JPH057046A - Q-switched control laser system - Google Patents

Abstract

PURPOSE:To fabricate a two-dimensional diffraction grating which is superior in diffraction efficiency by forming an ultrasonic wave medium of an ultrasonic Q-switch into a quadrilateral with one pair of opposite sides parallel and other sides tilted at respective predetermined angles relative to the pair of parallel sides. CONSTITUTION:An ultrasonic medium 40 of a Q-switch 60 is formed from a fused quartz or the like, and the medium is, at one end thereof, shaped into an oblique surface 43. The angle of this oblique surface 43 with respect to an upper surface 41 and a lower surface 42 of the ultrasonic medium 40, both being parallel to each other, is 45 degrees. A transducer 50, which is made of a lithium niobate lamina or equivalents, is adhesively disposed at a part of the end of the upper surface 41 which is defined by the normal extending from the lower end of the oblique surface 43. Ultrasonic waves applied into the ultrasonic medium 40 from this transducer 50 are reflected from the surface 43 at right angles after having traveled in the y-direction, and the they are absorbed by means of an ultrasonic wave absorber 40a affixed to an another oblique surface 44 after having propagated in the x-direction. Thus, there is produced, inside the ultrasonic medium 40 in proximity to the oblique surface 43, an orthogonal region for ultrasonic waves where ultrasonic waves propagate in two directions, whereby inconsistencies in the density of this area constitute a two-dimensional diffraction grating.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は超音波Ｑスィッチ制御に
よりパルスレーザ光を発生させるＱスィッチ制御レーザ
装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Q switch control laser device for generating pulsed laser light by ultrasonic Q switch control.

【０００２】[0002]

【従来の技術】周知のように、レーザ装置は強力で強い
指向性をもつコヒーレントな光を発生するもので、その
応用分野は材料加工や計測の分野に止まらず、最近では
医学や化学工業の分野にも広く浸透している。かかる応
用に当たって強力なレーザ光を発生させる上で非常に重
要な役割を果たす技術の一つにＱスィッチがあり、よく
知られているようにこのＱスィッチはレーザ共振系内に
組み込まれレーザ発振を抑止する機能を有する光学素子
である。2. Description of the Related Art As is well known, laser devices generate coherent light with a strong and strong directivity, and their application fields are not limited to the fields of material processing and measurement. Widely used in the field. One of the technologies that plays a very important role in generating a strong laser beam in such an application is a Q switch, and as is well known, this Q switch is incorporated in a laser resonance system to cause laser oscillation. It is an optical element having a function of suppressing.

【０００３】すなわち、Ｑスィッチがオンつまり抑止の
状態ではレーザ媒質が励起されても発振は起きず、媒質
内に大きな反転分布が形成される。この状態でＱスィッ
チをオフにすると急激にレーザが発振して、それまでレ
ーザ媒質内に蓄積されていたエネルギが一気に放出され
るためジャイアントパルスと呼ばれる瞬間的に極めて高
強度のレーザパルスが出力され、一般にそのパルス幅は
10〜100ns とごく短くピークパワーは連続発振時の1000
〜10000 倍になる。That is, when the Q switch is on, that is, when the laser medium is suppressed, oscillation does not occur even if the laser medium is excited, and a large population inversion is formed in the medium. When the Q switch is turned off in this state, the laser abruptly oscillates and the energy accumulated in the laser medium until then is released all at once, so that a very high intensity laser pulse called a giant pulse is momentarily output. , The pulse width is
Very short 10 to 100 ns and peak power is 1000 during continuous oscillation.
~ 10,000 times.

【０００４】このＱスィッチにはレーザ共振系の１対の
ミラー中の一方を回転させる機械的なＱスィッチ，電気
光学効果を利用するＥＯ方式のＱスィッチ，音響光学効
果を利用するＡＯ方式のＱスィッチ等が知られており、
本発明はこの内のＡＯ方式のＱスィッチにより制御され
るレーザ装置に関する。このＡＯ方式のＱスィッチはパ
ルス発振の高頻度繰り返しが可能で、安価で、立ち上が
り波形が比較的急峻なパルスが得られる特長を有し、本
発明ではこれを便宜上超音波Ｑスィッチと呼ぶこととす
る。以下、図８以降を参照しながらこの超音波Ｑスィッ
チを組み込んだレーザ装置の若干の従来例を説明する。The Q switch is a mechanical Q switch that rotates one of a pair of mirrors of a laser resonance system, an EO type Q switch that uses the electro-optical effect, and an AO type Q switch that uses the acousto-optical effect. Known as switches,
The present invention relates to a laser device controlled by an AO type Q switch. This AO type Q switch has a feature that high frequency repetition of pulse oscillation is possible, it is inexpensive, and a pulse having a relatively sharp rising waveform is obtained. In the present invention, this is called an ultrasonic Q switch for convenience. To do. Hereinafter, some conventional examples of a laser device incorporating the ultrasonic Q switch will be described with reference to FIG. 8 and subsequent figures.

【０００５】図８において、レーザ媒質10は例えばNdを
含むＹＡＧのロッドで、これを挟むように全反射ミラー
31と部分反射性の出力ミラー32を設けて通例のようにレ
ーザ共振系を構成し、レーザ媒質10を励起光ELで光励起
することによりこの共振系をレーザ発振させる。超音波
Ｑスィッチ60はレーザ共振系のレーザ光Ｌの光路内に挿
入され、溶融石英等のブロックである超音波媒体40の端
面43に電気エネルギを超音波に変換するトランスデュー
サ50として例えばリチウムナイオベートの薄片を接着し
てなる。トランスデューサ50は高周波電源70から図では
トランスにより簡略に示されたインピーダンス整合回路
71を介して駆動され、それによって発生される超音波は
超音波媒体10内をレーザ光Ｌの光路とほぼ直角な図では
ｘで示す方向に進行し、超音波媒体40の下面42ともう一
方の斜めな端面44との間の楔状の部分に入り、端面44上
に設けられた薄い鉛板等の超音波吸収材40ａによって吸
収ないしはトラップされる。In FIG. 8, a laser medium 10 is, for example, a YAG rod containing Nd, and a total reflection mirror is provided so as to sandwich the rod.
31 and a partially reflective output mirror 32 are provided to form a laser resonance system as usual, and the resonance system is oscillated by optically exciting the laser medium 10 with the excitation light EL. The ultrasonic Q switch 60 is inserted into the optical path of the laser light L of the laser resonance system, and is applied to the end face 43 of the ultrasonic medium 40, which is a block such as fused quartz, as a transducer 50 for converting electric energy into ultrasonic waves, such as lithium niobate. It is made by adhering thin flakes. The transducer 50 is an impedance matching circuit, which is simply shown by a transformer in the figure from the high frequency power source 70.
The ultrasonic waves driven by 71 travel in the ultrasonic medium 10 in the direction indicated by x in the figure, which is substantially perpendicular to the optical path of the laser beam L, and the ultrasonic wave is generated from the lower surface 42 of the ultrasonic medium 40 and the other side. It enters into a wedge-shaped portion between the end face 44 and the end face 44, and is absorbed or trapped by the ultrasonic absorber 40a such as a thin lead plate provided on the end face 44.

【０００６】超音波はもちろん粗密波であるから、超音
波が通過する超音波媒体4071には光に対する屈折率の縞
模様が形成されてレーザ光Ｌに対して一種の回折格子と
して作用する。そこで、超音波の進行方向をその粗密波
の波面がレーザ光Ｌの方向に対し微小な角度θをもつよ
うにして置くと、図の電子スィッチ72のオン, つまりＱ
スィッチ60のオン状態では超音波の回折格子のブラッグ
回折によりレーザ光Ｌが本来の方向から図の２θで示す
方向に偏向されるので共振系内のレーザ発振が抑止され
る。この状態でＱスィッチ60をオフにすると、レーザ光
Ｌは本来の方向に進行してそれまでレーザ媒質10に蓄積
されていたエネルギが一気に放出され、急激なレーザ発
振が起こってジャイアントパルスが発生する。Since the ultrasonic waves are, of course, compressional waves, a stripe pattern having a refractive index for light is formed on the ultrasonic medium 4071 through which the ultrasonic waves pass, and acts as a kind of diffraction grating for the laser light L. Therefore, when the traveling direction of the ultrasonic wave is set so that the wavefront of the compression wave has a minute angle θ with respect to the direction of the laser light L, the electronic switch 72 in the figure is turned on, that is, Q.
In the ON state of the switch 60, the laser light L is deflected from the original direction by the Bragg diffraction of the ultrasonic diffraction grating in the direction indicated by 2θ in the figure, so that the laser oscillation in the resonance system is suppressed. When the Q switch 60 is turned off in this state, the laser light L travels in the original direction, the energy accumulated in the laser medium 10 until then is released at once, and a rapid laser oscillation occurs to generate a giant pulse. .

