JPS63265479A - Laser device - Google Patents

Laser device

Info

Publication number
JPS63265479A
JPS63265479A JP62183678A JP18367887A JPS63265479A JP S63265479 A JPS63265479 A JP S63265479A JP 62183678 A JP62183678 A JP 62183678A JP 18367887 A JP18367887 A JP 18367887A JP S63265479 A JPS63265479 A JP S63265479A
Authority
JP
Japan
Prior art keywords
mirror
exit
laser beam
exit mirror
laser device
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.)
Granted
Application number
JP62183678A
Other languages
Japanese (ja)
Other versions
JPH0511671B2 (en
Inventor
Kimiharu Yasui
公治 安井
Masaaki Tanaka
正明 田中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP62183678A priority Critical patent/JPS63265479A/en
Priority to KR1019880006600A priority patent/KR910008990B1/en
Priority to US07/201,999 priority patent/US4903271A/en
Priority to EP88108902A priority patent/EP0293907B1/en
Priority to DE8888108902T priority patent/DE3879547T2/en
Publication of JPS63265479A publication Critical patent/JPS63265479A/en
Publication of JPH0511671B2 publication Critical patent/JPH0511671B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08059—Constructional details of the reflector, e.g. shape
    • H01S3/08063—Graded reflectivity, e.g. variable reflectivity mirror
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/02—Constructional details
    • H01S3/03—Constructional details of gas laser discharge tubes
    • H01S3/034—Optical devices within, or forming part of, the tube, e.g. windows, mirrors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0602—Crystal lasers or glass lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08081—Unstable resonators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
    • H01S3/092—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp
    • H01S3/093—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp focusing or directing the excitation energy into the active medium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/06—Construction or shape of active medium
    • H01S3/0602—Crystal lasers or glass lasers
    • H01S3/0615—Shape of end-face
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
    • H01S3/08—Construction or shape of optical resonators or components thereof
    • H01S3/08059—Constructional details of the reflector, e.g. shape
    • H01S3/08068—Holes; Stepped surface; Special cross-section
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/0915—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light
    • H01S3/092—Processes or apparatus for excitation, e.g. pumping using optical pumping by incoherent light of flash lamp

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Lasers (AREA)

Abstract

PURPOSE:To improve light condensing characteristics by a method wherein a partially transmitting part is provided on the exit mirror of a resonator and two parts of a laser beam which are reflected by the partially transmitting part and its circumferential part of the exit mirror respectively are taken outside while their mutual phase difference is cancelled. CONSTITUTION:A laser beam 7a magnified by a magnifying totally reflective mirror 1a is amplified by a laser medium 3. A part of its center part is taken outside through the partially reflective film 20 of an exit mirror 4 and all its circumferential part is taken outside through the non-reflective film 5 of the exit mirror 5. The two parts are synthesized to form an equal phase and solid high quality laser beam 8. A laser beam 7 partially reflected by the partially reflective mirror 20 is again amplified by the laser medium 3 and further reflected and magnified by the magnifying totally reflective mirror 1a. Thus, every time the laser beam 7 goes back and forth in a laser resonator composed of the magnifying totally reflective mirror 1a, and the exit mirror 4, the solid high quality laser beam 8 is emitted outside. With this constitution, a high quality laser beam can be taken out without degrading an oscillation efficiency.

Description

【発明の詳細な説明】[Detailed description of the invention]

