JPS6151776B2 - - Google Patents
Info
- Publication number
- JPS6151776B2 JPS6151776B2 JP2714781A JP2714781A JPS6151776B2 JP S6151776 B2 JPS6151776 B2 JP S6151776B2 JP 2714781 A JP2714781 A JP 2714781A JP 2714781 A JP2714781 A JP 2714781A JP S6151776 B2 JPS6151776 B2 JP S6151776B2
- Authority
- JP
- Japan
- Prior art keywords
- crystal
- rotation
- wavelength
- laser beam
- laser
- 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
Links
- 239000013078 crystal Substances 0.000 claims description 60
- 230000010355 oscillation Effects 0.000 claims description 16
- 230000003287 optical effect Effects 0.000 claims description 9
- 238000000034 method Methods 0.000 description 8
- 229910013641 LiNbO 3 Inorganic materials 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 5
- 238000010521 absorption reaction 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
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Description
【発明の詳細な説明】
本発明は、レーザレーダ装置あるいは分子吸光
分析用レーザ装置等に関し、特に非線形光学結晶
を用いて和周波、差周波、パラメトリツク発振を
行なわせる多波長レーザ発振装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser radar device or a laser device for molecular absorption analysis, and more particularly to a multiwavelength laser oscillation device that uses a nonlinear optical crystal to perform sum frequency, difference frequency, and parametric oscillation.
従来、この種の装置は、第１図Ａに示すように
非線形光学結晶２を、その対称点４を回転中心５
として、回転テーブル３に載置して回転させ、波
長変換させていた。ところが、この場合には、結
晶の入射面寸法に制限があり、又、入射レーザビ
ームにも有効径があるため、結晶の回転角許容範
囲は制限され、発振波長範囲も制限されるという
欠点があつた。たとえば第１図Ｂのように、発振
波長を変えるために結晶２を回転させた場合、入
射レーザビーム１の周辺部のビーム７について
は、結晶２の入射面からはずれ、該結晶２の側面
より入射する。そのため、結晶中での該ビーム７
の進行方向は、入射レーザビーム１の径をＡφと
し、ビーム７の径をｄφとすると、主成分６（Ａ
−ｄ）φとは大幅に異なるようになる。このビー
ムは、変換光を発生させる為の条件を到底満足し
得ないため、損失となる。すなわち、Ａφ中ｄφ
の光は波長変換されないことを意味する。さら
に、入射レーザビームの強度分布を考慮すれば、
もつと複雑となり単純に変換効率の損失を指定す
ることはできない。 Conventionally, this type of device has a nonlinear optical crystal 2 with a point of symmetry 4 as a center of rotation 5, as shown in FIG. 1A.
The wavelength was converted by placing it on a rotary table 3 and rotating it. However, in this case, the dimensions of the incident surface of the crystal are limited, and the incident laser beam also has an effective diameter, so the permissible rotation angle range of the crystal is limited, and the oscillation wavelength range is also limited. It was hot. For example, when the crystal 2 is rotated to change the oscillation wavelength as shown in FIG. incident. Therefore, the beam 7 in the crystal
When the diameter of the incident laser beam 1 is Aφ and the diameter of the beam 7 is dφ, the traveling direction of
-d) become significantly different from φ. This beam is a loss because it cannot satisfy the conditions for generating converted light. That is, dφ in Aφ
This means that the light is not wavelength converted. Furthermore, if we consider the intensity distribution of the incident laser beam,
However, it becomes complicated and it is not possible to simply specify the conversion efficiency loss.
そのために、入射レーザビームを集光して入射
させる方法や、入射レーザビームを平行移動して
入射させる方法が考えられるが、前者は、結晶の
損傷閾値の問題があり、後者は、光学系が複雑に
なるため、コストアツプと共に、発振波長と入射
レーザ波長の制御が複雑となる問題がある。ま
た、結晶寸法を大きくする方法もあるが、その場
合には、コストが大幅に上昇するという問題があ
る。 To this end, methods can be considered, such as focusing the incident laser beam and moving the incident laser beam in parallel, but the former has problems with the damage threshold of the crystal, and the latter has problems with the optical system. Due to the complexity, there are problems in that not only the cost increases but also the control of the oscillation wavelength and the incident laser wavelength becomes complicated. There is also a method of increasing the crystal size, but in that case there is a problem that the cost increases significantly.