【０００７】以上のＱスィッチでも原理上はレーザ装置
を制御してパルス発振させることができるが、実際には
超音波による回折の効率がレーザ光Ｌの偏光状態に強く
依存するので、これだけでは急峻な波形をもつ強力なパ
ルスレーザ光は得られない。例えば、溶融石英の超音波
媒体40では偏光面が超音波の進行方向に対して平行な光
は垂直な場合に比べて回折効率が５分の１程度に低下す
るので、レーザ光Ｌが直線偏光である場合は別としてラ
ンダム偏光である場合は回折効率が低下して、レーザ出
力が上昇するにつれて急峻な波形のパルスレーザ光が得
られなくなって来るからである。In principle, the above Q switch can also control the laser device to cause pulse oscillation, but in reality, the efficiency of diffraction by the ultrasonic wave strongly depends on the polarization state of the laser light L, so that it is sharp. It is not possible to obtain a strong pulsed laser beam with a unique waveform. For example, in the ultrasonic wave medium 40 of fused silica, the diffraction efficiency of the light whose polarization plane is parallel to the traveling direction of the ultrasonic wave is reduced to about 1/5 as compared with the case where the light is perpendicular, so that the laser light L is linearly polarized. In the case of random polarization, the diffraction efficiency decreases, and as the laser output increases, pulse laser light having a steep waveform cannot be obtained.

【０００８】この問題の一つの解決法として、超音波媒
体40内にレーザ光Ｌとほぼ直角方向でかつ互いに直交す
る２方向に超音波を進行させることにより二次元回折格
子を形成して回折効率の偏光状態への依存性をなくす手
段が従来から知られている。このため、図８に示すよう
に超音波媒体40の上面41にも破線で示す別のトランスデ
ューサ51を取り付け、前述のトランスデューサ50と同時
にこれをオンオフさせながら前述のｘ方向のほかにｙ方
向にも超音波を進行させる。これにより超音波媒体40内
に超音波の粗密によるレーザ光Ｌの進行方向とほぼ直角
なxy面に沿って二次元回折格子が結晶構造のように立体
的に形成されて、レーザ光の偏光状態に無関係に強い回
折作用を及ぼし得るようになる。As one solution to this problem, a two-dimensional diffraction grating is formed by advancing ultrasonic waves in the ultrasonic medium 40 in two directions substantially perpendicular to the laser light L and orthogonal to each other, thereby forming a diffraction efficiency. Conventionally, a means for eliminating the dependence of the above on the polarization state has been known. Therefore, as shown in FIG. 8, another transducer 51, which is indicated by a broken line, is attached to the upper surface 41 of the ultrasonic medium 40. While the transducer 50 is turned on and off at the same time as the transducer 50, the transducer 51 is moved in the y direction in addition to the x direction. Propagate ultrasonic waves. As a result, a two-dimensional diffraction grating is three-dimensionally formed in the ultrasonic medium 40 along the xy plane substantially perpendicular to the traveling direction of the laser light L due to the density of the ultrasonic waves, like a crystal structure, and the polarization state of the laser light is changed. The strong diffraction effect can be exerted regardless of

【０００９】上述の問題のもう一つの解決法として、い
わゆるλ／４板を利用してレーザ光の偏光面を回折に有
利な方向に回転させた上でＱスィッチの超音波媒体に与
える手段が知られており、図９にこれをレーザ共振系内
のＱスィッチ付近のみを取り出して示す。周知のよう
に、このλ／４板はその内部で光が互いに速度の異なる
ｐ偏光とｓ偏光とに分かれて進行することを利用して光
の通過ごとにこれら２種の偏光間に４分の１波長に相当
する位相差を賦与するもので、図９に示すように１対の
λ／４板61と62をＱスィッチ60を相互間に挟み込むよう
にレーザ共振系のレーザ光Ｌの光路内に挿入する。Another solution to the above problem is to use a so-called λ / 4 plate to rotate the plane of polarization of the laser light in a direction advantageous for diffraction and then to give it to the ultrasonic medium of the Q switch. It is known, and this is shown in FIG. 9 by extracting only the vicinity of the Q switch in the laser resonance system. As is well known, this λ / 4 plate utilizes the fact that the light is divided into p-polarized light and s-polarized light having different velocities and travels inside the λ / 4 plate. The optical path of the laser light L of the laser resonance system is such that a pair of λ / 4 plates 61 and 62 are sandwiched between the Q switches 60 as shown in FIG. Insert inside.

【００１０】この図９の従来例では、レーザ光Ｌ中の超
音波媒体40内の超音波の進行方向に対して平行なため回
折されにくい偏光成分がλ／４板を２度通過した後には
その偏光面が90°回転されて、回折されやすい偏光角度
で超音波媒体40に与えられるので超音波媒体の回折効率
が高まり、従ってＱスィッチ60のレーザ発振に対する抑
止効果が高められる。In the conventional example of FIG. 9, since the polarized component which is difficult to diffract because it is parallel to the traveling direction of the ultrasonic wave in the ultrasonic medium 40 in the laser beam L passes through the λ / 4 plate twice, Since the plane of polarization is rotated by 90 ° and given to the ultrasonic medium 40 at a polarization angle which is easily diffracted, the diffraction efficiency of the ultrasonic medium is increased, and therefore the effect of suppressing the laser oscillation of the Q switch 60 is enhanced.

【００１１】[0011]

【発明が解決しようとする課題】上述のように、図８の
超音波直交方式のＱスィッチでは超音波媒体40内の回折
格子の回折効率を上げ、図９のλ／４板方式のＱスィッ
チではレーザ光Ｌの偏光成分を超音波媒体40により回折
されやすい偏光面に変えることにより、それぞれＱスィ
ッチの性能を高めることができるが、いずれの従来技術
にも以下のように若干の問題点がある。As described above, in the ultrasonic orthogonal Q-switch of FIG. 8, the diffraction efficiency of the diffraction grating in the ultrasonic medium 40 is increased, and the λ / 4 plate type Q-switch of FIG. 9 is used. Then, by changing the polarization component of the laser light L to a polarization plane that is easily diffracted by the ultrasonic medium 40, the performance of each Q switch can be improved. However, any of the conventional techniques has some problems as described below. is there.

【００１２】従来の超音波直交方式では、超音波媒体40
内に超音波の粗密による回折格子を正確に形成させて高
い回折効率を安定に維持するには、トランスデューサ50
と51をそれぞれｘ方向とｙ方向の粗密波を形成させるに
適した周波数で駆動し、かつそれらに対する電気的な駆
動状態を互いに関連付けて精密に制御する必要があるの
で、高周波電源と付属回路を二重に要するほか制御回路
が複雑化し、電気装置が大形化してレーザ装置の価格も
かなり高くつく問題がある。In the conventional ultrasonic orthogonal system, the ultrasonic medium 40
In order to accurately form a diffraction grating due to the density of ultrasonic waves inside and maintain high diffraction efficiency in a stable manner, the transducer 50
And 51 must be driven at frequencies suitable for forming compression waves in the x-direction and y-direction, respectively, and the electric drive states for them must be precisely controlled in association with each other. In addition to the double cost, the control circuit becomes complicated, the electric device becomes large, and the cost of the laser device becomes considerably high.

【００１３】また従来のλ／４板方式では、λ／４板が
小形の低コストのもので済む利点がある反面、各λ／４
板に２個の反射面があって１対のλ／４板ではレーザ共
振系に４個の反射面を持ち込むことになり、もちろん反
射面ごとにレーザ光Ｌが僅かずつでも損失されて行くの
で全部の反射面ではかなりの損失になって、このためレ
ーザ出力の低下が避けられない問題がある。The conventional λ / 4 plate method has an advantage that the λ / 4 plate is small and low-cost, but on the other hand, each λ / 4 plate
The plate has two reflecting surfaces, and a pair of λ / 4 plates would bring four reflecting surfaces into the laser resonance system, and of course, the laser light L would be lost even slightly for each reflecting surface. There is a considerable loss in all the reflecting surfaces, which causes a problem that the reduction of the laser output is unavoidable.

【００１４】本発明はかかる問題点を解決して、できる
だけ簡易な構成で高出力かつ急峻な波形のパルスレーザ
光を取り出し得るＱスィッチ制御レーザ装置を提供する
ことを目的とする。An object of the present invention is to solve the above problems and to provide a Q switch control laser device capable of extracting a pulsed laser light having a high output and a steep waveform with a structure as simple as possible.

【００１５】[0015]

【課題を解決するための手段】本願の第１発明によれ
ば、超音波Ｑスィッチの超音波媒体を平行な対向２面と
それらに対し所定の角度をなす斜面をもつ断面形状に形
成し、トランスデューサによる超音波を超音波媒体内で
互いに交差する２方向に進行させることによって上述の
目的が達成される。According to the first invention of the present application, the ultrasonic medium of the ultrasonic Q switch is formed into a cross-sectional shape having two parallel opposing surfaces and an inclined surface forming a predetermined angle with respect to them. The above-mentioned object is achieved by propagating ultrasonic waves by the transducer in two directions that intersect each other in the ultrasonic medium.