［産業上の利用分野］ この発明はレーザ装置に係り、とくに大出力レーザ装置
におけるビーム品質の改良に関するものである。 ［従来の技術］ 第１３図は例えばレーザハンドブック（Ｌａ５ｅｒ１１
ａｎｄｂｏｏｋ　１９７９．　Ｎｏｒｔｈ−ｔｌｏｌｌ
ａｎｄ　ＰｕｂｌｉｓｈｉｎｇＣｏｍｐａｎｙ）に記載
された従来の不安定型共振器を有するレーザ装置の模式
図である。図において、（１）は凹面鏡よりなるコリメ
ートミラー、（２）はこのコリメートミラーに対向配設
された凸面鏡よりなる拡大ミラーであり、両ミラー（１
）　、　（２）は全反射ミラーによって構成されている
。（３）はレーザ媒質でＣ０２レーザ等のガスレーザを
例にとれば放電などにより励起されたガス媒質、ＹＡＧ
レーザなどの固体レーザを例にとればフラッシュランプ
等により励起されたガラス媒質である。 （４）はウィンドミラー、（５）はウィンドミラー（４
）の面上に施された無反射コーテイング膜、（６）は周
囲を覆う箱体、（７）はコリメートミラー（１）と拡大
ミラー（２）とにより構成された共振器内に発生するレ
ーザビーム、（８）は拡大ミラー（２）の周辺部より外
部に取出されたレーザビームである。 次に動作について説明する。コリメートミラー（１）と
拡大ミラー（２）はいわゆる不安定型共振器を構成して
おり、拡大ミラー（２）により反射拡大されたレーザビ
ーム（７）はレーザ媒質（３）により増幅されると共に
、コリメートミラー（１）により平行ビーム（７ａ）に
コリメートされて、拡大ミラー（２）及び拡大ミラー（
２）の周辺部上に反射し、リング状のビームとしてウィ
ンドミラー（４）より外部にとり出される。取出された
リング状のレーザビーム（８）はほとんど等位相で得ら
れるため、レンズ等によって集光することにより中高の
レーザビーム（８）となり、鉄板などの切断、溶接等を
効率よくおこなうことができる。 また、その集光の度合いは、取出されるリング状のレー
ザビーム（８）の内径と外径との比（Ｍ値（Ｍａｇｎｉ
Ｈｅａｔｌｏｎ　ｒａｃｔｅｒ））できまり、Ｍ値が大
きいほど、すなわち、より中づまりで取出されたビーム
はどよく集光される。しかしＭ値を大きくすると発振効
率が著しく悪化するため、工業的に現実にもちいられる
Ｍ値の上限は２程度である。 ［発明が解決しようとする問題点］ 従来のレーザ装置は以上のように構成されているので、
集光特性を向上させるためにＭ値を大きくすると発振効
率が悪化するため、実用的にはＭ値を最高集光性能の得
られる無限大近くまであげられないという問題があった
。また、ウィンドミラー（４）がリング状のレーザビー
ム（８）により不均一に過熱されるため、不均一な内部
応力が発生して通過するレーザビーム（８）の位相分布
をくずし、集光性能を悪化させる等の問題があった。 この発明は上記のような問題点を解消するためになされ
たもので、発振効率の低下を招かずにＭ値が無限大に近
い高品質のレーザビームを取出すことができるレーザ装
置を得ることを目的とする。 ［問題点を解決するための手′段］ この発明に係るレーザ装置は、部分透過部を有する出口
ミラーと、この出口ミラーと対向配置され出口ミラーの
部分透過部で反射されたレーザビームを反射するコリメ
ートミラー又は拡大ミラーとを有する共振器を備えたも
のである。 ［作用コ この発明における出口ミラーは、レーザビームの一部を
透過させることにより、そのビーム形状を従来のリング
状から中づまり状のレーザビームとして取出される、。 ［実施例］ 第１図はこの発明の一実施例に係るレーザ装置の模式図
である。図において、（４）は凸面鏡からなる出口ミラ
ーであり、コリメートミラー（１）に対向する面の中央
部に部分反射率を有する部分反射膜（２０）が設けられ
、拡大ミラーとして働く。また部分反射膜（２０）の周
辺部及び他面側には無反射コーテイング膜（５）が設け
られている。 次に動作について説明する。コリメートミラー（１）及
び出口ミラー（４）の部分反射膜（２０）部はいわゆる
不安定型共振器を構成しており、出口ミラー（４）の部
分反射膜（２０）で反射拡大されたレーザビーム（７）
は、レーザ媒質（３）により増幅されると共にコリメー
トミラー（１）により平行ビームにコリメートされ、出
口ミラー（４）より外部へレーザビーム（８）として取
出される。このレーザビーム（８）は部分反射膜（２０
）を通過する部分と、無反射コーテイング膜（５）を通
過する部分とからなっており、部分反射膜（２０）を通
過する部分は部分透過性をもつので、レーザビーム（８
）は中づまりであり、従来の不安定型共振器で定義され
たＭ値は無限大に相当する。 第２図（ａ）　、　（ｂ）はそれぞれ従来及びこの発明
の一実施例による不安定型共振器で発生したレーザビー
ムをレンズで集光させた場合のパターン形状を模式的に
示す特性図であり、横軸は光軸からの距離、縦軸はビー
ム強度である◎ この実験では両者の発振特性をほぼ同一にするため、部
分反射膜（２０）の反射率は５０％、また部分反射膜（
２０）の径とビーム外径との比は１．５とした（即ち、
Ｍ　−１，５の従来の不安定型共振器の拡大ミラー（２
）に５０％の部分透過性をもたせて、この発明の不安定
型共振器とした）。また、出口ミラー（４）の両面の曲
率は同一としく厚みを一定とし）、レーザビーム（８）
が出口ミラー（４）を通過後も平行ビームであるように
した。第２図（ａ）。 （ｂ）で示される各集光性能を比較すると、この発明に
よるもの（第２図（ｂ））は中央強度が高く、かつ光軸
上に集中したレーザビームが得られることがわかる。ま
た中央の強度の山（メインローブ）には全パワーの約８
２％のレーザパワーが含まれていることが確かめられ、
これは従来の不安定型共振器でのＭ値が無限大での理論
値８０％にほぼ匹敵する値であり、理論限界に近い集光
性が得られていることがわかる。 また、上記の実施例では無反射コーテイング膜（５）を
通過する場合の位相変化と、部分反射膜（２０）を通過
する場合の位相変化との差が小さいため、集光性のよい
位相のよくそろったレーザビーム（８）が得られたが、
部分反射膜（２０）の反射率を上げて部分反射膜（２０
）の膜厚を大きくした場合には、両者の間に生じる位相
差により集光性能が悪化する。 例えば、第３図は集光点での軸上強度の１ｌｅｉ倍にな
る点の直径（集光スポット径）、及びその径内に含まれ
るレーザパワーの全体に対する割合（パワー集中度）と
位相差との関係を示す特性図であり、横軸は位相差（ｄ
ｅｇｒｅｅ）　、縦軸は集光スポット径（−）及びパワ
ー集中度（％）を示す。 曲線（Ａ）は集光スポット径と位相差との関係を示し、
曲線（Ｂ）はパワー集中度と位相差との関係を示す。な
お、Ｍ値は１．５で、部分反射膜（２０）の部分透過性
は５０％とした。また、第３図は波動計算により共振器
内に発生するレーザビーム、及びそれをもちいての集光
点での強度分布を計算した結果にもとづくものである。 一般にスポット径が小さく、パワー集中度が大きい程集
光性能がよいと判断できる。しかし第３図では、例えば
、位相差が０６から４５＠程度内に打消されていれば、
パワー集中度、スポット径とも好ましい結果が得られる
が、１００°以上の位相差が生じた場合には、特にスポ
ット径が著しく悪化し、集光性能が悪化することがわか
る。 この場合は、第４図（ａ）又は（ｂ）に示すようにコリ
メートミラー（１）面中央部の部分反射膜（２０）と同
径の部分に（第４図（ｂ）　）　、あるいは上記中央部
をのぞいて（第４図（ａ））金属薄膜よりなる反射薄膜
（１０）を設け、その厚みが上記位相差を取消すように
構成すればよい。たとえば部分反射膜（２０）を通過す
る場合に、無反射コーテイング膜（５）を通過する場合
より位相が００進むとした場合には、金属薄膜（１０）
の厚みｄは θ ｄ−１λ・□１[Industrial Field of Application] The present invention relates to a laser device, and particularly to improving beam quality in a high-output laser device. [Prior art] Figure 13 shows, for example, the laser handbook (La5er11
andbook 1979. North-troll
FIG. 1 is a schematic diagram of a conventional laser device having an unstable resonator described in the Japanese Patent and Publishing Company. In the figure, (1) is a collimating mirror made of a concave mirror, (2) is a magnifying mirror made of a convex mirror disposed opposite to this collimating mirror, and both mirrors (1
) and (2) are composed of total reflection mirrors. (3) is a laser medium, and if we take a gas laser such as a C02 laser as an example, it is a gas medium excited by discharge etc., and YAG.
