JPH0555671A - Semiconductor laser exciting solid-state laser - Google Patents
Semiconductor laser exciting solid-state laserInfo
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- JPH0555671A JPH0555671A JP21251391A JP21251391A JPH0555671A JP H0555671 A JPH0555671 A JP H0555671A JP 21251391 A JP21251391 A JP 21251391A JP 21251391 A JP21251391 A JP 21251391A JP H0555671 A JPH0555671 A JP H0555671A
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- solid
- laser
- semiconductor laser
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- state laser
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体レーザを励起光
源とする端面励起型固体レーザに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge-pumped solid-state laser using a semiconductor laser as a pumping light source.
【０００２】[0002]
【従来の技術】半導体レーザ励起固体レーザでは、固体
レーザを効率よく励起するために半導体レーザ光をレン
ズやビーム整形プリズムなどの結合光学系を通して励起
していた。しかし、最近では、レーザ装置の小型化のた
めに結合光学系を省略し、半導体レーザを固体レーザ結
晶に近接させて励起する方法が行われている。固体レー
ザ結晶であるＬｉＮｄＰ4 Ｏ12（ＬＮＰ）に励起用の半
導体レーザの放射面をほとんど密着させて励起する例と
しては「ＩＥＥＥ Ｐｈｏｔｏｎｉｃｓ Ｔｅｃｈｎｏ
ｌｏｇｙ Ｌｅｔｔｅｒｓ，Ｖｏｌ．１，Ｎｏ．５（１
９８９），ｐｐ．９７−９９」に記述がある。また、Ｎ
ｄ：ＹＶＯ4 結晶に半導体レーザを近接させて励起し、
固体レーザ共振器内に非線形光学結晶を挿入した内部共
振器型第２高調波発生によって波長５３２ｎｍのレーザ
出力を得た例として、「平成３年春季 第３８回応用物
理学関連連合講演会 講演予稿集、３１ｐ−Ｅ−１５」
に記述がある。2. Description of the Related Art In a semiconductor laser pumped solid-state laser, semiconductor laser light is pumped through a coupling optical system such as a lens and a beam shaping prism in order to efficiently pump the solid-state laser. However, recently, in order to miniaturize the laser device, a method of omitting the coupling optical system and causing the semiconductor laser to be close to the solid-state laser crystal for pumping has been performed. As an example in which the emission surface of a semiconductor laser for excitation is closely adhered to LiNdP 4 O 12 (LNP), which is a solid-state laser crystal, to perform excitation, “IEEE Photonics Technology” is used.
logy Letters, Vol. 1, No. 5 (1
989), pp. 97-99 ". Also, N
d: YVO 4 crystal is brought close to a semiconductor laser to be excited,
As an example of obtaining a laser output with a wavelength of 532 nm by generating an internal cavity type second harmonic by inserting a non-linear optical crystal into a solid-state laser cavity, "Spring 1991, 38th Joint Lecture on Applied Physics Lecture Presentation" Shu, 31p-E-15 "
There is a description in.
【０００３】[0003]
【発明が解決しようとする課題】半導体レーザを、固体
レーザ結晶に近接させて励起すると、固体レーザ結晶の
表面で反射が生じる。固体レーザ結晶の励起する側の面
は、半導体レーザの波長で低反射となる誘電体多層膜が
施してあるが、同時に固体レーザの発振波長で１００％
に近い反射率を持たせなければならないので、半導体レ
ーザの波長では数％以上の反射率を生じてしまう。従っ
て、半導体レーザから放射された励起光のうち固体レー
ザ結晶の表面で反射した光の一部は半導体レーザの活性
領域に結合して、半導体レーザ自身の発振に影響を与え
る。即ち、半導体レーザの放射側端面と固体レーザ結晶
の間で、半導体レーザの外部共振器を形成する。半導体
レーザは、通常、温度や注入電流で決まる最高利得の波
長の近傍で発振する。しかし、外部共振器が形成される
と、その外部共振器の縦モードが立つ波長のうち半導体
レーザの利得が最も高い波長においてのみ、半導体レー
ザは発振する。外部共振器長が熱膨張や機械的振動で変
化すると、半導体レーザの発振波長は変化することにな
る。外部共振器長の変化により、外部共振器の縦モード
が長波長側、あるいは短波長側にシフトしていくと、す
でに発振している縦モードの利得に比べ、１つだけ低波
長側、あるいは長波長側の縦モードの利得が大きくな
り、その瞬間にこの隣の縦モードで発振する。このこと
から発振波長の変動が、外部共振器の縦モード間隔と同
じ範囲で生じるといえる。固体レーザ結晶は吸収スペク
トルに波長依存性があるために、半導体レーザの発振波
長が変動すると、固体レーザにおける励起光の吸収量が
変動し、これに伴って固体レーザの出力も変動する。仮
に半導体レーザと固体レーザ結晶の間隔を５０μｍとす
ると、この外部共振器の縦モード間隔は約６．６ｎｍと
なるために、波長オーダーのわずかな外部共振器長の変
化で、約６．６ｎｍの範囲で発振波長が変化してしま
う。これだけ励起波長が変化すると固体レーザの出力変
動が著しく、Ｎｄ：ＹＡＧレーザなどの固体レーザでは
出力が最大値に対して２分の１以下に低下してしまう。
この効果は固体レーザ結晶と半導体レーザの間隔が狭く
なるほど著しい。また、この傾向は単一モードの半導体
レーザを用いた場合に特に顕著である。When a semiconductor laser is excited in the vicinity of a solid-state laser crystal and excited, reflection occurs on the surface of the solid-state laser crystal. The surface of the solid-state laser crystal on the pumping side is provided with a dielectric multilayer film that exhibits low reflection at the wavelength of the semiconductor laser, but at the same time, the oscillation wavelength of the solid-state laser is 100%.