【００１６】この第１発明では、超音波媒体の対向２面
中の斜面と鋭角をなす１面の斜面との隣接部分にトラン
スデューサを設けて超音波を斜面により反射させ、ある
いは超音波媒体の斜面にトランスデューサを設けて超音
波を対向する２面により反射させるようにするのが有利
であり、いずれの態様でもトランスデューサは単一とさ
れる。また、超音波媒体の斜面と反対側の端面を従来と
同様に斜面に形成してこの斜端面に超音波吸収材を設
け、超音波媒体内を互いに交差する２方向に進行する超
音波をこれに吸収させるのがよい。In the first aspect of the present invention, a transducer is provided at a portion adjacent to the slope of the two opposing surfaces of the ultrasonic medium and one slope forming an acute angle to reflect ultrasonic waves by the slope, or the slope of the ultrasonic medium. It is advantageous to dispose a transducer on each of the two surfaces so that the ultrasonic waves are reflected by the two surfaces facing each other. In either aspect, the transducer is single. Further, the end surface of the ultrasonic medium opposite to the slant surface is formed into a slant surface as in the conventional case, and an ultrasonic absorbing material is provided on this slant end surface so that ultrasonic waves traveling in two directions intersecting each other in the ultrasonic medium can be formed. It is better to absorb it.

【００１７】本願の第２発明では、共振系を構成する１
対のレーザ光反射手段の少なくとも一方にレーザ光の偏
光面を回転させる機能をもつ光学的手段を用い、この光
学的手段により偏光面が回転されたレーザ光をＱスィッ
チの超音波媒体に通過させることにより前述の目的を達
成する。According to the second aspect of the present invention, the resonance system 1 is constructed.
At least one of the pair of laser light reflecting means is an optical means having a function of rotating the polarization plane of the laser light, and the laser light whose polarization plane is rotated by this optical means is passed through the ultrasonic medium of the Q switch. By doing so, the above-mentioned object is achieved.

【００１８】この第２発明では、偏光面回転用の光学的
手段としてレーザ光に対して４分の１波長の位相差を賦
与するλ／４板やレーザ光を所定角度で全反射させる平
行な対向２面を備える斜方プリズム等を用いるのが有利
である。また、超音波媒質の側面をレーザ光に対する少
なくとも部分的な反射面に形成し、この側面を他方のレ
ーザ光反射手段として用いるのが有利である。さらに
は、超音波媒体に所定の面角で互いに交わる１対の側面
を設けるようにすれば、これら両側面でレーザ光を順次
に全反射させながらその偏光面を回転させる機能を超音
波媒体に賦与することができる。In the second invention, a λ / 4 plate for imparting a phase difference of ¼ wavelength to the laser light as an optical means for rotating the plane of polarization and a parallel plate for totally reflecting the laser light at a predetermined angle. It is advantageous to use an orthorhombic prism having two opposite surfaces. Further, it is advantageous that the side surface of the ultrasonic medium is formed as at least a partial reflection surface for the laser light, and this side surface is used as the other laser light reflecting means. Furthermore, if the ultrasonic medium is provided with a pair of side surfaces that intersect each other at a predetermined surface angle, the ultrasonic medium has a function of rotating the polarization plane while sequentially totally reflecting the laser light on both side surfaces. Can be granted.

【００１９】本願の第３発明ではレーザ媒質にスラブ状
に形成された光学結晶を用い、その細長い平行な対向２
面でレーザ光を繰り返し全反射させながらその偏光面を
回転させる機能をレーザ媒質に持たせることにより、さ
らに第４発明では超音波媒体の超音波の進行方向に沿う
表面をレーザ光に対する少なくとも部分的な反射面，す
なわち全反射面や部分反射面に形成し、これをレーザ共
振系を構成する一方のレーザ光反射手段，すなわち全反
射ミラーや出力ミラーとして用いることによりそれぞれ
前述の目的を達成する。なお、これらの本願発明の実施
に当たっては、第１から第３までの発明に上述の第４発
明を組み合わせるのがレーザ装置の構成を簡易化する上
で非常に有利である。In the third invention of the present application, an optical crystal formed in a slab shape is used as the laser medium, and the slender parallel facing 2
By providing the laser medium with the function of rotating the polarization plane while repeatedly totally reflecting the laser light on the surface, the surface of the ultrasonic medium along the traveling direction of the ultrasonic wave is at least partially exposed to the laser light. The above-mentioned objects are achieved by forming the reflective surface, that is, a total reflection surface or a partial reflection surface, and using it as one of the laser light reflecting means constituting the laser resonance system, that is, a total reflection mirror or an output mirror. In implementing these inventions of the present application, it is very advantageous to combine the above-mentioned fourth invention with the first to third inventions in order to simplify the configuration of the laser apparatus.

【００２０】[0020]

【作用】上述の第１発明では、超音波媒体を平行な対向
２面のほかそれらに対し所定の角度をなす斜面をもつ断
面形状に形成することにより、対向２面の一方や斜面の
上に設けた単一のトランスデューサから超音波媒体に注
入される超音波が斜面や対向２面の相互間で反射されな
がら常に互いに交差する２方向に進行するので、従来の
ように２個のトランスデューサを設けてそれらに対する
電気的な駆動状態を互いに関連付けて精密に制御する必
要がなくなり、超音波媒体内に交差超音波の粗密波によ
る回折格子を安定に形成してレーザ光に対する回折効率
を向上し、Ｑスィッチの性能を高めることができる。In the first aspect of the invention described above, the ultrasonic medium is formed into a cross-sectional shape having two parallel opposing surfaces and an inclined surface forming a predetermined angle with respect to them. Since the ultrasonic wave injected from the single transducer provided into the ultrasonic medium travels in two directions that always intersect with each other while being reflected between the inclined surface and the opposite two surfaces, two transducers are provided as in the conventional case. Therefore, it is no longer necessary to precisely control the electrical driving states for them by associating them with each other, and a diffraction grating by the compressional waves of crossed ultrasonic waves is stably formed in the ultrasonic medium to improve the diffraction efficiency for laser light, The performance of the switch can be improved.

【００２１】第２および第３発明は、いずれもレーザ光
Ｌの偏光成分の偏光面を超音波媒体によって回折されや
すいように回転させるものである。すなわち、第２発明
では共振系を構成する１対のレーザ光反射手段の少なく
とも一方にレーザ光の偏光面を回転させる機能をもつ光
学的手段を用い、第３発明ではレーザ媒質にスラブ状に
形成された光学結晶を用いてその細長い平行な対向２面
でレーザ光を繰り返し全反射させながらその偏光面を回
転させることにより、いずれの場合にも従来の超音波媒
体を挟むλ／４板対のように余分な反射面をレーザ共振
系内に組み込む必要をなくし、レーザ装置の構成を簡易
化しながら共振系内のレーザ光の損失を減少させて高効
率発振，従って高パルス出力を可能にするものである。In both the second and third inventions, the plane of polarization of the polarization component of the laser light L is rotated so that it is easily diffracted by the ultrasonic medium. That is, in the second invention, at least one of the pair of laser light reflecting means forming the resonance system is an optical means having a function of rotating the polarization plane of the laser light, and in the third invention, the laser medium is formed in a slab shape. By rotating the polarization plane while repeatedly totally reflecting the laser light on the two elongated parallel opposing surfaces using the optical crystal thus prepared, in any case, the conventional λ / 4 plate pair sandwiching the ultrasonic medium is formed. As described above, it is possible to reduce the loss of laser light in the resonance system while simplifying the structure of the laser device by eliminating the need to incorporate an extra reflection surface in the laser resonance system, thus enabling high-efficiency oscillation, and thus high pulse output. Is.

【００２２】さらに、第４発明は、超音波媒体の超音波
の進行方向に沿う表面をレーザ光に対する少なくとも部
分的な反射面に形成し、これをレーザ共振系を構成する
一方のレーザ光反射手段に利用することにより、レーザ
装置の構成をより簡易化するとともに、反射面を減少さ
せて発振効率を一層向上させるものである。Further, in the fourth invention, the surface of the ultrasonic medium along the traveling direction of the ultrasonic wave is formed as at least a partial reflecting surface for the laser light, and this is one laser light reflecting means constituting a laser resonance system. In addition to simplifying the structure of the laser device, the number of reflecting surfaces is reduced to further improve the oscillation efficiency.

【００２３】[0023]

【実施例】以下、図を参照しながら本願発明の実施例を
説明する。図１と図２は第１発明の実施例，図３は第２
発明の実施例、図４〜図６は第２発明と第４発明とを組
み合わせた実施例，図７は第３発明の実施例をそれぞれ
示し、いずれの実施例でも図８と図９に対応する部分に
同符号が付されているので、以下の説明中の前との重複
部分はすべて省略することとする。Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the first invention, and FIG. 3 shows a second embodiment.
Embodiments of the invention, FIGS. 4 to 6 show embodiments in which the second and fourth inventions are combined, and FIG. 7 shows an embodiment of the third invention, and each embodiment corresponds to FIGS. 8 and 9. Since the same reference numerals are given to the portions to be described, all the overlapping portions with those in the following description will be omitted.