For example, a solid-state laser such as a laser is a glass medium excited by a flash lamp or the like. (4) is a wind mirror, (5) is a wind mirror (4
), (6) is a box covering the surrounding area, and (7) is a laser generated in a resonator composed of a collimating mirror (1) and a magnifying mirror (2). Beam (8) is a laser beam taken out from the periphery of the magnifying mirror (2). Next, the operation will be explained. The collimating mirror (1) and the magnifying mirror (2) constitute a so-called unstable resonator, and the laser beam (7) reflected and magnified by the magnifying mirror (2) is amplified by the laser medium (3), It is collimated into a parallel beam (7a) by the collimating mirror (1), and then the magnifying mirror (2) and the magnifying mirror (
2) is reflected onto the periphery of the beam and is taken out from the wind mirror (4) as a ring-shaped beam. The extracted ring-shaped laser beam (8) is obtained with almost the same phase, so by focusing it with a lens etc., it becomes a medium-high laser beam (8), which can be used to efficiently cut and weld iron plates, etc. can. In addition, the degree of convergence is determined by the ratio of the inner diameter and outer diameter (M value (Magni)) of the ring-shaped laser beam (8) to be extracted.
The larger the M value, that is, the more concentrated the beam will be focused. However, if the M value is increased, the oscillation efficiency deteriorates significantly, so the upper limit of the M value that is actually used industrially is about 2. [Problems to be solved by the invention] Since the conventional laser device is configured as described above,
If the M value is increased in order to improve the light collection characteristics, the oscillation efficiency deteriorates, so there is a problem in that it is practically impossible to increase the M value close to infinity where the maximum light collection performance can be obtained. In addition, since the wind mirror (4) is heated non-uniformly by the ring-shaped laser beam (8), non-uniform internal stress is generated and the phase distribution of the passing laser beam (8) is disrupted, resulting in poor focusing performance. There were problems such as worsening of This invention was made to solve the above-mentioned problems, and aims to provide a laser device that can extract a high-quality laser beam with an M value close to infinity without causing a decrease in oscillation efficiency. purpose. [Means for Solving the Problems] A laser device according to the present invention includes an exit mirror having a partially transmitting portion, and a laser beam disposed opposite to the exit mirror to reflect a laser beam reflected by the partially transmitting portion of the exit mirror. It is equipped with a resonator having a collimating mirror or a magnifying mirror. [Operation] The exit mirror in this invention allows a portion of the laser beam to pass therethrough, thereby changing the beam shape from the conventional ring shape to a hollow-shaped laser beam. [Example] FIG. 1 is a schematic diagram of a laser device according to an example of the present invention. In the figure, (4) is an exit mirror made of a convex mirror, and a partial reflection film (20) having partial reflectance is provided at the center of the surface facing the collimating mirror (1), and serves as a magnifying mirror. Further, a non-reflective coating film (5) is provided on the peripheral portion and the other side of the partially reflective film (20). Next, the operation will be explained. The partially reflective film (20) of the collimating mirror (1) and the exit mirror (4) constitute a so-called unstable resonator, and the laser beam reflected and expanded by the partially reflective film (20) of the exit mirror (4) (7)
is amplified by the laser medium (3), collimated into a parallel beam by the collimating mirror (1), and taken out from the exit mirror (4) as a laser beam (8). This laser beam (8) is transmitted through a partially reflective film (20
) and a part that passes through the non-reflective coating film (5).The part that passes through the partially reflective film (20) is partially transparent, so the laser beam (8
