圧印加の際に
この材料体の抗電界を下げるために行われる高温加熱に
よって非線形光学材料体の構成材料原子と電極となる原
子とが互いに拡散し光学材料体の純度が損なわれる危険
性がある等の不都合がある。Furthermore, when voltage is applied during this domain inversion process, high-temperature heating is performed to lower the coercive electric field of this material body, which causes the constituent material atoms of the nonlinear optical material body and the atoms that will become the electrodes to diffuse into each other, thereby increasing the purity of the optical material body. There are inconveniences such as the risk of damage.
本発明は、このような結晶の損傷あるいは純度の低下等
の課題の解決をはかることを目的とする。The present invention aims to solve problems such as damage to crystals and reduction in purity.
本発明においては、第１図に示すようにシングルドメイ
ン化された非線形強誘電体光学材料体（１）の−主面（
１ａ）に、所要のパターンのすなわち最終的にこの材料
体（１）の主面（１ａ）に形成するべきドメイン反転構
造部のパターンに対応するパターン、具体的には平行配
列パターンをもって、非線形強誘電体光学材料体（１）
に対する加熱用電磁波例えば加熱ヒータからの熱線ある
いは加熱用のレーザー光等の加熱光、粒子線等の電磁波
に対しての吸収体または反射体（２）を配置し、上述の
電磁波を上述の吸収体または反射体（２）上より照射し
て、このパターンに応じたパターンの加熱を非線形強誘
電体光学材料体（１）に対して行って第３図Ａに示すよ
うにこのパターンに対応するドメイン反転部（３）を局
部的に形成する。In the present invention, as shown in FIG. 1, the -principal surface (
1a), a pattern corresponding to the required pattern, that is, a pattern of domain inversion structures to be finally formed on the main surface (1a) of this material body (1), specifically a parallel arrangement pattern, is used to generate a nonlinear Dielectric optical material (1)
An absorber or a reflector (2) is arranged for heating electromagnetic waves such as heat rays from a heating heater, heating light such as heating laser light, particle beams, etc., and the above-mentioned electromagnetic waves are absorbed by the above-mentioned absorber. Alternatively, the nonlinear ferroelectric optical material body (1) is heated in a pattern corresponding to this pattern by irradiating it from above the reflector (2) to form domains corresponding to this pattern as shown in FIG. 3A. A reversal portion (3) is formed locally.
本発明方法では、非線形強誘電体光学材料体（１）の主
面（１ａ）に対してその加熱用の電磁波に対しての吸収
体または反射体（２）を配置することによって非線形強
誘電体光学材料体（１）が局部的に加熱され、この加熱
によって分極反転が生じ易くなる部分が、この局部的高
速昇温降温の温度変化を５℃／分以上とすると、焦電効
果によって誘起された電荷による電圧により効果的に分
極反転が生じドメイン反転が生ずる。In the method of the present invention, by arranging an absorber or reflector (2) for electromagnetic waves for heating on the main surface (1a) of the nonlinear ferroelectric optical material body (1), the nonlinear ferroelectric optical material body (1) is The optical material body (1) is locally heated, and the part where polarization reversal is likely to occur due to this heating is induced by the pyroelectric effect when the temperature change of this local high-speed temperature increase and decrease is 5°C/min or more. The voltage generated by the accumulated charges effectively causes polarization inversion, resulting in domain inversion.
本発明方法を周期的ドメイン反転構造部を有するチェレ
ンコフ放射型ＳＨＧ素子を得る場合についての一例を説
明する。An example of the method of the present invention for obtaining a Cerenkov radiation type SHG element having a periodic domain inversion structure will be described.
この場合、非線形係数の大きいニオブ酸リチウム（ＬＩ
Ｎｋ）Ｏ＊）結晶の厚さ方向にＣ釉を有するいわゆる２
基板より成り、例えば主面（１ａ）側を＋６面とする。In this case, lithium niobate (LI), which has a large nonlinear coefficient,
Nk)O*)So-called 2 with C glaze in the thickness direction of the crystal
It is made of a substrate, and the main surface (1a) side is, for example, the +6 surface.