【００２４】図１の第１発明の実施例では、同図(a) に
示すようにＱスィッチ60の溶融石英ないし石英ガラス等
からなる超音波媒体40の一方の端面が斜面43に形成され
る。この斜面43の角度は、同図(b) 超音波媒体40を光学
軸と直角方向に切った断面に示すように、超音波媒体40
の互いに平行な上面41と下面42に対しこの実施例では45
°とするのがよく、この斜面43の真上の上面41の端部に
リチウムナイオベートの薄片等からなるトランスデュー
サ50が接着される。In the embodiment of the first invention of FIG. 1, one end face of the ultrasonic medium 40 made of fused quartz or quartz glass of the Q switch 60 is formed on the slope 43 as shown in FIG. 1 (a). . The angle of the inclined surface 43 is determined by the ultrasonic medium 40 as shown in the section (b) of the ultrasonic medium 40 taken in the direction perpendicular to the optical axis in FIG.
In this embodiment, the upper surface 41 and the lower surface 42 are parallel to each other.
The angle is preferably set to 0 °, and the transducer 50 made of a thin piece of lithium niobate or the like is bonded to the end of the upper surface 41 just above the slope 43.

【００２５】このトランスデューサ50から超音波媒体40
内に注入される超音波は、同図(b)のようにｙ方向に進
行した後に斜面43により直角方向に反射され、ｘ方向に
進行した後に従来と同様に斜端面44に取り付けられた超
音波吸収材40ａによって吸収される。図のように、超音
波媒体40内の斜面43の近傍に２方向に進行する超音波の
交差領域，この例では直交領域が形成され、その粗密に
より前述の二次元的な回折格子ができるので、この領域
にレーザ光Ｌを図１(a) のように通過させる。なお、こ
の第１発明でも超音波媒体40はその光学軸がレーザ光Ｌ
に対し微小角θをなすように置かれ、Ｑスィッチ60のオ
ン状態でレーザ光Ｌを図の２θの方向にそらしてレーザ
発振を抑止する。レーザ媒質10を挟むレーザ光反射手段
としての全反射ミラー31と部分反射ミラー32によりレー
ザ共振系が構成され、この共振系内にＱスィッチ60が挿
入され、部分反射ミラー32側から出力パルスレーザ光Lo
が取り出されるのも従来の図８の場合と同じである。From this transducer 50 to the ultrasonic medium 40
The ultrasonic waves injected into the inside of the ultrasonic wave are propagated in the y direction as shown in FIG. 7B, then reflected in the right angle direction by the slope 43, and after advancing in the x direction, they are attached to the slope end face 44 as in the conventional case. It is absorbed by the sound wave absorber 40a. As shown in the figure, an intersection region of ultrasonic waves traveling in two directions, in this example, an orthogonal region is formed in the vicinity of the inclined surface 43 in the ultrasonic medium 40, and the two-dimensional diffraction grating described above can be formed due to its density. The laser light L is passed through this area as shown in FIG. 1 (a). Also in the first invention, the ultrasonic medium 40 has the optical axis of the laser beam L.
On the other hand, the laser beam L is placed so as to form a small angle θ, and the laser light L is deflected in the direction of 2θ in the figure while the Q switch 60 is in the ON state to suppress laser oscillation. A laser resonance system is constituted by a total reflection mirror 31 and a partial reflection mirror 32 which serve as a laser light reflecting means sandwiching the laser medium 10, and a Q switch 60 is inserted into this resonance system, and an output pulse laser beam is output from the partial reflection mirror 32 side. Lo
Is taken out in the same manner as in the conventional case of FIG.

【００２６】図２に第１発明の異なる実施例を超音波媒
体40の断面により示す。この実施例ではトランスデュー
サ50が斜面43に設けられる。これにより超音波媒体40に
注入される超音波はその内部を図のようにジグザグ状に
進んだ後に超音波吸収材40ａにより吸収され、この間に
超音波媒体40の断面のほぼ全域に超音波の交差領域が図
のように形成されるので、この実施例では超音波媒体40
に与えるレーザ光Ｌのビーム径を図１の実施例よりも大
きくできる利点が得られる。なお、この実施例における
超音波の交差領域内の進行方向はｘおよびｙ方向から傾
いており、この傾き角度はもちろん斜面43の斜角αによ
り決まる。この斜角αは、ふつうは45°とすることでよ
いが、必ずしもこれに正確に合わせる必要はなく、図１
の実施例の場合より広い範囲の選択が可能である。FIG. 2 shows a cross section of an ultrasonic medium 40 according to a different embodiment of the first invention. In this embodiment, the transducer 50 is provided on the slope 43. As a result, the ultrasonic waves injected into the ultrasonic medium 40 travel inside the ultrasonic medium 40 in a zigzag shape as shown in the figure and are then absorbed by the ultrasonic absorber 40a. Since the intersection area is formed as shown, the ultrasonic medium 40 is used in this embodiment.
The advantage that the beam diameter of the laser light L given to the above can be made larger than that of the embodiment of FIG. It should be noted that the traveling direction in the crossing region of the ultrasonic waves in this embodiment is inclined from the x and y directions, and this inclination angle is of course determined by the inclination angle α of the slope 43. This slant angle α may normally be set to 45 °, but it is not necessary to exactly match this angle, and FIG.
A wider range can be selected than in the case of the above embodiment.

【００２７】図１と図２の第１発明のいずれの実施例で
も、Ｑスィッチ60に単一のトランスデューサ50を設けて
簡単な駆動回路から付勢するだけで超音波媒体40内に超
音波の交差領域を安定に形成して、レーザ光Ｌの偏光状
態に依存しない高い回折効率を達成してＱスィッチ60の
性能を高めることができる。In both the first and second embodiments of the invention shown in FIGS. 1 and 2, it is possible to provide ultrasonic waves in the ultrasonic medium 40 by providing a single transducer 50 in the Q switch 60 and energizing it by a simple drive circuit. It is possible to stably form the intersecting region, achieve high diffraction efficiency that does not depend on the polarization state of the laser light L, and improve the performance of the Q switch 60.

【００２８】図３に第２発明の一実施例を示す。この実
施例ではレーザ媒質10を含むレーザ共振系を構成する１
対のレーザ光反射手段としてレーザ光Ｌの偏光面の回転
機能をもつλ／４板33と34とを用い、共振系内のレーザ
光Ｌの光路に超音波媒体40の一端面のみにトランスデュ
ーサ50を備える最も簡単な構造の超音波Ｑスィッチ60を
挿入する。１対のレーザ光反射手段中のλ／４板33は外
側面33ａにレーザ光Ｌに対し高反射性，内側面33ｂに無
反射性のコーティングをそれぞれ施して共振系の全反射
ミラーの役目を持たせ、λ／４板34は外側面34ａにふつ
うは５〜20％の部分反射性，内側面34ｂに無反射性のコ
ーティングをそれぞれ施して出力パルスレーザ光Loを取
り出す出力ミラーの役目を持たせる。FIG. 3 shows an embodiment of the second invention. In this embodiment, a laser resonance system including a laser medium 10 is constructed 1
The λ / 4 plates 33 and 34 having a function of rotating the plane of polarization of the laser light L are used as a pair of laser light reflecting means, and the transducer 50 is provided only on one end surface of the ultrasonic medium 40 in the optical path of the laser light L in the resonance system. Insert the ultrasonic Q-switch 60 with the simplest structure including. The λ / 4 plate 33 in the pair of laser light reflecting means functions as a total reflection mirror of a resonance system by coating the outer surface 33a with high reflectivity for the laser light L and the inner surface 33b with non-reflective coating. The λ / 4 plate 34 serves as an output mirror for extracting the output pulse laser light Lo by applying a coating of 5 to 20% partial reflection on the outer surface 34a and a non-reflective coating on the inner surface 34b. Let

【００２９】この図３のレーザ装置では、Ｑスィッチ60
をλ／４板33の方に向けて通過したレーザ光Ｌの回折効
率の低い偏光成分はλ／４板33内を往復する間に回折効
率の高い偏光成分に変換され、逆にＱスィッチ60をλ／
４板34の方に向けて通過したレーザ光Ｌの回折効率の低
い偏光成分もλ／４板34内を往復する間に回折効率の高
い偏光成分に変換されてそれぞれＱスィッチ60に戻る。
従って、レーザ光Ｌがレーザ共振系内を繰り返して往復
する間には回折効率の高い偏光成分のみにほぼ揃えられ
るので、簡単な構造のＱスィッチ60でも高性能で使用し
て急峻な波形の出力パルスレーザ光Loを取り出すことが
できる。また、図９の従来例よりレーザ共振系内の反射
面の総数が少ないのでレーザ光Ｌの損失が減少し、レー
ザ装置を高効率発振させて高出力化することができる。In the laser device of FIG. 3, the Q switch 60
Of the laser light L passing through the λ / 4 plate 33 toward the λ / 4 plate 33, the polarized component having low diffraction efficiency is converted into the polarized component having high diffraction efficiency while reciprocating in the λ / 4 plate 33, and conversely the Q switch 60. Λ /
The polarized light component of low diffraction efficiency of the laser light L passing toward the four plate 34 is also converted into the polarized light component of high diffraction efficiency while reciprocating in the λ / 4 plate 34 and returns to the Q switch 60.
Therefore, while the laser beam L is repeatedly reciprocating in the laser resonance system, it is almost aligned with only the polarization component having high diffraction efficiency, and even the Q switch 60 having a simple structure can be used with high performance to output a steep waveform. The pulsed laser light Lo can be extracted. Further, since the total number of reflecting surfaces in the laser resonance system is smaller than that in the conventional example of FIG. 9, the loss of the laser light L is reduced, and the laser device can be oscillated with high efficiency to achieve high output.