) is a blockage, and the M value defined in the conventional unstable resonator corresponds to infinity. FIGS. 2(a) and 2(b) are characteristic diagrams schematically showing pattern shapes when a laser beam generated in an unstable resonator according to a conventional method and an embodiment of the present invention is focused by a lens, respectively. , the horizontal axis is the distance from the optical axis, and the vertical axis is the beam intensity ◎ In this experiment, in order to make the oscillation characteristics of both almost the same, the reflectance of the partially reflective film (20) is 50%, and the partially reflective film (
20) and the beam outer diameter was set to 1.5 (i.e.,
M-1,5 conventional unstable resonator magnifying mirror (2
) was given 50% partial transparency to form the unstable resonator of the present invention). In addition, the curvature of both sides of the exit mirror (4) is the same and the thickness is constant), and the laser beam (8)
The beam remains parallel even after passing through the exit mirror (4). Figure 2(a). Comparing the light focusing performance shown in FIG. 2(b), it can be seen that the one according to the present invention (FIG. 2(b)) has a high center intensity and can obtain a laser beam concentrated on the optical axis. In addition, the central peak of strength (main lobe) has approximately 8 of the total power.
It was confirmed that it contained 2% laser power,
This value is almost comparable to the theoretical value of 80% when the M value is infinite in a conventional unstable resonator, and it can be seen that light focusing performance close to the theoretical limit is obtained. In addition, in the above embodiment, since the difference between the phase change when passing through the non-reflection coating film (5) and the phase change when passing through the partially reflective film (20) is small, the phase change with good focusing property is Although a well-aligned laser beam (8) was obtained,
The partially reflective film (20) is made by increasing the reflectance of the partially reflective film (20).
), the light collection performance deteriorates due to the phase difference generated between the two. For example, Figure 3 shows the diameter of a point that is 1lei times the axial intensity at the focal point (condensed spot diameter), the proportion of the laser power contained within that diameter to the total (power concentration), and the phase difference. , and the horizontal axis is the phase difference (d
egree), the vertical axis indicates the focused spot diameter (-) and the power concentration degree (%). Curve (A) shows the relationship between the focused spot diameter and the phase difference,
Curve (B) shows the relationship between power concentration and phase difference. Note that the M value was 1.5, and the partial transmittance of the partially reflective film (20) was 50%. Furthermore, FIG. 3 is based on the results of calculating the laser beam generated within the resonator and the intensity distribution at the focal point using the wave calculation. Generally, it can be determined that the smaller the spot diameter and the larger the power concentration, the better the light collection performance. However, in Fig. 3, for example, if the phase difference is canceled within about 06 to 45@,
Although favorable results are obtained for both power concentration and spot diameter, it can be seen that when a phase difference of 100° or more occurs, the spot diameter in particular deteriorates significantly and the light collection performance deteriorates. In this case, as shown in Fig. 4(a) or (b), the part with the same diameter as the partial reflection film (20) at the center of the collimating mirror (1) surface (Fig. 4(b)), or the above A reflective thin film (10) made of a thin metal film may be provided except for the central portion (FIG. 4(a)), and the thickness thereof may cancel the above-mentioned phase difference. For example, if the phase advances by 00 when passing through the partially reflective film (20) than when passing through the non-reflective coating film (5), then the metal thin film (10)
The thickness d is θ d−1λ・□1