すなわち厚さ方向にＣ軸（２軸）を有するシングルドメ
イン化された非線形強誘電体光学材料体（１）を用意す
る。この非線形強誘電体光学材料体（１）のシングルド
メイン化は、例えばそのキュリー温度以下の例えば１２
００℃程度まで昇温しでその厚さ方向に外部直流電圧を
全面的に印加することによって全面的にＣ軸を厚さ方向
に揃えたドメイン化を行うことができる。That is, a single domain nonlinear ferroelectric optical material body (1) having a C axis (two axes) in the thickness direction is prepared. This nonlinear ferroelectric optical material body (1) can be made into a single domain, for example, at a temperature below its Curie temperature of 12
By raising the temperature to about 00° C. and applying an external DC voltage to the entire surface in the thickness direction, it is possible to form domains with the C axis aligned in the thickness direction over the entire surface.
そして、本発明においては、この非線形強誘電体光学材
料体（１）の−主面（１ａ）に、これを加熱する例えば
熱線に対しての耐熱性の吸収体または反射体（２）例え
ば白金ｐｔを最林的に得る例えば東３図Ａに示すドメイ
ン反転部（３ａ）がストライブ状に所定のピッチをもっ
て平行配列する周期的ドメイン反射構造部（３）のパタ
ーンに応じてすなわち導波方向と直交する方向に所要の
幅及びピッチをもって平行にストライブ状に形成する。In the present invention, a heat-resistant absorber or reflector (2), for example, platinum, for heating the nonlinear ferroelectric optical material body (1) is attached to the main surface (1a) of the nonlinear ferroelectric optical material body (1). For example, according to the pattern of the periodic domain reflection structure (3) in which the domain inversion parts (3a) shown in Fig. 3A are arranged parallel to each other at a predetermined pitch in the form of stripes, that is, in the waveguide direction. They are formed in parallel stripes with the required width and pitch in the direction orthogonal to the .
この吸収体または反射体（２）は、耐熱性を存する例え
ば白金ｐｔの全面蒸着、フォトリソグラフィによる選択
的ウェットエツチングもしくはドライエツチングによっ
て形成し得る。This absorber or reflector (2) can be formed by full-surface vapor deposition of a heat-resistant material such as platinum PT, selective wet etching or dry etching using photolithography.
また、上述した例においては、吸収体または反射体（２
）を直接的に非線形強誘電体光学材料体（１）の主面（
１ａ）に被着形成した場合があるが、ある場合は、第２
図に示すようにＡ ｉ ２０．、 ＳｉＯ□等の耐熱性
絶縁体（４）を非線形強誘電体光学材料体（１）の主面
（１ａ）上に被着し、これの上に上述した吸収体または
反射体（２）を前述したと同様の手法によって被着する
こともできるし、あるいはドメイン反転構造部を形成す
る非線形強誘電体光学材料体（１）とは別体に用意した
＾ｌ ２０．、サファイア等の板体より成る絶縁体（４
）上に吸収体または反射体（２）を前述した手法によっ
て所要のパターンに被着形成し、この絶縁体（４）を介
して吸収体または反射体（２）を非線形強誘電体光学材
料体（１）の主面（１ａ）に衝合するように配置する。In addition, in the above-mentioned example, an absorber or a reflector (2
) directly on the main surface of the nonlinear ferroelectric optical material (1) (
1a), but in some cases, the second
As shown in the figure, A i 20. , A heat-resistant insulator (4) such as SiO It can be deposited by the same method as described above, or it can be prepared separately from the nonlinear ferroelectric optical material (1) that forms the domain inversion structure. 20. , an insulator made of a plate such as sapphire (4
), the absorber or reflector (2) is deposited in a desired pattern by the method described above, and the absorber or reflector (2) is formed on the nonlinear ferroelectric optical material through the insulator (4). (1) so as to abut against the main surface (1a).
このように吸収体または反射体〔２〕が配置された非線
形強誘電体光学材料体（１）を特に加熱用電磁波例えば
ランプあるいはヒータ等の発熱体よりの熱線、あるいは
レーザー光等の電磁波照射によって加熱する。The nonlinear ferroelectric optical material body (1) in which the absorber or reflector [2] is arranged in this manner is irradiated with heating electromagnetic waves, such as heat rays from a heating element such as a lamp or heater, or electromagnetic waves such as laser light. Heat.
