JP2900576B2 - Harmonic generator - Google Patents
Harmonic generatorInfo
- Publication number
- JP2900576B2 JP2900576B2 JP27523790A JP27523790A JP2900576B2 JP 2900576 B2 JP2900576 B2 JP 2900576B2 JP 27523790 A JP27523790 A JP 27523790A JP 27523790 A JP27523790 A JP 27523790A JP 2900576 B2 JP2900576 B2 JP 2900576B2
- Authority
- JP
- Japan
- Prior art keywords
- fundamental wave
- nonlinear optical
- harmonic
- optical material
- optical axis
- 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
Landscapes
- Semiconductor Lasers (AREA)
Description
【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、半導体レーザ等の基本波発生用の光源と基
本波を高調波へ変換する非線形光学材料を備えた周波数
安定化された高調波発生装置に関するものである。The present invention relates to a frequency-stabilized harmonic having a light source for generating a fundamental wave such as a semiconductor laser and a nonlinear optical material for converting the fundamental wave to a harmonic. It relates to a generator.
［従来の技術］ 従来、たとえば基本波の光源として半導体レーザを用
い非線形光学材料によって第２高調波を発生する高調波
発生装置において、複数枚の共振用ミラーで構成された
共振器内に非線形光学材料を挿入して基本波を共振させ
変換効率を向上させていた。しかし、ミラー等の部品点
数が多いため装置が複雑で大きくなる、光軸調整が困難
である。温度変化や機械的振動の影響を受けやすく光軸
ずれを起し出力が不安定であるなどの、問題点があっ
た。2. Description of the Related Art Conventionally, for example, in a harmonic generator that generates a second harmonic using a nonlinear optical material using a semiconductor laser as a light source of a fundamental wave, a nonlinear optical element is provided in a resonator constituted by a plurality of resonance mirrors. By inserting a material, the fundamental wave resonates to improve the conversion efficiency. However, since the number of components such as mirrors is large, the device becomes complicated and large, and it is difficult to adjust the optical axis. There is a problem that the optical axis shifts easily due to temperature change and mechanical vibration, and the output is unstable.
［発明の解決しようとする課題］ 本発明は、従来知られていなかった高調波発生装置の
構成を新規に提供することを目的とするものであり、ま
た従来技術が有していた前述の欠点を解消しようとする
ものである。[Problem to be Solved by the Invention] An object of the present invention is to provide a new configuration of a harmonic generation device which has not been known in the related art. Is to be solved.
［課題を解決するための手段］ 本発明は前述の問題点を解決すべくなされたものであ
り、基本波発生用の光源と、基本波を波長変換し高調波
を発生する非線形光学材料とを備えた高調波発生装置に
おいて、該非線形光学材料の基本波の入射面と高調波の
出射面には基本波が非線形光学材料内で共振するよう光
学膜が設けられ、該非線形光学材料の形状は基本波がそ
の中でＶ字形の共振光路をとるように、基本波の入射面
は光軸に対して傾いた平面とされ高調波の出射面は光軸
に対して垂直な面を含む平面又は曲面とされ、さらに基
本波の反射面は光軸に対して垂直な面を含む平面又は曲
面とされていることを特徴とする高調波発生装置を提供
するものである。Means for Solving the Problems The present invention has been made to solve the above-described problems, and includes a light source for generating a fundamental wave and a nonlinear optical material that converts the wavelength of the fundamental wave to generate a harmonic. In the provided harmonic generator, an optical film is provided so that the fundamental wave resonates in the nonlinear optical material on the incident surface of the fundamental wave and the emission surface of the harmonic of the nonlinear optical material, and the shape of the nonlinear optical material is The incident surface of the fundamental wave is a plane inclined with respect to the optical axis so that the fundamental wave takes a V-shaped resonance optical path therein, and the emission surface of the harmonic wave is a plane including a plane perpendicular to the optical axis or It is another object of the present invention to provide a harmonic generator, wherein the harmonic generation device is a curved surface, and the reflection surface of the fundamental wave is a flat surface or a curved surface including a surface perpendicular to the optical axis.