【ｌ】[l]

と計算される（ここでλはレーザビームの波長である）
。 またこれと同じことは第５図、　＜ａ＞　、　（ｂ）に
示すように、コリメートミラー（１）の中央部に部分反
射膜（２０）と同径の凹（第５図（ｂ））又は凸（第４
図（ｂ））状の段部（１１）を設けても実現でき、また
第６図（ａ）　、　（ｂ）に示すように出口ミラー（４
）の内面側に段部（４０）を設け、拡大ミラー部、即ち
部分反射膜（２０）をコーティングした部分と、拡大ミ
ラー周辺部、即ち無反射コーテイング膜（５）をコーテ
ィングした部分との間に段差を設けても実現できる。こ
の場合の段差の大きさは０］式にもとづいてきめればよ
い。 また、以上の例では不安定型共振器の拡大ミラーとして
凸面鏡の場合を示したが、第７図に示すように出口ミラ
ーに凹面鏡（４１）をもちいて、一度共振器内でビーム
を集光後拡大した構成のものについても、凹面鏡（４１
）の中央部に部分反射率をもつ部分反射膜（２０）を設
けて、部分透過率を有する拡大ミラーとすることにより
同様にして中づまりのモードを発生させることができる
。なお、第４図ないし第７図はいずれも周囲を覆う箱体
を省いてこの発明のレーザ装置の断面構成を示している
。 第８図はこの発明の他の実施例の断面図である。 図において、（ｌａ）は凸面鏡からなる拡大全反射ミラ
ー、（３）はレーザ媒質、（４）は凹面鏡からなる出口
ミラーで、（５）は無反射コーテイング膜、（２０）は
内面の中央部に設けた部分反射膜である。 （６）は箱体、（７）　、　（７ａ）、　（８）はレー
ザビームである。 次に動作について説明する。拡大全反射ミラー（ｌａ）
により拡大されたレーザビーム（７ａ）はレーザ媒質（
３）により増幅され、その中央部の一部が出口ミラー（
４）の部分反射膜（２０）を通して、またその周囲部の
全部が出口ミラー（４）の無反射コーテイング膜（５）
を通して外部に取出され、両者は合成されて等位相かつ
中づまりの高品質レーザビーム（８）となる。一方、部
分反射膜（２０）により部分反射されたレーザビーム（
７）は再びレーザ媒質（３）により増幅され、さらに拡
大全反射ミラー（ｌａ）により反射拡大される。 このようにしてレーザビーム（７）は拡大全反射ミラー
（ｌａ）、出口ミラー（４）よりなるレーザ共振器間を
往復するごとに中づまりの高品質レーザビーム（８）を
外部に出射する。 なお、この実施例では出口ミラー（４）の外面の曲率を
内面の曲率より小さくして、出口ミラー（４）を通過す
るレーザビーム（８）が一般に使用しやすい平行光とな
る例を示しである。 上記実施例では出口ミラー（４）に部分反射膜（２０）
を施して部分反射性をもたせた場合を示したが、第９図
に示すように無コート部分（２１）により部分反射性を
実現してもよい。また、上記実施例では出口ミラー（４
）の内面の部分反射膜（２０）を通過するレーザビーム
（７）と、無反射コーテイング膜（５）を通過するレー
ザビーム（７ａ）間の位相差は一般に小さいので問題に
しなかったが、これを打消す手段をもうければさらに効
果を高めることができる。 この手段としては第８図の部分反射膜（２０）に厚みを
もたせて、無反射コーテイング膜（５）と部分反射膜（
２０）を通過するレーザビーム（７ａ）、　（７）　。 の位相差を打消し、レーザビーム（８）が等位相となる
ようにするか、あるいは第１０図に示すように出口ミラ
ー（４）の外面に段差（２２）を設け、上記２つのレー
ザビーム（７）　、　（７ａ）に対する出口ミラー（４
）内の光路差に差をもたせて位相差を打消してもよい。 さらに第１１図に示すように出口（４）ミラー（４）の
外面と同様の作用をもつ段差（２２）をもつ位相補償ミ
ラー（９）を別にもうけてもよい。 また拡大ミラーについても凸状のもののみ示したが、第
１２図に示すように凹状のミラー（ｌｂ）を用いてもよ
い。 上記の実施例はいずれも出口ミラーとウィンドミラーと
が一体となったものを示したが、従来と同様、ウィンド
ミラー面上に部分透過率を有する凹または凸面鏡よりな
る出口ミラーを設けてもよい。 ［発明の効果］ 以上のように、この発明によれば共振器の出口ミラーに
部分透過部を設けると共に、出口ミラーの部分透過部及
びその周辺部に反射された二つのレーザビームを互いの
位相差を打消して外部に取出す構成としたので、発振効
率を犠牲にすることなく中づまりの集光特性のよいレー
ザビームを得ることができる。したがってこのレーザビ
ームを利用することにより高速で効率よく高精度のレー
ザ加工をおこなうことができる。また、レーザビームは
出口ミラー全体を加熱するため、熱応力が発生しに＜＜
、長期間かつ安定してレーザビームを取出すことができ
る。(where λ is the wavelength of the laser beam)
. In addition, as shown in Fig. 5, <a> and (b), the same thing can be seen in the central part of the collimating mirror (1) with a concave (Fig. 5 (b)) having the same diameter as the partial reflection film (20). or convex (4th
This can also be achieved by providing a stepped portion (11) as shown in Figure 6(b), or an exit mirror (4) as shown in Figures 6(a) and (b).
) is provided with a stepped part (40) on the inner surface side, between the magnifying mirror part, that is, the part coated with the partially reflective film (20), and the peripheral part of the magnifying mirror, that is, the part coated with the non-reflective coating film (5). This can also be achieved by providing a step. In this case, the size of the step may be determined based on the formula. In addition, in the above example, a convex mirror was used as the magnifying mirror of the unstable resonator, but as shown in Fig. 7, a concave mirror (41) is used as the exit mirror, and once the beam is focused inside the resonator, The concave mirror (41
By providing a partial reflection film (20) with partial reflectance at the center of ) to form a magnifying mirror with partial transmittance, the jamming mode can be generated in the same way. It should be noted that each of FIGS. 4 to 7 shows the cross-sectional structure of the laser device of the present invention without the surrounding box. FIG. 8 is a sectional view of another embodiment of the invention. In the figure, (la) is an enlarged total reflection mirror made of a convex mirror, (3) is a laser medium, (4) is an exit mirror made of a concave mirror, (5) is a non-reflection coating film, and (20) is the central part of the inner surface. This is a partially reflective film provided on the (6) is a box, and (7), (7a), and (8) are laser beams. Next, the operation will be explained. Enlarged total reflection mirror (LA)
The laser beam (7a) expanded by the laser medium (
3), and a part of its central part is amplified by the exit mirror (
The non-reflective coating film (5) of the exit mirror (4) passes through the partially reflective film (20) of 4) and its entire surrounding area.
The two laser beams are combined to form a high quality laser beam (8) with equal phase and centering. On the other hand, the laser beam (