第４図はこの加熱装置の一例の路線断面図を示す。（１
１）は石英管等よりなる炉心管で、この炉心管（１１）
内に、耐熱性の例えば石英より成る支持体り１２）によ
って、前述した吸収体または反射体（２）を有する非線
形強誘電体光学材料体（１）を、その吸収体または反射
体（２〕を有する面（１ａ）とは反対側の面で受けて配
置する。り１３）は、例えば炉心管（１１）の外周に配
されたヒータ・ランプ等の加熱手段で、これよりの熱線
を材料体（１）に照射するようになされる。このように
すると吸収体または反射体（２）の配置部において電磁
波、この場合は熱線が効率良く吸収または反射排除され
この配置部が他部に比し高温に加熱もしくは非加熱状態
となって非線形強誘電体光学材料体（１）の主面（１ａ
）に吸収体または反射体（２）のパターンに応じた加熱
または非加熱分布が生じる。例えば上述したｐｔパター
ンに形成する場合はこれが電磁波（この例では熱線）の
反射層として作用する二とによってこのＰｔパターンに
よる反射層がない部分の材料体（１）の表面（１ａ）が
選択的に加熱される。このときの局部的加熱は１０００
〜１２００℃に選定することが望ましく、また、このと
きの昇温または加熱停止後の降温レートを５℃／分以上
とすれば、非線形誘電体光学材料体（１）のニオブ酸リ
チウムの焦電効果によって発生する誘起電荷を効果的に
利用することができ、これによる分極反転、したがって
ドメイン反転を得ることができる。FIG. 4 shows a line sectional view of an example of this heating device. (1
1) is a furnace core tube made of quartz tube etc. This furnace core tube (11)
The nonlinear ferroelectric optical material body (1) having the aforementioned absorber or reflector (2) is attached to the absorber or reflector (2) by a heat-resistant support 12) made of, for example, quartz. 13) is a heating means such as a heater lamp arranged around the outer periphery of the furnace core tube (11), and the hot rays from this are used to heat the material. It is made to irradiate the body (1). In this way, electromagnetic waves, in this case heat rays, are efficiently absorbed or reflected and eliminated in the part where the absorber or reflector (2) is arranged, and this part is heated to a higher temperature than other parts or is not heated, resulting in a non-linear The main surface (1a) of the ferroelectric optical material body (1)
), a heating or non-heating distribution occurs depending on the pattern of the absorber or reflector (2). For example, when forming the above-mentioned PT pattern, this acts as a reflective layer for electromagnetic waves (heat rays in this example), so that the surface (1a) of the material body (1) where there is no reflective layer due to this Pt pattern is selectively is heated to. The local heating at this time is 1000
It is desirable to select a temperature of ~1200°C, and if the temperature increase or cooling rate after heating is 5°C/min or more, the pyroelectricity of the lithium niobate of the nonlinear dielectric optical material (1) The induced charge generated by the effect can be effectively utilized, and thereby polarization inversion and therefore domain inversion can be obtained.
このようにして第３図Ａに示すように、ドメイン反転部
（３ａ）が配列された周期的ドメイン反転構造部（３）
が形成された非線形強誘電体光学材料体（１）を得るこ
とができる。In this way, as shown in FIG. 3A, a periodic domain inversion structure (3) in which domain inversion parts (3a) are arranged is formed.
A nonlinear ferroelectric optical material body (1) in which is formed can be obtained.
そして例えば第３図Ｂ、に示すように、この周期的ドメ
イン反転構造Ｂ（３）を有する材料体（１）の主面（１
ａ）側に例えばピロリン酸を塗布後熱拡散させたり、或
いは例えばホットリン酸に浸してプロトン置換によって
屈折率が材料体（１）に比して大とされた光導波路（５
）を形成する。このようにすると周期的ドメイン反転構
造部（３）が光導波路（５）内に入り込んだ構造が得ら
れるが、他の例としては第３図８２ に示すように、周
期的ドメイン反転構造部（３）を有する材料体（１）の
−主面上（１ａ）に光導波路（５）を、基本波に対して
吸収率が低く材料体（１）より高屈折率材料層の非線形
ないしは、線形の例えばＴａ２Ｏ。For example, as shown in FIG. 3B, the main surface (1) of the material body (1) having this periodic domain inversion structure B (3)
An optical waveguide (5) whose refractive index is made larger than that of the material body (1) by applying, for example, pyrophosphoric acid on the a) side and then thermally diffusing it, or by soaking it in, for example, hot phosphoric acid and replacing protons.