【００３０】図４に第２発明に第４発明の超音波媒体40
の表面を反射面に形成して共振系のレーザ光反射手段と
して利用する構成を組み合わせた実施例を示す。同図
(a) の構成図に示すように、この実施例ではレーザ共振
系の１対のレーザ光反射手段中の一方のみ, 図の例では
出力側にレーザ光Ｌに対して回転機能をもつλ／４板34
を用いて回折に不利なその偏光成分を有利な偏光面に変
換させ、Ｑスィッチ60の超音波媒体40の側面45にレーザ
光Ｌに対し高反射性のコーティングを施して他方のレー
ザ光反射手段, 図の例では全反射ミラーとして利用す
る。FIG. 4 shows an ultrasonic medium 40 according to the second invention to the fourth invention.
An example will be shown in which the surface is formed as a reflecting surface and is used as a laser light reflecting means of a resonance system. Same figure
As shown in the configuration diagram of (a), in this embodiment, only one of the pair of laser light reflecting means of the laser resonance system, in the example of the figure, λ / having a rotation function for the laser light L is provided on the output side. 4 plates 34
Is used to convert the polarization component, which is disadvantageous to diffraction, into an advantageous polarization plane, and the side surface 45 of the ultrasonic medium 40 of the Q switch 60 is coated with a highly reflective laser light L to provide the other laser light reflection means. In the example shown, it is used as a total reflection mirror.

【００３１】この全反射性の超音波媒体40の側面45はＱ
スィッチ60のオフ時にレーザ光Ｌを入射方向に正確に送
り返す必要があるので、同図(b) の超音波媒体40の断面
図に示すようにレーザ光Ｌに対し垂直に置かれる。しか
し、Ｑスィッチ60のオン時にレーザ光Ｌを図の２θの方
向に偏向させるには超音波媒体40内の超音波の波面にそ
れに対する僅かな角度を持たせる必要があるので、超音
波媒体40の端面43ａに図示のようにレーザ光Ｌの方向に
対し微小角θを持たせてトランスデューサ50を取り付け
る。The side surface 45 of the ultrasonic medium 40 having total internal reflection is Q
When the switch 60 is turned off, it is necessary to accurately send the laser beam L back in the incident direction, so that the laser beam L is placed perpendicular to the laser beam L as shown in the sectional view of the ultrasonic medium 40 in FIG. However, in order to deflect the laser light L in the direction of 2θ in the figure when the Q switch 60 is turned on, it is necessary to make the wavefront of the ultrasonic wave in the ultrasonic medium 40 have a slight angle with respect to it. The transducer 50 is attached such that the end face 43a of the laser has a small angle θ with respect to the direction of the laser beam L as shown in the figure.

【００３２】以上のように構成された図４の実施例で
は、Ｑスィッチ60の超音波媒体40内を側面45の方に通過
したレーザ光Ｌに対しては偏光面の回転機能はないが、
逆方向に通過したレーザ光Ｌはλ／４板34によりその偏
光面が回転されて超音波媒体40に戻って来るので、レー
ザ光Ｌはレーザ共振系内を繰り返して往復する内に回折
効率の高い偏光成分にほぼ揃えられて行き、図３の実施
例に近い高い回折効率が達成される。なお、この図４の
実施例では、図３のλ／４板33が省略されるのでレーザ
装置の構成が簡単になり、かつ反射面の総数も減少する
ので図３の実施例よりさらに高効率の,従って高出力の
レーザ発振が可能になる。In the embodiment of FIG. 4 configured as described above, there is no function of rotating the polarization plane for the laser light L which has passed through the ultrasonic medium 40 of the Q switch 60 toward the side surface 45.
Since the polarization plane of the laser light L that has passed in the opposite direction is rotated by the λ / 4 plate 34 and returns to the ultrasonic medium 40, the laser light L is repeatedly reciprocated in the laser resonance system and the diffraction efficiency of the laser light L increases. The polarized light components are almost aligned with each other, and high diffraction efficiency close to that of the embodiment of FIG. 3 is achieved. In the embodiment of FIG. 4, since the λ / 4 plate 33 of FIG. 3 is omitted, the structure of the laser device is simplified and the total number of reflecting surfaces is reduced, so that the efficiency is higher than that of the embodiment of FIG. Therefore, high power laser oscillation becomes possible.

【００３３】図５に示す第２発明の実施例では、レーザ
共振系の一方のレーザ光反射手段にレーザ光Ｌに対して
偏光回転機能を備える斜方プリズムを用い、かつ第４発
明と組み合わせる。すなわち、同図(a) の構成図に示す
ようにＱスィッチ60の超音波媒体40の全反射性の側面45
を他方のレーザ光反射手段に用いるのは図４と同じであ
るが、出力パルスレーザ光Loを取り出す側のレーザ光反
射手段としていわゆるフレネルの斜方プリズム35を用い
る。この斜方プリズム35は、光を全反射させるとよく知
られているようにそのｐ偏光成分とｓ偏光成分の間に位
相差が発生するのを利用して偏光面を回転させるもの
で、斜方プリズム35を構成するガラス等の光学媒体の屈
折率を例えば1.52とすると全反射面に対する入射角が5
5.5°または47.5°の場合に１回の全反射ごとにｐ偏光
成分とｓ偏光成分の間にπ／４だけの位相差が発生す
る。In the embodiment of the second invention shown in FIG. 5, an oblique prism having a polarization rotation function for the laser light L is used as one of the laser light reflecting means of the laser resonance system, and is combined with the fourth invention. That is, as shown in the configuration diagram of FIG. 1 (a), the total reflection side surface 45 of the ultrasonic medium 40 of the Q switch 60 is provided.
4 is used for the other laser beam reflecting means, but a so-called Fresnel's orthorhombic prism 35 is used as the laser beam reflecting means for extracting the output pulsed laser beam Lo. As is well known to totally reflect light, the orthorhombic prism 35 rotates a polarization plane by utilizing a phase difference between the p-polarized component and the s-polarized component. Assuming that the refractive index of an optical medium such as glass forming the rectangular prism 35 is 1.52, the incident angle with respect to the total reflection surface is 5
In the case of 5.5 ° or 47.5 °, a phase difference of π / 4 occurs between the p-polarized component and the s-polarized component for each total reflection.

【００３４】そこで、図５(b) のように斜方プリズム35
を縦断面が平行四辺形になるように形成してその端面35
ａと35ｂをレーザ光Ｌの入出射面, 斜めの側面35ｃと35
ｄを全反射面としてそれぞれ用い、側面35ｃと35ｄの傾
きをレーザ光Ｌの全反射角が上述の例えば55.5°になる
ようにし、かつレーザ光Ｌを図示のように２回全反射さ
せるようにする。この斜方プリズム35はその内部をレー
ザ光Ｌが往復するつど４回全反射させるから、前述のλ
／４板のいわば２枚分と同等な偏光回転機能を果たし、
しかも全反射により偏光を回転させるのでレーザ光Ｌの
損失がそれより少なくて済む。Therefore, as shown in FIG. 5B, the orthorhombic prism 35 is used.
Is formed so that its longitudinal section becomes a parallelogram, and its end face 35
a and 35b are the entrance and exit faces of the laser light L, and the oblique side faces 35c and 35
d is used as a total reflection surface, the inclinations of the side surfaces 35c and 35d are set so that the total reflection angle of the laser light L is, for example, 55.5 ° described above, and the laser light L is totally reflected twice as illustrated. To do. This orthorhombic prism 35 totally reflects the laser light L four times in each direction, so that the above-mentioned λ
A polarization rotation function equivalent to that of two / 4 plates is achieved,
Moreover, since the polarized light is rotated by total reflection, the loss of the laser light L can be less than that.

【００３５】なお、図５の実施例では斜方プリズム35を
レーザ装置の出力側に用いるので、端面35ａにレーザ光
Ｌに対し部分反射性, 端面35ｂに無反射性のコーティン
グをそれぞれ施す。また、この実施例では超音波媒体40
内で超音波が進行するｘ方向に平行なレーザ光Ｌの偏光
成分を斜方プリズム35内でｐ偏光とｓ偏光に分割する必
要があるので、斜方プリズム35を図５(a) と(c) に示す
ようにその端面35ｂの中心線ないし長手軸方向がｘ方向
に対し45°の角度をなす姿勢に置く。Since the orthorhombic prism 35 is used on the output side of the laser device in the embodiment shown in FIG. 5, the end face 35a is provided with a partial reflection for the laser light L and the end face 35b is provided with a non-reflection coating. Further, in this embodiment, the ultrasonic medium 40
Since it is necessary to divide the polarization component of the laser light L parallel to the x direction in which the ultrasonic wave propagates into the p-polarized light and the s-polarized light within the orthorhombic prism 35, the orthorhombic prism 35 is formed as shown in FIG. As shown in c), the end face 35b is placed in a posture in which the center line or the longitudinal axis direction forms an angle of 45 ° with the x direction.