7) is again amplified by the laser medium (3), and further reflected and magnified by the magnifying total reflection mirror (la). In this way, each time the laser beam (7) makes a round trip between the laser resonator consisting of the enlarged total reflection mirror (la) and the exit mirror (4), a high-quality laser beam (8) is emitted to the outside. Note that this embodiment shows an example in which the curvature of the outer surface of the exit mirror (4) is made smaller than the curvature of the inner surface, so that the laser beam (8) passing through the exit mirror (4) becomes parallel light that is generally easy to use. be. In the above embodiment, the exit mirror (4) is provided with a partially reflective film (20).
Although a case is shown in which partial reflectivity is provided by applying coating, partial reflectivity may be achieved by using an uncoated portion (21) as shown in FIG. In addition, in the above embodiment, the exit mirror (4
) The phase difference between the laser beam (7) that passes through the partially reflective film (20) on the inner surface of the film and the laser beam (7a) that passes through the non-reflective coating film (5) is generally small, so this was not considered a problem. The effect can be further enhanced by creating a means to counteract it. As a means for this, the partially reflective film (20) shown in FIG.
20) a laser beam (7a) passing through (7). Either cancel out the phase difference between the two laser beams so that the laser beams (8) have the same phase, or provide a step (22) on the outer surface of the exit mirror (4) as shown in FIG. (7), Exit mirror (4) for (7a)
) The phase difference may be canceled by providing a difference in the optical path difference within the range. Furthermore, as shown in FIG. 11, a phase compensation mirror (9) having a step (22) having a similar effect to the outer surface of the exit (4) mirror (4) may be provided. Further, although only a convex magnifying mirror is shown, a concave mirror (lb) may also be used as shown in FIG. Although the above embodiments all show an exit mirror and a wind mirror integrated, it is also possible to provide an exit mirror made of a concave or convex mirror with partial transmittance on the wind mirror surface, as in the past. . [Effects of the Invention] As described above, according to the present invention, the exit mirror of the resonator is provided with a partially transmitting section, and the two laser beams reflected on the partially transmitting section of the exit mirror and its surroundings are aligned relative to each other. Since the phase difference is canceled and the laser beam is extracted to the outside, it is possible to obtain a laser beam with good focusing characteristics without sacrificing oscillation efficiency. Therefore, by using this laser beam, it is possible to perform high-speed, efficient, and highly accurate laser processing. In addition, since the laser beam heats the entire exit mirror, thermal stress is generated.
, the laser beam can be extracted stably for a long period of time.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の一実施例の模式図、第２図（ａ）　
、　（ｂ）は各々従来及びこの発明の一実施例によるレ
ーザ装置の集光特性を示す特性図、第３図は集光点での
集光スポット径及びパワー集中度と位相差との関係を示
す特性図、第４図（ａ）　、　（ｂ）、第５図（ａ）　
、　（ｂ）　、第６図（ａ）　、　（ｂ）　、第７図〜
第１２図はそれぞれこの発明の他の実施例の模式図、第
１３図は従来のレーザ装置の一例を示す模式図である。 （１）・・・プリメートミラー、（ｌａ）・・・拡大ミ
ラー、（３）・・・レーザ媒質、（４）・・・凸面鏡、
（５）・・・無反射コーテイング膜、（７）　、　　（
７ａ）、　（８）・・・レーザビーム、（９）・・・位
相補償ミラー、（１０）・・・反射薄膜、（１１）、　
（２２）、　（４０）・・・段部、（２０）・・・部分
反射膜、（４１）・・・凹面鏡。 なお、図中、同一符号は同−又は相当部分を示す。 代理人　弁理士　佐　々　木　宗　治 ？１′￥１図 １ニコリメートミラー ２０Ｉｐ＃、？ｌ”Ｅ呆 ８＋！２　　図 九ｆｄ＋　／１’”５　ｎ距籠 第３図 ０　　　　　　　　　　？□　　　　　　　　　ｒｌ。 イ立、４目１６−（べｊ）ｌ’ｅす 第　４　図 （Ｇ） （ｂ） ＩＯ二反酊薄臘 ｕｓ　　５　　面 １１：段仰 の６　図 （ｂ） ４０：凶却Figure 1 is a schematic diagram of an embodiment of this invention, Figure 2 (a)
, (b) are characteristic diagrams showing the focusing characteristics of a conventional laser device and an embodiment of the present invention, respectively, and FIG. 3 shows the relationship between the focused spot diameter and power concentration at the focusing point and the phase difference. Characteristic diagrams shown in Fig. 4 (a), (b), Fig. 5 (a)
, (b), Figure 6 (a), (b), Figure 7~
FIG. 12 is a schematic diagram of another embodiment of the present invention, and FIG. 13 is a schematic diagram showing an example of a conventional laser device. (1) Primate mirror, (la) Magnifying mirror, (3) Laser medium, (4) Convex mirror,
(5)...Non-reflective coating film, (7), (
7a), (8)... Laser beam, (9)... Phase compensation mirror, (10)... Reflective thin film, (11),
(22), (40)...Stepped portion, (20)...Partial reflection film, (41)...Concave mirror. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent: Patent attorney Souji Sasaki? 1′￥1Figure 1 Nikolimate mirror 20Ip#, ? l"E 8+! 2 Figure 9fd+ /1'"5 nLength 3 Figure 0? □ rl. I stand, 4 eyes 16-(bej)l'e 4th figure (G) (b) IO Nitan drunkenness us 5 Face 11: 6th stage elevation figure (b) 40: Atrocities