Since the reflectance must be close to, the reflectance of several percent or more occurs at the wavelength of the semiconductor laser. Therefore, a part of the light reflected on the surface of the solid-state laser crystal among the excitation light emitted from the semiconductor laser is coupled to the active region of the semiconductor laser and affects the oscillation of the semiconductor laser itself. That is, an external resonator of the semiconductor laser is formed between the radiation side end face of the semiconductor laser and the solid-state laser crystal. A semiconductor laser usually oscillates in the vicinity of a wavelength of maximum gain determined by temperature and injection current. However, when the external resonator is formed, the semiconductor laser oscillates only at the wavelength where the gain of the semiconductor laser is the highest among the wavelengths in which the longitudinal mode of the external resonator stands. When the external cavity length changes due to thermal expansion or mechanical vibration, the oscillation wavelength of the semiconductor laser changes. When the longitudinal mode of the external resonator shifts to the long wavelength side or the short wavelength side due to the change of the external cavity length, only one lower wavelength side or the longitudinal mode gain that is already oscillating, or The gain of the longitudinal mode on the long wavelength side increases, and at that moment, oscillation occurs in the adjacent longitudinal mode. From this, it can be said that the fluctuation of the oscillation wavelength occurs within the same range as the longitudinal mode interval of the external resonator. Since the absorption spectrum of the solid-state laser crystal has wavelength dependence, if the oscillation wavelength of the semiconductor laser changes, the absorption amount of the excitation light in the solid-state laser also changes, and the output of the solid-state laser also changes accordingly. If the distance between the semiconductor laser and the solid-state laser crystal is 50 μm, the longitudinal mode distance of this external resonator is about 6.6 nm. Therefore, a slight change in the external resonator length on the order of wavelength results in about 6.6 nm. The oscillation wavelength changes within the range. If the excitation wavelength changes by this amount, the output fluctuation of the solid-state laser becomes remarkable, and the output of the solid-state laser such as the Nd: YAG laser is reduced to half or less of the maximum value.
This effect becomes more remarkable as the distance between the solid-state laser crystal and the semiconductor laser becomes narrower. Further, this tendency is particularly remarkable when a single mode semiconductor laser is used.
【０００４】本発明の目的は、固体レーザの出力変動を
小さくでき、出力の安定した半導体レーザ励起固体レー
ザを提供することにある。An object of the present invention is to provide a semiconductor laser pumped solid-state laser which can reduce the output fluctuation of the solid-state laser and has stable output.