以下、本発明の実施例に従って説明する。第１図に本
発明の基本的構成の側面図を示す。第１図において１は
半導体レーザ、２は集光用及びモードマッチング用のレ
ンズ、３はKNbO3結晶等の非線形光学材料、４はPZT素子
等の圧電素子である。非線形光学材料３は光の入・出射
面が平面および球面に光学研磨されており、半球形状の
共振器が形成されている。非線形光学材料３の平面側の
中心点から斜めに基本波を入射させることでＶ字共振
（後述するａ、ｂ及びｃの各面と基本波光軸との交点を
Ａ点、Ｂ点及びＣ点とすると、反射点であるＡ点を介
し、Ｂ点とＣ点との間で往復する）させ、また非線形光
学材料への基本波の入射面からの直接反射光が半導体レ
ーザ１に戻らないようにしている。非線形光学材料３の
光入・出射面である平面および球面には光学多層膜を付
けて、効率よく基本波が入射および共振し、高調波が出
射するようにされている。また、圧電素子４の印加電圧
を調整して非線形光学材料３の位置を微調整し、半導体
レーザへフィードバックする共振器からの光の位相制御
や共振状態の制御も行なうようにする。Hereinafter, the present invention will be described in accordance with embodiments. FIG. 1 shows a side view of the basic configuration of the present invention. In FIG. 1, 1 is a semiconductor laser, 2 is a lens for focusing and mode matching, 3 is a nonlinear optical material such as a KNbO 3 crystal, and 4 is a piezoelectric element such as a PZT element. The non-linear optical material 3 has optically polished flat and spherical optical input and output surfaces to form a hemispherical resonator. By making the fundamental wave incident obliquely from the center point of the non-linear optical material 3 on the plane side, V-shaped resonance (the intersections of the fundamental wave optical axis with the planes a, b and c to be described later are point A, point B and point C) Then, the laser beam reciprocates between the point B and the point C via the point A which is a reflection point), and the direct reflection light from the incident surface of the fundamental wave to the nonlinear optical material is not returned to the semiconductor laser 1. I have to. An optical multilayer film is provided on the plane and the spherical surface, which are the light entrance / exit surfaces of the nonlinear optical material 3, so that the fundamental wave enters and resonates efficiently, and harmonics exit. Further, the position of the nonlinear optical material 3 is finely adjusted by adjusting the voltage applied to the piezoelectric element 4 so as to control the phase of the light from the resonator fed back to the semiconductor laser and the resonance state.
非線形光学材料としては、KNbO3，LiNbO3，KTiOPO4，
KH4PO4等の非線形光学結晶、非線形光学ガラス、有機非
線形光学材料が用いられる。その形状としては、非線形
光学材料内でＶ字共振する形状であればよく、多面体等
の形状であってもよい。Ｖ字共振するためには、基本波
の入射面が光軸に対して傾斜しており、高調波の出射面
及び基本波の反射面が各々基本波の光軸に対して垂直な
面を含むような形状であればよい。すなわち、光軸と出
射面及び反射面との各交点における各接平面が光軸に対
して垂直であればよい。基本波の光源としては、半導体
レーザ、各種気体及び固体レーザが使用できるが、半導
体レーザを使用するのが小型化や周波数制御の容易さの
点において好ましい。また、基本波の光源として半導体
レーザを使用する場合、その発振周波数を非線形光学材
料の共振器の共振周波数にロックし安定化するために非
線形光学材料内の共振光を一部半導体レーザへ戻す際
に、半導体レーザからの光と戻り光との間の位相の制御
を行なうための位置調整手段を設けるのが好ましい。そ
の位置調整手段としては前述の圧電素子、その他ねじ、
歯車、レール等を組合せた機械的手段を用いてもよい。As nonlinear optical materials, KNbO 3 , LiNbO 3 , KTiOPO 4 ,
A nonlinear optical crystal such as KH 4 PO 4 , a nonlinear optical glass, or an organic nonlinear optical material is used. The shape may be any shape that resonates in a V-shape in the nonlinear optical material, and may be a shape such as a polyhedron. For V-shaped resonance, the incident surface of the fundamental wave is inclined with respect to the optical axis, and the emission surface of the harmonic and the reflection surface of the fundamental wave each include a surface perpendicular to the optical axis of the fundamental wave. Such a shape may be used. That is, it is only necessary that each tangent plane at each intersection of the optical axis with the emission surface and the reflection surface is perpendicular to the optical axis. As the light source of the fundamental wave, a semiconductor laser, various gases and solid-state lasers can be used, but the use of a semiconductor laser is preferable in terms of miniaturization and easy frequency control. When a semiconductor laser is used as a fundamental wave light source, the oscillation frequency is locked to the resonance frequency of the resonator made of the nonlinear optical material, and a part of the resonance light in the nonlinear optical material is returned to the semiconductor laser in order to stabilize the oscillation frequency. Preferably, a position adjusting means for controlling the phase between the light from the semiconductor laser and the return light is provided. As the position adjusting means, the above-described piezoelectric element, other screws,
Mechanical means combining gears, rails and the like may be used.