本発明は、斯かる欠点に鑑みてなされたもの
で、結晶の回転中心を、結晶の屈折率に応じて結
晶の対称点よりずらすことによつて、回転角許容
範囲を増加させ、変換発振波長を増加させること
を可能とした多波長レーザ発振装置を提供するこ
とを目的とする。 The present invention has been made in view of such drawbacks, and by shifting the center of rotation of the crystal from the symmetry point of the crystal according to the refractive index of the crystal, the permissible range of rotation angle is increased, and the conversion oscillation wavelength is increased. An object of the present invention is to provide a multi-wavelength laser oscillation device that makes it possible to increase the wavelength.
即ち、本発明は、非線形結晶の回転中心を、結
晶中の屈折率及び結晶の入出射面からビームがは
ずれないことを考慮して決定すれば、相当広範囲
に渡り、波長変換を行なうことが可能となること
に基づくものであつて、少なくとも１本の波長可
変な入射レーザ光と、非線形光学結晶と、結晶を
回転するのに必要とする回転テーブルとより構成
され、さらに、回転テーブル上に固定された非線
形結晶の回転中心を、結晶の最大回転時にレーザ
ビームが結晶の対称点を通るように設定して成
り、変換波長範囲を増加させることを可能にした
ものである。 That is, in the present invention, if the center of rotation of the nonlinear crystal is determined by taking into consideration the refractive index in the crystal and the fact that the beam does not deviate from the entrance/exit plane of the crystal, it is possible to perform wavelength conversion over a fairly wide range. It consists of at least one wavelength-tunable incident laser beam, a nonlinear optical crystal, and a rotating table necessary to rotate the crystal, and is further fixed on the rotating table. The center of rotation of the nonlinear crystal is set so that the laser beam passes through the symmetry point of the crystal at the time of maximum rotation of the crystal, making it possible to increase the conversion wavelength range.
以下、本発明を図面に示す実施例に基づいて説
明する。 Hereinafter, the present invention will be explained based on embodiments shown in the drawings.
第２図Ａ，Ｂは本発明多波長レーザ発振装置に
おける結晶回転方式を示す平面図、第３図Ａ，Ｂ
は本発明多波長レーザ発振装置においてLiNbO3
結晶を使用した回転方式の一例を示す平面図であ
る。 Figures 2A and B are plan views showing the crystal rotation method in the multi-wavelength laser oscillation device of the present invention, Figures 3A and B
is LiNbO 3 in the multi-wavelength laser oscillation device of the present invention.
FIG. 2 is a plan view showing an example of a rotation method using a crystal.
本発明多波長レーザ発振装置は、少なくとも１
台の波長（周波数）可変な入射レーザ装置と、非
線形光学結晶と、該結晶を回転するのに必要とす
る回転テーブルとを備えて構成される。 The multi-wavelength laser oscillation device of the present invention comprises at least one
It is constructed with a wavelength (frequency) variable incident laser device, a nonlinear optical crystal, and a rotary table required to rotate the crystal.