【００３６】以上のように構成された図５の実施例は、
図４のλ／４板34を斜方プリズム35により置き換えただ
けなので超音波媒体40のレーザ光Ｌに対する回折効率お
よびレーザ装置の発振効率等の性能は図４の実施例と同
等かそれより若干優れ、かつλ／４板34よりも斜方プリ
ズム35の方が安価につく利点がある。The embodiment of FIG. 5 constructed as above is as follows:
Since the λ / 4 plate 34 in FIG. 4 is simply replaced by the orthorhombic prism 35, the performances such as the diffraction efficiency of the ultrasonic medium 40 for the laser light L and the oscillation efficiency of the laser device are the same as or slightly higher than those of the embodiment of FIG. The prism prism 35 is excellent and has the advantage of being cheaper than the λ / 4 plate 34.

【００３７】図６に超音波媒体40にレーザ光Ｌに対する
偏光回転機能を持たせた第２発明の実施例を第４発明と
組み合わせた態様で示す。この実施例では、超音波媒体
40の図の手前の面が互いに所定の面角で交わる１対の側
面45ａと45ｂからなる屋根状に形成され、レーザ光Ｌは
これらの側面45ａと45ｂで順次に全反射されて図の例で
は逆方向に折り返される。反対側の側面46にはレーザ光
Ｌに対して無反射性のコーティングが施されるが、上の
ように折り返されたレーザ光Ｌが当たる面部分である側
面47には高反射性コーティングが施される。FIG. 6 shows an embodiment of the second invention in which the ultrasonic medium 40 is provided with a polarization rotation function for the laser light L in a mode combined with the fourth invention. In this example, the ultrasonic medium
The front surface of the figure of 40 is formed in a roof shape consisting of a pair of side surfaces 45a and 45b intersecting each other at a predetermined surface angle, and the laser light L is sequentially totally reflected by these side surfaces 45a and 45b. Then it is folded back in the opposite direction. The side surface 46 on the opposite side is coated with a non-reflective coating for the laser light L, but the side surface 47, which is the surface portion hit by the laser light L folded back as described above, is coated with a highly reflective coating. To be done.

【００３８】上述のように形成された超音波媒体40の１
対の側面45ａと45ｂが果たす役割は図５の斜方プリズム
35の２個の側面35ｃと35ｄと同様であり、レーザ光Ｌを
往復のつどに４回の全反射して２枚のλ／４板とほぼ同
等な偏光回転機能を果たす。この際のレーザ光Ｌの側面
35ｃや35ｄへの入射角は前述の55.5°や47.5°の条件を
満たすよう例えば47.5°に設定され、上述のようにレー
ザ光Ｌを逆方向に折り返させるには両側面35ｃと35ｄが
交わる面角を容易にわかるようにその倍の95°にすれば
よいことになる。One of the ultrasonic media 40 formed as described above
The role of the pair of side surfaces 45a and 45b is the orthorhombic prism shown in FIG.
Similar to the two side surfaces 35c and 35d of 35, the laser light L is totally reflected four times for each round trip, and achieves a polarization rotation function almost equivalent to that of two λ / 4 plates. Side surface of laser light L at this time
The angle of incidence on 35c and 35d is set to, for example, 47.5 ° so as to satisfy the above-mentioned conditions of 55.5 ° and 47.5 °, and as described above, in order to turn the laser beam L in the opposite direction, the side surfaces 35c and 35d intersect The angle should be doubled to 95 ° so that the angle can be easily seen.

【００３９】なお、この実施例でも超音波媒体40内の超
音波の進行方向に平行なレーザ光Ｌの偏光成分をその側
面35ｃや35ｄにおける全反射時にｐ偏光とｓ偏光に分割
する必要があるため、トランスデューサ50の取り付け用
端面43ｂに図４のように45°の傾斜が付けられる。従っ
て、超音波が互いに平行な上面41と下面42の間で反射さ
れて、超音波媒体40の内部に図２と同様な超音波の直交
領域が形成されるのでレーザ光Ｌに対する回折効率が一
層高められる。超音波媒体40の上述の全反射性側面47は
レーザ共振系を構成する一方のレーザ光反射手段の役目
を果たす。もう一方の出力側のレーザ光反射手段には図
８と同様に部分反射性の出力ミラー32を用いてもよい
が、この実施例では図３や図４の実施例の場合と同様に
λ／４板34が用いられている。Also in this embodiment, it is necessary to split the polarization component of the laser light L parallel to the traveling direction of the ultrasonic wave in the ultrasonic medium 40 into p-polarized light and s-polarized light at the time of total reflection on the side surfaces 35c and 35d. Therefore, the mounting end surface 43b of the transducer 50 is inclined by 45 ° as shown in FIG. Therefore, the ultrasonic waves are reflected between the upper surface 41 and the lower surface 42 which are parallel to each other, and an orthogonal region of the ultrasonic waves as in FIG. 2 is formed inside the ultrasonic medium 40, so that the diffraction efficiency for the laser light L is further improved. To be enhanced. The above-mentioned total reflection side surface 47 of the ultrasonic medium 40 serves as one of the laser light reflecting means forming the laser resonance system. A partially reflective output mirror 32 may be used for the other laser light reflecting means on the output side as in the case of FIG. 8, but in this embodiment, as in the case of the embodiments of FIGS. 3 and 4, λ / Four plates 34 are used.

【００４０】このように構成された図６の実施例では、
レーザ光Ｌに対する偏光回転機能が図２から図６までの
実施例より完全で、かつ超音波媒体40内の超音波の直交
領域に形成される二次元回折格子によりレーザ光Ｌを回
折させるので、Ｑスィッチ60のレーザ光Ｌに対する回折
効率を一層高めてレーザ装置の発振効率およびパルス出
力をさらに向上することができる。In the embodiment of FIG. 6 thus constructed,
The polarization rotation function for the laser light L is more complete than that of the embodiment shown in FIGS. 2 to 6, and the laser light L is diffracted by the two-dimensional diffraction grating formed in the orthogonal region of the ultrasonic waves in the ultrasonic medium 40. The diffraction efficiency of the Q switch 60 with respect to the laser light L can be further enhanced to further improve the oscillation efficiency and pulse output of the laser device.

【００４１】図７に第４発明の実施例を示す。この第４
発明ではレーザ媒質11を図のようないわゆるスラブ状に
形成して、そのレーザ光Ｌに対する偏光回転機能を利用
することによりレーザ装置の構成を一層簡易化する。FIG. 7 shows an embodiment of the fourth invention. This 4th
In the present invention, the laser medium 11 is formed in a so-called slab shape as shown in the figure, and the polarization rotation function for the laser light L is utilized to further simplify the configuration of the laser device.

【００４２】スラブ形のレーザ媒質11は偏平な横断面を
もつ細長いＹＡＧ等の光学結晶で、ふつうは斜面である
その１対の端面11ａと11ｂからレーザ光Ｌを出入させ、
その内部を平行な細長い１対の対向面11ｃと11ｄで全反
射させながら図のようにジグザグ状に進行させる。レー
ザ光Ｌが全反射されるつど前述のようにそのｐ偏光とｓ
偏光の間に位相差が発生するから、全反射の角度と回数
を適切に設定することによりこのレーザ媒質11に強い偏
光回転機能を持たせることができる。The slab-shaped laser medium 11 is an optical crystal such as a slender YAG having a flat cross section, and the laser beam L is made to enter and exit from a pair of end faces 11a and 11b which are usually slopes.
The inside is made to travel in a zigzag shape as shown in the drawing while being totally reflected by a pair of elongated parallel facing surfaces 11c and 11d. Each time the laser light L is totally reflected, the p-polarized light and s
Since a phase difference occurs between polarized lights, it is possible to give the laser medium 11 a strong polarization rotation function by appropriately setting the angle and the number of total reflections.

【００４３】図７の実施例ではレーザ共振系の１対のレ
ーザ光反射手段に全反射ミラー31と部分反射性の出力ミ
ラー32が用いられており、Ｑスィッチ60はもちろんこれ
らにより構成される共振系内のレーザ光Ｌの光路に挿入
される。また、この第４発明では、Ｑスィッチ60の姿勢
をレーザ媒質11の全反射面である対向面11ｃや11ｄに対
し図のように45°傾けて、超音波媒体40内の超音波の進
行方向に平行なレーザ光Ｌの偏光成分をレーザ媒質11に
よる全反射時にｐ偏光とｓ偏光に分割するのがとくに有
利である。In the embodiment of FIG. 7, a total reflection mirror 31 and a partially reflective output mirror 32 are used as a pair of laser light reflecting means of the laser resonance system, and the Q switch 60 and the resonance constituted by them are of course used. It is inserted in the optical path of the laser light L in the system. Further, in the fourth invention, the attitude of the Q switch 60 is inclined by 45 ° with respect to the facing surfaces 11c and 11d, which are total reflection surfaces of the laser medium 11, as shown in the figure, and the traveling direction of the ultrasonic waves in the ultrasonic medium 40 is increased. It is especially advantageous to split the polarization component of the laser light L parallel to the p-polarized light and the s-polarized light at the time of total reflection by the laser medium 11.