Claims (15)

【特許請求の範囲】[Claims] （１）部分透過部を有する出口ミラーと、この出口ミラ
ーと対向配置され上記出口ミラーの部分透過部で反射さ
れたレーザビームを反射するコリメートミラー又は拡大
ミラーとを備えた共振器を具備してなるレーザ装置。(1) A resonator comprising an exit mirror having a partially transmitting portion, and a collimating mirror or a magnifying mirror disposed opposite to the exit mirror and reflecting the laser beam reflected by the partially transmitting portion of the exit mirror. A laser device. （２）部分透過部を有する出口ミラーと、この出口ミラ
ーと対向配置され上記出口ミラーの部分透過部で反射さ
れ拡大されたレーザビームを上記出口ミラー及びその周
辺部に反射させるコリメートミラーとを備えた共振器を
具備してなる特許請求の範囲第１項記載のレーザ装置。(2) An exit mirror having a partially transmitting part, and a collimating mirror disposed opposite to the exit mirror and reflecting the enlarged laser beam reflected by the partially transmitting part of the exit mirror onto the exit mirror and its surrounding area. 2. A laser device according to claim 1, comprising a resonator. （３）部分透過部を有する出口ミラーと、この出口ミラ
ーと対向配置され出口ミラーの部分透過部で反射された
レーザビームを拡大して上記出口ミラー部分透過部及び
その周辺部に反射させる拡大ミラーとを備えた共振器を
具備してなる特許請求の範囲第１項記載のレーザ装置。(3) an exit mirror having a partially transmitting section, and a magnifying mirror disposed opposite to the exit mirror for enlarging the laser beam reflected by the partially transmitting section of the exit mirror and reflecting it onto the partially transmitting section of the exit mirror and its surrounding area; A laser device according to claim 1, comprising a resonator comprising: （４）上記出口ミラーは凹または凸面鏡の中央部に部分
反射率を有する反射膜を設けて形成されている特許請求
の範囲第１項〜第３項の何れかに記載のレーザ装置。(4) The laser device according to any one of claims 1 to 3, wherein the exit mirror is formed by providing a reflective film having partial reflectance in the center of a concave or convex mirror. （５）上記凹又は凸面鏡の両面の曲率が同一である特許
請求の範囲第４項記載のレーザ装置。(5) The laser device according to claim 4, wherein the concave or convex mirror has the same curvature on both sides. （６）上記出口ミラーに対向するコリメートミラー面の
中央部に、上記出口ミラーの部分透過部と同径の反射薄
膜を設けた特許請求の範囲第１項、第２項、第４項及び
第５項のいずれかに記載のレーザ装置。(6) Claims 1, 2, 4 and 4, wherein a reflective thin film having the same diameter as the partially transmitting part of the exit mirror is provided in the center of the collimating mirror surface facing the exit mirror. The laser device according to any one of Item 5. （７）出口ミラーに対向するコリメートミラー面中央部
に上記出口ミラーの部分透過部と同径の段部を設けた特
許請求の範囲第１項、第２項、第４項及び第５項のいず
れかに記載のレーザ装置。(7) Claims 1, 2, 4, and 5, wherein a step portion having the same diameter as the partially transparent portion of the exit mirror is provided at the center of the collimating mirror surface facing the exit mirror. The laser device according to any one of the above. （８）出口ミラーの部分透過部とその周辺部には段差が
ある特許請求の範囲第１項、第２項、第４項及び第５項
のいずれかに記載のレーザ装置。(8) The laser device according to any one of claims 1, 2, 4, and 5, wherein there is a step between the partially transmitting part of the exit mirror and its peripheral part. （９）上記出口ミラーと対向するコリメートミラー面中
央部の出口ミラーの部分透過部と同径の部分を除いて反
射薄膜を設けた特許請求の範囲第１項、第２項、第４項
及び第５項のいずれかに記載のレーザ装置。(9) Claims 1, 2, and 4, in which a reflective thin film is provided except for a portion having the same diameter as the partially transmitting portion of the exit mirror at the center of the collimating mirror surface facing the exit mirror; The laser device according to any one of Item 5. （１０）上記反射薄膜の厚みｄは ｄ＝λ・θ／３６０ 但し、λ：レーザビームの波長 θ：拡大ミラー及びミラー周辺部を通る 各レーザビームの位相差 である特許請求の範囲第９項記載のレーザ装置。(10) The thickness d of the reflective thin film is d=λ・θ/360 However, λ: wavelength of laser beam θ: Passes through the magnifying mirror and the surrounding area of the mirror Phase difference of each laser beam A laser device according to claim 9. （１１）上記出口ミラーの内外面の曲率が異なる特許の
範囲第３項記載のレーザ装置。(11) The laser device according to item 3 of the patent, wherein the exit mirror has different curvatures on its inner and outer surfaces. （１２）上記拡大ミラーが凹又は凸面鏡である特許請求
の範囲第３項又は第１１項記載のレーザ装置。(12) The laser device according to claim 3 or 11, wherein the magnifying mirror is a concave or convex mirror. （１３）上記出口ミラーの部分透過部とその周辺部を通
過するレーザビームの位相差を打消す手段を設けてなる
特許請求の範囲第３項又は第１１項、第１２項の何れか
に記載のレーザ装置。(13) Claim 3, Claim 11, or Claim 12, further comprising means for canceling the phase difference between the laser beam passing through the partially transmitting part of the exit mirror and its peripheral part. laser equipment. （１４）上記出口ミラーの外面に段差を設けてなる特許
請求の範囲第１３項記載のレーザ装置。(14) The laser device according to claim 13, wherein a step is provided on the outer surface of the exit mirror. （１５）上記共振器から取出されたレーザビームの通路
に段差を有する位相補償ミラーを設けてなる特許請求の
範囲第１３項記載のレーザ装置。(15) A laser device according to claim 13, further comprising a phase compensation mirror having a step in the path of the laser beam taken out from the resonator.
JP62183678A 1986-12-08 1987-07-24 Laser device Granted JPS63265479A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
JP62183678A JPS63265479A (en) 1986-12-08 1987-07-24 Laser device
KR1019880006600A KR910008990B1 (en) 1987-06-03 1988-06-02 Laser apparatus
US07/201,999 US4903271A (en) 1987-06-03 1988-06-03 Laser apparatus
EP88108902A EP0293907B1 (en) 1987-06-03 1988-06-03 Laser apparatus
DE8888108902T DE3879547T2 (en) 1987-06-03 1988-06-03 LASER APPARATUS.