第３図Ａ，Ｂに示す実施例においては、非線形
光学結晶２として、LiNbO3結晶を用いており、
該結晶２を回転テーブル３上に載置固定してあ
る。このLiNbO3結晶を用いて、0.58μｍ〜0.84
μｍにて発振するDyeレーザ光（ビーム径10mm
φ）と、1.06μｍにて発振するYAGレーザ光
（ビーム径10mmφ）との差周波発生（1.3μｍ〜
4.0μｍ）を行なわせる場合、結晶２の回転角
は、結晶のＣ軸に対して60゜カツトの結晶であれ
ば、約−30゜から＋30゜になる（75℃の結晶温度
に対して）。第４図は、差周波発振波長と結晶の
回転角との関係を示したグラフであり、横軸は、
差周波発振波長、縦軸は結晶の０゜からの回転角
を表わしている。差周波（和周波）発生は、２種
類のレーザビームを同軸上に重ね合わせて、結晶
に入射させることにより得られる。 In the embodiment shown in FIGS. 3A and 3B, a LiNbO 3 crystal is used as the nonlinear optical crystal 2,
The crystal 2 is placed and fixed on a rotary table 3. Using this LiNbO 3 crystal, 0.58 μm to 0.84 μm
Dye laser beam oscillated at μm (beam diameter 10mm)
φ) and a YAG laser beam (beam diameter 10mmφ) that oscillates at 1.06μm (1.3μm~
4.0 μm), the rotation angle of crystal 2 will be approximately -30° to +30° (for a crystal temperature of 75°C) if the crystal is cut 60° from the C axis of the crystal. . FIG. 4 is a graph showing the relationship between the difference frequency oscillation wavelength and the rotation angle of the crystal, and the horizontal axis is
The difference frequency oscillation wavelength, the vertical axis represents the rotation angle from 0° of the crystal. Difference frequency (sum frequency) generation is obtained by superimposing two types of laser beams on the same axis and making them incident on a crystal.
入射面寸法20mm×20mm、結晶の長さ25mmの
LiNbO3結晶について、回転中心は次のように決
定される。 Incident surface dimensions: 20mm x 20mm, crystal length: 25mm
For LiNbO 3 crystal, the center of rotation is determined as follows.
−30゜の回転角を必要とする場合は、第４図よ
り、Dyeレーザ光0.82μｍと1.064μｍとで差周波
発生を行なわせる時である。その場合、差周波光
は3.58μｍであり、屈折率は約2.1であるから、
30゜の入射角に対して、13.8゜の屈折角が生じ
る。この屈折角で結晶中を進行するレーザビーム
１の中心線１ａが、結晶２の対称点４を通るよう
にして、結晶中のレーザビームの進む道筋を決
め、入射面と交わる点でレーザの入射方向を決定
し（30゜）、その入射ビームの中心線１ａの延長
線１ｂが、結晶の回転角０゜の時の結晶中を進む
レーザビームの中心線１ｃと交わる点を、回転中
心５とすれば、レーザビーム１は入射面、出射面
ではずれることはなくなる。そのような方法で決
定した結晶の回転中心５は、この実施例では、結
晶の対称点４より約7.5mm入射面側に移動した点
に相当する。第３図Ａは以上のような方法で決定
された結晶の回転中心の位置を示している。同図
Ｂは、その回転中心で＋30゜回転したビームの入
射と結晶の進行の様子を示したもので、この場合
にも入出射面でビームがはずれていないことがわ
かる。ただし＋30゜の回転は1.3μｍの差周波発
生の場合であり、屈折率は約2.2である。 When a rotation angle of -30 degrees is required, as shown in FIG. 4, it is time to generate a difference frequency using Dye laser beams of 0.82 .mu.m and 1.064 .mu.m. In that case, the difference frequency light is 3.58 μm and the refractive index is about 2.1, so
For an angle of incidence of 30°, a refraction angle of 13.8° results. The center line 1a of the laser beam 1 traveling through the crystal at this refraction angle passes through the symmetry point 4 of the crystal 2, and the path of the laser beam in the crystal is determined, and the laser beam enters at the point where it intersects with the plane of incidence. The direction is determined (30°), and the point where the extension line 1b of the center line 1a of the incident beam intersects with the center line 1c of the laser beam traveling through the crystal when the rotation angle of the crystal is 0° is determined as the center of rotation 5. Then, the laser beam 1 will not be deviated from the entrance surface and the exit surface. In this example, the center of rotation 5 of the crystal determined by such a method corresponds to a point moved approximately 7.5 mm toward the incident plane from the point of symmetry 4 of the crystal. FIG. 3A shows the position of the center of rotation of the crystal determined by the method described above. Figure B shows the incidence of a beam rotated by +30° around the center of rotation and the progress of the crystal, and it can be seen that the beam does not deviate from the entrance/exit plane in this case as well. However, the +30° rotation is for generation of a difference frequency of 1.3 μm, and the refractive index is approximately 2.2.