【００４４】このように構成された図７の実施例では、
レーザ媒質11内の全反射角をレーザ光Ｌの偏光回転に最
も有利なように常に設定できるとは限らないが、レーザ
光Ｌが共振系内を１往復する間の全反射回数をふつうは
少なくとも20回取れるので、レーザ媒質11に充分な偏光
回転機能を持たせることができる。また図からわかるよ
うに、この第４発明はレーザ装置の全体構成を非常に簡
単にすることができ、かつレーザ媒質11にスラブ形を用
いるので高出力パルス発振にとくに適する利点を有す
る。In the embodiment of FIG. 7 thus constructed,
Although the total reflection angle in the laser medium 11 cannot always be set so as to be most advantageous for the polarization rotation of the laser light L, the number of total reflections during one round trip of the laser light L in the resonance system is usually at least. Since it can be taken 20 times, the laser medium 11 can have a sufficient polarization rotation function. Further, as can be seen from the figure, the fourth invention has an advantage that the whole structure of the laser device can be made very simple and the slab type is used for the laser medium 11, which is particularly suitable for high power pulse oscillation.

【００４５】以上例示した実施例に限らず、本願発明は
種々変形した態様や第１〜第４発明を適宜に組み合わせ
た態様で実施することができる。例えば、第４発明を用
いた図３〜図５の実施例では超音波媒体の側面をレーザ
光に対し全反射性としたが、これを部分反射性にしてＱ
スィッチを出力パルスレーザ光の取り出し側にも適用す
ることができる。The present invention is not limited to the above-exemplified embodiments, but can be carried out in variously modified modes and modes in which the first to fourth inventions are appropriately combined. For example, in the embodiment of FIGS. 3 to 5 using the fourth invention, the side surface of the ultrasonic medium is made totally reflective to the laser light, but this is made partially reflective and Q
The switch can also be applied to the extraction side of the output pulsed laser light.

【００４６】また、実施例では本願の第４発明をすべて
第２発明と組み合わせた態様で説明したが、これを単独
の形でないしは第１発明や第３発明と組み合わせた形で
適宜に実施して、レーザ装置の全体構成を簡単化できる
その効果を発揮させることができるのはもちろんであ
る。Further, in the embodiments, the fourth invention of the present application has been described in a mode in which it is combined with the second invention, but the invention is appropriately carried out not in a single form or in a form combined with the first invention and the third invention. Of course, it is possible to exert the effect of simplifying the overall configuration of the laser device.

【００４７】[0047]

【発明の効果】以上説明したとおり、本願の第１発明で
は、レーザ共振系内に配設した超音波Ｑスィッチの超音
波媒体を平行な対向２面とそれらと所定の角度をなす斜
面とをもつ断面形状に形成することにより、単一のトラ
ンスデューサから超音波媒体に注入した超音波をその斜
面や対向２面で反射させながら互いに交差する２方向に
進行させてその粗密波により回折効率のよい二次元回折
格子を形成させることができるので、(a) 従来のように
２個のトランスデューサを設ける必要をなくし、(b) ト
ランスデューサ相互間を互いに関連付けて電気的駆動状
態を精密制御する必要をなくしてトランスデューサ用の
駆動回路を簡単化し、(c) 単一のトランスデューサによ
って超音波媒体の内部に交差超音波の粗密波による回折
格子を非常に安定に形成することができ、(d) 従ってレ
ーザ光に対する回折効率を向上してＱスィッチの性能を
高めることができる。As described above, in the first invention of the present application, the ultrasonic medium of the ultrasonic Q switch arranged in the laser resonance system is provided with two parallel opposing surfaces and an inclined surface forming a predetermined angle with them. By forming the cross-sectional shape of the ultrasonic wave, the ultrasonic waves injected from the single transducer into the ultrasonic medium are caused to travel in two directions intersecting with each other while being reflected by the inclined surface or the two opposite surfaces, and the compression wave has high diffraction efficiency. Since a two-dimensional diffraction grating can be formed, (a) it is not necessary to provide two transducers as in the past, and (b) it is not necessary to associate the transducers with each other to precisely control the electric drive state. To simplify the drive circuit for the transducer, and (c) form a diffraction grating with crossing ultrasonic compression waves inside the ultrasonic medium very stably with a single transducer. It can be, it is possible to enhance the performance of the Q switch to improve the diffraction efficiency for thus the laser beam (d).

【００４８】本願の第２発明では、共振系を構成する１
対のレーザ光反射手段の少なくとも一方にレーザ光の偏
光面を回転させる機能をもつ光学的手段を用い、この光
学的手段により偏光面が回転されたレーザ光をＱスィッ
チの超音波媒体を通過させるようにしたので、(a) 従来
のＱスィッチ用にとくにλ／４板対を組み込む構成に比
べてレーザ装置の構成を簡易化し、(b) レーザ共振系内
の余分な反射面を省いてレーザ光の損失を減少させ、レ
ーザ装置を高効率かつ高パルス出力で発振させることが
できる。In the second invention of the present application, the resonance system 1
An optical means having a function of rotating the polarization plane of the laser light is used for at least one of the pair of laser light reflection means, and the laser light whose polarization plane is rotated by this optical means is passed through the ultrasonic medium of the Q switch. Therefore, (a) the structure of the laser device is simplified compared to the conventional structure for incorporating a λ / 4 plate pair for the Q switch, and (b) the laser by eliminating an extra reflection surface in the laser resonance system. It is possible to reduce light loss and oscillate the laser device with high efficiency and high pulse output.

【００４９】本願の第３発明では、レーザ媒質にスラブ
状の光学結晶を用いて、その細長い平行な対向２面でレ
ーザ光を繰り返し全反射させながらその偏光面を回転さ
せることにより、第２発明の(a) と(b) の効果に加え
て、(c) レーザ装置の全体構成を単純化してコストを下
げ、(d) スラブ形レーザ媒質の特質を利用してレーザ装
置を非常に高い出力でパルス発振させることができる。In the third invention of the present application, a slab-shaped optical crystal is used as the laser medium, and the plane of polarization is rotated while the laser light is repeatedly totally reflected by the two elongated parallel opposing surfaces. In addition to the effects of (a) and (b) in (1), (c) the overall structure of the laser device is simplified and the cost is reduced, and (d) the characteristics of the slab type laser medium are used to make the laser device have a very high output. Pulse oscillation can be performed with.

【００５０】本願の第４発明では、超音波媒体の超音波
の進行方向に沿う表面をレーザ光に対する全反射面や部
分反射面に形成してレーザ共振系を構成する一方のレー
ザ光反射手段に利用することにより、第２発明の(a) と
(b)の効果に加えて、(c) 上述の第１〜第３発明と組み
合わせて実施することにより、それらに特有の効果は発
揮させながらレーザ装置の全体構成を一層簡易化でき
る。In the fourth invention of the present application, the one surface of the ultrasonic medium along the traveling direction of the ultrasonic wave is formed as a total reflection surface or a partial reflection surface for the laser light to form one laser light reflection means. By utilizing,
In addition to the effect of (b), (c) By carrying out in combination with the above-described first to third inventions, it is possible to further simplify the overall configuration of the laser device while exhibiting the effects unique to them.

【００５１】以上のように本願発明は、超音波Ｑスィッ
チの性能を高めあるいはその性能を発揮させながら、い
ずれも小形かつ安価なレーザ装置により高発振効率で急
峻なパルス波形をもつ高出力のレーザパルス発振を可能
にするもので、レーザ装置の一層の発展と普及に貢献す
ることが期待される。As described above, according to the present invention, while the performance of the ultrasonic Q switch is enhanced or the performance thereof is exerted, a high output laser having a high oscillation efficiency and a steep pulse waveform is provided by a small and inexpensive laser device. It enables pulsed oscillation and is expected to contribute to the further development and spread of laser devices.

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

【図１】第１発明によるレーザ装置の実施例を示し、同
図(a) はその構成図、同図(b)はＱスィッチ用の超音波
媒体の断面図である。FIG. 1 shows an embodiment of a laser device according to the first invention, FIG. 1 (a) is a configuration diagram thereof, and FIG. 1 (b) is a sectional view of an ultrasonic medium for a Q switch.

【図２】第１発明の異なる実施例を示す超音波媒体の断
面図である。FIG. 2 is a sectional view of an ultrasonic medium showing a different embodiment of the first invention.

【図３】第２発明によるレーザ装置の実施例を示す構成
図である。FIG. 3 is a configuration diagram showing an embodiment of a laser device according to the second invention.

【図４】第２発明と第４発明とを組み合わせたレーザ装
置の実施例を示し、同図(a) はその構成図、同図(b) は
Ｑスィッチ用の超音波媒体の断面図である。FIG. 4 shows an embodiment of a laser device in which the second invention and the fourth invention are combined. FIG. 4A is a configuration diagram thereof, and FIG. 4B is a sectional view of an ultrasonic medium for a Q switch. is there.

【図５】第２発明と第４発明とを組み合わせたレーザ装
置の異なる実施例を示し、同図(a) はその構成図、同図
(b) は斜方プリズムの縦断面図、同図(c) はＱスィッチ
の超音波媒体と斜方プリズムの位置関係図である。FIG. 5 shows a different embodiment of a laser device in which the second invention and the fourth invention are combined, and FIG. 5 (a) is its configuration diagram, FIG.
(b) is a longitudinal sectional view of the orthorhombic prism, and (c) is a positional relationship diagram of the ultrasonic medium of the Q switch and the orthorhombic prism.