本発明装置は、光ディスク、光磁気ディスク等の光記
録媒体の情報読み取り装置（ピックアップ）の検出光源
として用いると、より高記録密度の光記録媒体の情報を
読み取り、誤差も少なく安定的に読み取り可能である。When the device of the present invention is used as a detection light source of an information reading device (pickup) for an optical recording medium such as an optical disk or a magneto-optical disk, it can read information from an optical recording medium having a higher recording density and can read stably with less error. It is.
［作用］ 本発明においては、共振用のミラーがないため装置全
体が小型化され、また光軸調整も容易となるので、光源
の半導体レーザの発振周波数の安定化も容易に行なうこ
とができる。非線形光学材料の基本波の入射面が、基本
波の光軸に対して傾いているため反射光が直接半導体レ
ーザへ戻ることがなく、反射光を遮断するための光アイ
ソレータ等も不要になる。また、基本波が非線形光学材
料内のみで共振し、外部の共振用ミラー等による光学的
な減衰も少ないので、従来と同等以上の高調波の交換効
率が実現できる。[Operation] In the present invention, since there is no mirror for resonance, the entire device is downsized, and the optical axis can be easily adjusted, so that the oscillation frequency of the semiconductor laser as the light source can be easily stabilized. Since the plane of incidence of the fundamental wave of the nonlinear optical material is inclined with respect to the optical axis of the fundamental wave, the reflected light does not return directly to the semiconductor laser, and an optical isolator or the like for blocking the reflected light is not required. In addition, since the fundamental wave resonates only in the nonlinear optical material, and there is little optical attenuation by the external resonance mirror or the like, the harmonic exchange efficiency equal to or higher than the conventional one can be realized.
［実施例］ 第１図に示した本発明の基本的構成の側面図におい
て、一例として半導体レーザ１に単一縦モード，単一横
モード，波長860nm,出力100mWクラスのものを使用し、
非線形光学材料３にKNbO3単結晶を使用した。半導体レ
ーザ１およびKNbO3はペルチェ素子およびその他銅製の
治具等により1/100℃程度の安定度で温度コントロール
した。Embodiment In the side view of the basic configuration of the present invention shown in FIG. 1, a semiconductor laser 1 having a single longitudinal mode, a single transverse mode, a wavelength of 860 nm and an output of 100 mW is used as an example.
KNbO 3 single crystal was used for the nonlinear optical material 3. The temperature of the semiconductor laser 1 and KNbO 3 was controlled at a stability of about 1/100 ° C. by using a Peltier device and other copper jigs.
半導体レーザ光を集光用及びモードマッチング用のレ
ンズ２により最適ビーム形状に整形し、KNbO3自体の共
振器でＶ字共振させ、基本波の共振光を半導体レーザ１
にフィードバックした。その結果、半導体レーザ１の発
振周波数はKNbO3の共振器の共振周波数にロックされ、
またスペクトル線幅も狭窄化し430nmの第２高調波を安
定に発生することができた。The semiconductor laser light is shaped into an optimum beam shape by a converging and mode matching lens 2 and V-shaped resonated by the resonator of the KNbO 3 itself.
Feedback. As a result, the oscillation frequency of the semiconductor laser 1 is locked to the resonance frequency of the KNbO 3 resonator,
Further, the spectral line width was narrowed, and a second harmonic of 430 nm was able to be generated stably.