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP61-291786 1986-12-08
JP29178686 1986-12-08
JP62183678A JPS63265479A (en) 1986-12-08 1987-07-24 Laser device

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP4228931A Division JPH07105545B2 (en) 1986-12-08 1992-08-27 Laser equipment

Publications (2)

Publication Number Publication Date
JPS63265479A true JPS63265479A (en) 1988-11-01
JPH0511671B2 JPH0511671B2 (en) 1993-02-16

Family

ID=26502017

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62183678A Granted JPS63265479A (en) 1986-12-08 1987-07-24 Laser device

Country Status (1)

Country Link
JP (1) JPS63265479A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009145107A1 (en) * 2008-05-29 2009-12-03 浜松ホトニクス株式会社 Laser light source
KR20190129441A (en) * 2018-05-11 2019-11-20 엘지이노텍 주식회사 A surface-emitting laser packgae and optical module including the same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61199686A (en) * 1985-03-01 1986-09-04 Mitsubishi Electric Corp Unstable laser resonator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61199686A (en) * 1985-03-01 1986-09-04 Mitsubishi Electric Corp Unstable laser resonator

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2009145107A1 (en) * 2008-05-29 2009-12-03 浜松ホトニクス株式会社 Laser light source
JP2009289991A (en) * 2008-05-29 2009-12-10 Hamamatsu Photonics Kk Laser light source
US8295321B2 (en) 2008-05-29 2012-10-23 Hamamatsu Photonics K.K. Laser light source
KR20190129441A (en) * 2018-05-11 2019-11-20 엘지이노텍 주식회사 A surface-emitting laser packgae and optical module including the same

Also Published As

Publication number Publication date
JPH0511671B2 (en) 1993-02-16

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