本発明は、以上説明したように、結晶の屈折率
を考慮することによつて、結晶の回転中心を決定
し、それによつて広範囲の角度で結晶を回転する
ことができ、変換波長範囲を増加させることがで
きる。 As explained above, the present invention determines the center of rotation of the crystal by considering the refractive index of the crystal, thereby making it possible to rotate the crystal at a wide range of angles and increasing the conversion wavelength range. can be done.
第１図Ａ，Ｂは従来の多波長レーザ発振装置に
おける結晶回転方式を示す平面図、第２図Ａ，Ｂ
は本発明多波長レーザ発振装置における結晶回転
方式を示す平面図、第３図Ａ，Ｂは本発明多波長
レーザ発振装置においてLiNbO3結晶を使用した
回転方式の一例を示す平面図、第４図は差周波発
振波長と結晶の回転角との関係を示したグラフで
ある。
１……入射レーザビーム、２……非線形光学結
晶、３……回転テーブル、４……結晶の対称点、
５……結晶の回転中心、６……入射レーザビーム
の主成分、７……入射レーザビームの周辺部のビ
ーム。
Figures 1A and B are plan views showing the crystal rotation method in a conventional multi-wavelength laser oscillation device, Figures 2A and B
3A and 3B are plan views showing an example of the rotation method using LiNbO 3 crystal in the multi-wavelength laser oscillation device of the present invention, and FIG. is a graph showing the relationship between the difference frequency oscillation wavelength and the rotation angle of the crystal. 1...Incoming laser beam, 2...Nonlinear optical crystal, 3...Rotary table, 4...Symmetry point of crystal,
5...Center of rotation of the crystal, 6...Main component of the incident laser beam, 7...Beam at the periphery of the incident laser beam.
Claims (1)
レーザ装置と、非線形光学結晶と、結晶を回転す
るのに必要な回転テーブルとを備え、且つ、上記
非線形光学結晶の回転中心を、該結晶の最大回転
時にレーザビームが該結晶の対称点を通るよう決
定して、該結晶を上記回転テーブル上に固定した
ことを特徴とする多波長レーザ発振装置。1.Equipped with at least one wavelength (frequency) variable incident laser device, a nonlinear optical crystal, and a rotation table necessary for rotating the crystal, and set the rotation center of the nonlinear optical crystal to the maximum of the crystal. A multi-wavelength laser oscillation device characterized in that the crystal is fixed on the rotary table, with the laser beam being determined to pass through a point of symmetry of the crystal during rotation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2714781A JPS57141618A (en) | 1981-02-26 | 1981-02-26 | Multiwavelength laser oscillator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2714781A JPS57141618A (en) | 1981-02-26 | 1981-02-26 | Multiwavelength laser oscillator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57141618A JPS57141618A (en) | 1982-09-02 |
| JPS6151776B2 true JPS6151776B2 (en) | 1986-11-10 |
Family
ID=12212930
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2714781A Granted JPS57141618A (en) | 1981-02-26 | 1981-02-26 | Multiwavelength laser oscillator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57141618A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63159832A (en) * | 1986-12-24 | 1988-07-02 | Hamamatsu Photonics Kk | Wavelength variable laser device |
| JPS63159831A (en) * | 1986-12-24 | 1988-07-02 | Hamamatsu Photonics Kk | Optical parametric oscillator |
| JPS63159829A (en) * | 1986-12-24 | 1988-07-02 | Hamamatsu Photonics Kk | Wavelength variable laser device |
| JPS63165825A (en) * | 1986-12-27 | 1988-07-09 | Hamamatsu Photonics Kk | Variable wavelength laser device |
| JPS63165826A (en) * | 1986-12-27 | 1988-07-09 | Hamamatsu Photonics Kk | Variable wavelength laser device |
| JPS63170982A (en) * | 1987-01-08 | 1988-07-14 | Hamamatsu Photonics Kk | Wavelength variable laser device |
| JP2687127B2 (en) * | 1987-12-29 | 1997-12-08 | 浜松ホトニクス株式会社 | Optical parametric oscillator |
-
1981
- 1981-02-26 JP JP2714781A patent/JPS57141618A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57141618A (en) | 1982-09-02 |
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