KNbO3はＶ字共振するときの半導体レーザの光軸と一
致する方の光軸で位相整合が取れるように研磨加工して
使用した。KNbO 3 was used after being polished so that phase matching could be achieved with the optical axis that coincides with the optical axis of the semiconductor laser at the time of V-shaped resonance.
なお、非線形光学材料３の基本波（波長860nm）の入
射面a,第２高調波（波長430nm）の出射面ｂ、基本波の
反射面ｃには以下に示す特性の光学膜が設けられてい
る。An optical film having the following characteristics is provided on the entrance surface a of the nonlinear optical material 3 for the fundamental wave (wavelength 860 nm), the emission surface b of the second harmonic (wavelength 430 nm), and the reflection surface c of the fundamental wave. I have.
a:R＝96.4％（860nm） b:R＝99.9％（860nm）,T＝98.5％（430nm） c:R＝99.9％（860nm） ここで、Ｒは反射率でＴは透過率を示す。a: R = 96.4% (860 nm) b: R = 99.9% (860 nm), T = 98.5% (430 nm) c: R = 99.9% (860 nm) Here, R indicates reflectance and T indicates transmittance.
［発明の効果］ 本発明は、非線形光学材料自体を基本波の共振器とし
て使用し、また基本波の共振光も容易に光源へフィード
バック可能であるため、超小型、光軸調整容易な装置で
周波数安定、狭スペクトル線幅な高調波発生が可能であ
るという優れた効果を有する。また、共振ミラーや光ア
イソレータ等による光学的減衰部も少ないため、高調波
への変換効率も向上する。[Effects of the Invention] The present invention uses a non-linear optical material itself as a resonator of a fundamental wave and can easily feed back the resonance light of the fundamental wave to a light source. It has an excellent effect that harmonics with stable frequency and narrow spectral line width can be generated. In addition, since there are few optically attenuating portions due to a resonance mirror, an optical isolator, and the like, the efficiency of conversion to harmonics is improved.
第１図は本発明装置の基本構成の側面図である。 １…半導体レーザ、３…非線形光学材料 FIG. 1 is a side view of the basic configuration of the device of the present invention. 1: semiconductor laser, 3: nonlinear optical material
Claims (2)
し高調波を発生する非線形光学材料とを備えた高調波発
生装置において、該非線形光学材料の基本波の入射面と
高調波の出射面には基本波が非線形光学材料内で共振す
るよう光学膜が設けられ、該非線形光学材料の形状は基
本波がその中でＶ字形の共振光路をとるように、基本波
の入射面は光軸に対して傾いた平面とされ高調波の出射
面は光軸に対して垂直な面を含む平面又は曲面とされ、
さらに基本波の反射面は光軸に対して垂直な面を含む平
面又は曲面とされていることを特徴とする高調波発生装
置。1. A harmonic generator comprising a light source for generating a fundamental wave, and a nonlinear optical material for converting the wavelength of the fundamental wave to generate a harmonic. An optical film is provided on the exit surface of the element so that the fundamental wave resonates in the nonlinear optical material. The shape of the nonlinear optical material is such that the fundamental wave takes a V-shaped resonance optical path therein, and the incident surface of the fundamental wave. Is a plane inclined with respect to the optical axis, and the emission surface of the harmonic is a plane or a curved surface including a plane perpendicular to the optical axis,
Further, the fundamental wave reflection surface is a flat surface or a curved surface including a surface perpendicular to the optical axis.
求項１記載の高調波発生装置。2. The harmonic generator according to claim 1, wherein the nonlinear optical material has a hemispherical shape.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27523790A JP2900576B2 (en) | 1990-10-16 | 1990-10-16 | Harmonic generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27523790A JP2900576B2 (en) | 1990-10-16 | 1990-10-16 | Harmonic generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04151627A JPH04151627A (en) | 1992-05-25 |
| JP2900576B2 true JP2900576B2 (en) | 1999-06-02 |
Family
ID=17552609
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27523790A Expired - Fee Related JP2900576B2 (en) | 1990-10-16 | 1990-10-16 | Harmonic generator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2900576B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2679050B1 (en) * | 1991-07-09 | 1994-08-26 | Thomson Csf | NON-LINEAR OPTICAL DEVICES. |
-
1990
- 1990-10-16 JP JP27523790A patent/JP2900576B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04151627A (en) | 1992-05-25 |
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