【図６】第２発明と第４発明とを組み合わせたレーザ装
置のさらに異なる実施例を示す構成図である。FIG. 6 is a configuration diagram showing a further different embodiment of the laser device in which the second invention and the fourth invention are combined.

【図７】第３発明によるレーザ装置の実施例を示す構成
図である。FIG. 7 is a configuration diagram showing an embodiment of a laser device according to the third invention.

【図８】従来技術によるレーザ装置の構成図である。FIG. 8 is a configuration diagram of a laser device according to a conventional technique.

【図９】異なる従来技術によるレーザ装置のＱスィッチ
付近の斜視図である。FIG. 9 is a perspective view around a Q switch of a laser device according to another conventional technique.

【符号の説明】[Explanation of symbols]

10 レーザ媒質 11 スラブ状のレーザ媒質 11ｃ スラブ状レーザ媒質の一方の対向面 11ｄ スラブ状レーザ媒質の他方の対向面 33 レーザ光反射手段としてのλ／４板 34 レーザ光反射手段としてのλ／４板 35 レーザ光反射手段としての斜方プリズム 40 超音波媒体 41 超音波媒体の平行な対向２面の一方としての上
面 42 超音波媒体の平行な対向２面の他方としての下
面 43 超音波媒体の斜面 45 レーザ光反射手段としての超音波媒体の側面 45ａ 超音波媒体の互いに交わる１対の側面の一方 45ｂ 超音波媒体の互いに交わる１対の側面の他方 47 レーザ光反射手段としての超音波媒体の側面な
いし側面部分 50 トランスデューサ 60 超音波Ｑスィッチ Ｌ レーザ光 Lo 出力パルスレーザ光10 laser medium 11 slab-shaped laser medium 11c one facing surface of the slab-shaped laser medium 11d other facing surface of the slab-shaped laser medium 33 λ / 4 plate as laser light reflecting means 34 λ / 4 as laser light reflecting means Plate 35 Orthogonal prism 40 as laser light reflecting means 40 Ultrasonic medium 41 Upper surface as one of two parallel opposing surfaces of ultrasonic medium 42 Lower surface 43 as the other of two opposing parallel surfaces of ultrasonic medium 43 Slope 45 Side 45a of ultrasonic medium as laser light reflecting means One of a pair of side surfaces of ultrasonic medium intersecting each other 45b Another side of pair of side surfaces of ultrasonic medium intersecting each other 47 Of ultrasonic medium as laser light reflecting means Side or side part 50 Transducer 60 Ultrasonic Q switch L laser light Lo output pulse laser light

Claims (10)

【特許請求の範囲】[Claims] 【請求項１】レーザ媒質を含むレーザ共振系内に配設し
た超音波Ｑスィッチを制御してパルスレーザ光を発生さ
せるレーザ装置であって、超音波Ｑスィッチの超音波媒
体を平行な対向２面とそれらに対し所定の角度をなす斜
面をもつ断面形状に形成し、トランスデューサによる超
音波を超音波媒体内で互いに交差する２方向に進行させ
るようにしたことを特徴とするＱスィッチ制御レーザ装
置。1. A laser device for generating a pulsed laser beam by controlling an ultrasonic wave Q switch arranged in a laser resonance system including a laser medium, the ultrasonic wave medium of the ultrasonic wave Q switch being opposed to each other in parallel. A Q-switch control laser device characterized in that it is formed in a cross-sectional shape having planes and slopes forming a predetermined angle with respect to the planes, and that ultrasonic waves produced by a transducer are made to travel in two directions intersecting each other in an ultrasonic medium. . 【請求項２】請求項１に記載のレーザ装置において、超
音波媒体の対向２面中の斜面と鋭角をなす１面の斜面と
の隣接部分にトランスデューサを設け、それによる超音
波を斜面において反射させるようにしたことを特徴とす
るＱスィッチ制御レーザ装置。2. The laser device according to claim 1, wherein a transducer is provided at a portion adjacent to a slope of the two opposing surfaces of the ultrasonic medium and one slope forming an acute angle, and ultrasonic waves reflected thereby are reflected on the slope. A Q-switch control laser device characterized by the above. 【請求項３】請求項１に記載のレーザ装置において、超
音波媒体の斜面上にトランスデューサを設け、それによ
る超音波を対向２面により反射させるようにしたことを
特徴とするＱスィッチ制御レーザ装置。3. A laser device according to claim 1, wherein a transducer is provided on the slope of the ultrasonic medium, and the ultrasonic wave generated by the transducer is reflected by the two opposing surfaces. . 【請求項４】レーザ媒質を含むレーザ共振系内に配設し
た超音波Ｑスィッチを制御してパルスレーザ光を発生さ
せるレーザ装置であって、共振系を構成する１対のレー
ザ光反射手段の少なくとも一方にレーザ光の偏光面を回
転させる機能をもつ光学的手段を用い、この光学的手段
により偏光面が回転されたレーザ光がＱスィッチの超音
波媒体を通過するようにしたことを特徴とするＱスィッ
チ制御レーザ装置。4. A laser device for generating pulsed laser light by controlling an ultrasonic Q switch arranged in a laser resonance system including a laser medium, the laser device comprising a pair of laser light reflecting means constituting a resonance system. An optical means having a function of rotating the polarization plane of the laser light is used for at least one side, and the laser light whose polarization plane is rotated by this optical means is made to pass through the ultrasonic medium of the Q switch. Q switch control laser device. 【請求項５】請求項４に記載のレーザ装置において、偏
光面回転用の光学的手段がレーザ光に対して４分の１波
長の位相差を賦与するλ／４板であることを特徴とする
Ｑスィッチ制御レーザ装置。5. The laser device according to claim 4, wherein the optical means for rotating the plane of polarization is a λ / 4 plate which imparts a phase difference of ¼ wavelength to the laser light. Q switch control laser device. 【請求項６】請求項４に記載のレーザ装置において、偏
光面回転用の光学的手段がレーザ光を所定角度で全反射
させる平行な対向２面を備える斜方プリズムであること
を特徴とするＱスィッチ制御レーザ装置。6. A laser device according to claim 4, wherein the optical means for rotating the polarization plane is an orthorhombic prism having two parallel opposing surfaces for totally reflecting the laser light at a predetermined angle. Q switch control laser device. 【請求項７】請求項４に記載のレーザ装置において、Ｑ
スィッチ用の超音波媒質の側面をレーザ光に対する少な
くとも部分的な反射面に形成して、この側面を他方のレ
ーザ光反射手段として用いるようにしたことを特徴とす
るＱスィッチ制御レーザ装置。7. The laser device according to claim 4, wherein Q
A Q switch control laser device characterized in that a side surface of an ultrasonic medium for a switch is formed as at least a partial reflection surface for a laser beam, and the side surface is used as another laser beam reflecting means. 【請求項８】請求項４に記載のレーザ装置において、Ｑ
スィッチ用の超音波媒質に所定の面角で互いに交わる１
対の側面を設け、これら両側面でレーザ光を順次に全反
射させて偏光面を回転させるようにしたことを特徴とす
るＱスィッチ制御レーザ装置。8. The laser device according to claim 4, wherein Q
The ultrasonic medium for the switch intersects each other at a predetermined surface angle 1
A Q-switch control laser device characterized in that a pair of side surfaces are provided, and the polarization plane is rotated by sequentially totally reflecting the laser light on both side surfaces. 【請求項９】レーザ媒質を含むレーザ共振系内に配設し
た超音波Ｑスィッチを制御してパルスレーザ光を発生さ
せるレーザ装置であって、レーザ媒質としてスラブ状に
形成された光学結晶を用い、その細長い平行な対向２面
でレーザ光を繰り返し全反射させながらその偏光面を回
転させるようにしたことを特徴とするＱスィッチ制御レ
ーザ装置。9. A laser device for generating pulsed laser light by controlling an ultrasonic Q switch arranged in a laser resonance system including a laser medium, wherein an optical crystal formed in a slab shape is used as the laser medium. The Q-switch control laser device is characterized in that the plane of polarization is rotated while the laser light is repeatedly totally reflected by the two elongated parallel opposing surfaces. 【請求項１０】超音波Ｑスィッチの制御によりパルスレ
ーザ光を発生させるレーザ装置であって、超音波Ｑスィ
ッチの超音波媒体の超音波の進行方向に沿う表面をレー
ザ光に対する少なくとも部分的な反射面に形成し、これ
をレーザ媒質を含むレーザ共振系を構成する一方のレー
ザ光反射手段として用いるようにしたことを特徴とする
Ｑスィッチ制御レーザ装置。10. A laser device for generating pulsed laser light by controlling an ultrasonic Q switch, wherein at least partial reflection of the laser light is reflected on a surface of an ultrasonic medium of the ultrasonic Q switch along an ultrasonic wave traveling direction. A Q switch control laser device characterized in that it is formed on a surface and is used as one of the laser light reflecting means constituting a laser resonance system including a laser medium.