) to form. In this way, a structure in which the periodic domain inversion structure (3) enters the optical waveguide (5) can be obtained, but as another example, as shown in FIG. 3) on the main surface (1a) of the material body (1) having a non-linear or linear For example, Ta2O.
にＴｌＯ２がＴｉとＴａの和に対するＴｉの割合Ｔｉ／
（Ｔｉ ＋Ｔａ）（原子％）がＯ＜Ｔｉ／（Ｔｉ ＋Ｔ
ａ） ＜６０ （原子％）となるようにドープされた材
料層、あるいはその他室化シリコン、二酸化チタン、セ
レン化砒素ガラス、硫化亜鉛、酸化亜鉛等の蒸着による
堆積、エピタキシャル成長等によって形成し得る。, TlO2 is the ratio of Ti to the sum of Ti and Ta, Ti/
(Ti + Ta) (atomic %) is O<Ti/(Ti +T
a) A layer of material doped to <60 (at.
このようにして平行ストライブ状の周期ドメイン反転構
造部（３）が導波方向を横切って形成された目的とする
ＳＨＧ素子を得る。In this way, a target SHG element is obtained in which parallel striped periodic domain inversion structures (3) are formed across the waveguide direction.
尚、上述した加熱装置によっての加熱に際し、非線形強
誘電体光学材料体（１）は、成る程度全体的にも所要の
温度に加熱しておくことが望ましく、このために、支持
体（１２）としては、前述の加熱用の電磁波を成る程度
吸収する材料によって構成することができる。In addition, when heating with the above-mentioned heating device, it is desirable that the nonlinear ferroelectric optical material body (1) be heated to a required temperature as a whole, and for this purpose, the support body (12) As such, it can be constructed of a material that absorbs the above-mentioned heating electromagnetic waves to some extent.
上述した本発明方法によれば、ドメイン反転構造部を形
成すべき非線形強誘電体光学材料体（１）の−主面（１
ａ）側にこれを加熱する電磁波の吸収体または反射体（
２）を配置するのみで回答電圧印加を行う必要がないこ
とによって電圧印加に伴う非線形強誘電体光学材料体（
１）に電流が流れることによる結晶の破損や電極材料と
の相互拡散による純度の低下等が回避され特性の安定し
たＳＨＧ素子を得ることができる。According to the method of the present invention described above, the main surface (1) of the nonlinear ferroelectric optical material (1) in which the domain inversion structure is to be formed is
a) An absorber or reflector of electromagnetic waves that heats it (
2) There is no need to apply a response voltage just by arranging the nonlinear ferroelectric optical material (
1) It is possible to avoid damage to the crystal due to the flow of current and a decrease in purity due to interdiffusion with the electrode material, thereby making it possible to obtain an SHG element with stable characteristics.
またこの電圧印加に伴う複雑な装置を構成する必要がな
いことから簡単な作業で安定してドメイン反転構造部を
構成することができる。Furthermore, since there is no need to construct a complicated device for applying this voltage, the domain inversion structure can be stably constructed with simple operations.
そして反射体または吸収体（２）のパターンは通常の半
導体製造技術に適用されるフォトリソグラフィによる高
精度な微細パターンが形成できることによって、これに
対応して微細のドメイン反転部（３ａ）例えば周期的ド
メイン反転構造部（３）を高精度に形成することができ
る。また、このドメイン反転構造部（３）の形成に当た
って上述したＴ１等の拡散によることがないことから基
板の屈折率変化を伴わず優れた特性のＳＨＧ素子を得る
ことができるなど実用に供してその利益は大である。The pattern of the reflector or absorber (2) can be formed by forming fine domain inversion parts (3a), for example, periodically, because a highly accurate fine pattern can be formed by photolithography, which is applied to ordinary semiconductor manufacturing technology. The domain inversion structure (3) can be formed with high precision. In addition, since the formation of this domain inversion structure (3) does not involve the diffusion of T1, etc., as described above, it is possible to obtain an SHG element with excellent characteristics without causing a change in the refractive index of the substrate. The profits are huge.
第１図及び第２図はそれぞれ本発明方法の各側の説明に
供するドメイン反転制御方法の実施態様の説明図、第３
図は本発明方法をチェレンコフ放射型ＳＨ，Ｇ素子を得
る場合に適用する一例の各工程の路線的拡大断面図、第
４図は加熱装置の一例の路線的断面図である。
（１）は非線形強誘電体光学材料体、（２）は吸収体ま
たは反射体である。1 and 2 are explanatory diagrams of an embodiment of the domain inversion control method for explaining each side of the method of the present invention, and FIG.
The figure is an enlarged linear sectional view of each step of an example in which the method of the present invention is applied to obtain a Cerenkov radiation type SH, G element, and FIG. 4 is a linear sectional view of an example of a heating device. (1) is a nonlinear ferroelectric optical material body, and (2) is an absorber or reflector.
Claims (1)
主面に所要のパターンの上記非線形強誘電体光学材料体
に対する加熱用電磁波の吸収体または反射体を配置し、
上記電磁波により上記非線形強誘電体光学材料体を加熱
して上記吸収体または反射体のパターンに対応するパタ
ーンのドメイン反転部を局部的に形成することを特徴と
する非線形強誘電体光学材料に対するドメイン制御方法
。arranging an absorber or reflector of electromagnetic waves for heating the nonlinear ferroelectric optical material in a desired pattern on the main surface of the single-domain nonlinear ferroelectric optical material;
A domain for a nonlinear ferroelectric optical material characterized in that the nonlinear ferroelectric optical material is heated by the electromagnetic wave to locally form a domain inversion part of a pattern corresponding to the pattern of the absorber or reflector. Control method.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184364A JPH0348832A (en) | 1989-07-17 | 1989-07-17 | Domain control method for nonlinear ferroelectric optical material |
| EP90113467A EP0409104B1 (en) | 1989-05-18 | 1990-07-13 | Method of controlling the domain of a nonlinear ferroelectric optics substrate |
| DE69026766T DE69026766T2 (en) | 1989-05-18 | 1990-07-13 | Method for controlling the ferroelectric domains of a nonlinear optical substrate |
| KR1019900010872A KR100192989B1 (en) | 1989-05-18 | 1990-07-16 | Method of controlling the domain of a nonlinear ferroelectric optics substrate |
| US07/729,897 US5193023A (en) | 1989-05-18 | 1991-07-15 | Method of controlling the domain of a nonlinear ferroelectric optics substrate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1184364A JPH0348832A (en) | 1989-07-17 | 1989-07-17 | Domain control method for nonlinear ferroelectric optical material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0348832A true JPH0348832A (en) | 1991-03-01 |
Family
ID=16151942
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1184364A Pending JPH0348832A (en) | 1989-05-18 | 1989-07-17 | Domain control method for nonlinear ferroelectric optical material |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0348832A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03260635A (en) * | 1990-03-12 | 1991-11-20 | Fujitsu Ltd | Formation of partial polarization inversion region |
| US5410561A (en) * | 1992-08-26 | 1995-04-25 | Sony Corporation | Optical wavelength converter for obtaining wavelength conversion efficiency |
| US6334008B2 (en) | 1998-02-19 | 2001-12-25 | Nec Corporation | Optical circuit and method of fabricating the same |
-
1989
- 1989-07-17 JP JP1184364A patent/JPH0348832A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH03260635A (en) * | 1990-03-12 | 1991-11-20 | Fujitsu Ltd | Formation of partial polarization inversion region |
| US5410561A (en) * | 1992-08-26 | 1995-04-25 | Sony Corporation | Optical wavelength converter for obtaining wavelength conversion efficiency |
| US6334008B2 (en) | 1998-02-19 | 2001-12-25 | Nec Corporation | Optical circuit and method of fabricating the same |
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