【０００５】[0005]
【課題を解決するための手段】本発明は、半導体レーザ
の放射面を固体レーザ結晶に近接させて励起する半導体
レーザ励起固体レーザにおいて、前記固体レーザ結晶を
平行平板状とし、前記半導体レーザ側の前記固体レーザ
結晶の面に施した第１の誘電体多層膜の前記半導体レー
ザの波長における反射率をＲ1 とし、前記第１の誘電体
多層膜を設けた側とは反対側の前記固体レーザ結晶の面
に施した第２の誘電体多層膜の前記半導体レーザの波長
における反射率をＲ2 とし、前記半導体レーザと前記固
体レーザ結晶の間隔をｄとし、前記固体レーザ結晶の厚
さをｔとし、前記固体レーザ結晶の屈折率をｎとし、前
記固体レーザ結晶の前記半導体レーザの波長における吸
収係数をαとするとき、SUMMARY OF THE INVENTION The present invention is a semiconductor laser pumped solid-state laser in which a radiation surface of a semiconductor laser is excited in the vicinity of a solid-state laser crystal. The reflectance of the first dielectric multi-layered film applied to the surface of the solid-state laser crystal at the wavelength of the semiconductor laser is R 1, and the solid-state laser on the side opposite to the side where the first dielectric multi-layered film is provided. The reflectance of the second dielectric multilayer film applied to the crystal plane at the wavelength of the semiconductor laser is R 2 , the distance between the semiconductor laser and the solid-state laser crystal is d, and the thickness of the solid-state laser crystal is t. When the refractive index of the solid-state laser crystal is n and the absorption coefficient of the solid-state laser crystal at the wavelength of the semiconductor laser is α,
【０００６】[0006]
【数３】 [Equation 3]
【０００７】を満たすことを特徴とする。[0007] It is characterized by satisfying.
【０００８】また本発明は、半導体レーザの放射面を固
体レーザ結晶に近接させて励起する半導体レーザ励起固
体レーザにおいて、前記固体レーザ結晶を平凸状とし、
前記半導体レーザ側の前記固体レーザ結晶の平面に施し
た第１の誘電体多層膜の前記半導体レーザの波長におけ
る反射率をＲ1 とし、前記第１の誘電体多層膜を設けた
側とは反対側の前記固体レーザ結晶の凸球面に施した第
２の誘電体多層膜の前記半導体レーザの波長における反
射率をＲ2 とし、前記半導体レーザと前記固体レーザ結
晶の間隔をｄとし、前記固体レーザ結晶の厚さをｔと
し、前記固体レーザ結晶の屈折率をｎとし、前記固体レ
ーザ結晶の前記半導体レーザの波長における吸収係数を
αとし、前記凸球面の曲率半径がｒであるとき、The present invention also provides a semiconductor laser pumped solid-state laser in which a radiation surface of the semiconductor laser is brought close to a solid-state laser crystal to pump the solid-state laser crystal, and the solid-state laser crystal is plano-convex.
The reflectance of the first dielectric multilayer film formed on the plane of the solid-state laser crystal on the semiconductor laser side at the wavelength of the semiconductor laser is R 1 and is opposite to the side on which the first dielectric multilayer film is provided. The reflectance of the second dielectric multilayer film formed on the convex spherical surface of the solid-state laser crystal on the side at the wavelength of the semiconductor laser is R 2 , the distance between the semiconductor laser and the solid-state laser crystal is d, and the solid-state laser is When the crystal thickness is t, the refractive index of the solid-state laser crystal is n, the absorption coefficient of the solid-state laser crystal at the wavelength of the semiconductor laser is α, and the radius of curvature of the convex spherical surface is r,
【０００９】[0009]
【数４】 [Equation 4]
【００１０】となることを特徴とする。It is characterized in that
【００１１】[0011]
【作用】半導体レーザの発振波長が、外部共振器の縦モ
ードに支配されるならば、外部共振器長を長くすること
によって、外部共振器の縦モード間隔を小さくすること
ができる。この、縦モード間隔が小さくなると波長変動
幅が小さくなり、固体レーザの出力変動も小さくなる。
しかし、半導体レーザと固体レーザ結晶の間隔を大きく
することは、結合光学系を省略し半導体レーザを近接さ
せて励起する方法において、励起効率の低下をまねく。
そこで本発明では固体レーザ結晶の励起光が入射する側
の面の励起光に対する反射率を小さくし、もう一方の面
を励起光に対して高反射となるようにそれぞれ誘電体多
層膜を施すことにより問題を解決する手法を見い出し
た。前者を第１の誘電体多層膜、後者を第２の誘電体多
層膜と呼ぶことにする。このような反射率をもつ誘電体
多層膜を施すと、半導体レーザの動作に影響を与える反
射光の量のうち、第２の誘電体多層膜からの方を多くす
ることができる。このとき半導体レーザの放射側の面と
第１の誘電体多層膜との間で形成される外部共振器によ
る効果よりも、半導体レーザの放射側の面と第２の誘電
体多層膜との間で形成される外部共振器の効果の方が半
導体レーザの動作に支配的になる。当然、後者の外部共
振器の方が、固体レーザの厚さの分だけ外部共振器が長
くなるので、その縦モード間隔が狭くなるために、固体
レーザの出力変動幅も小さくなる。If the oscillation wavelength of the semiconductor laser is governed by the longitudinal mode of the external cavity, the longitudinal mode interval of the external cavity can be reduced by increasing the length of the external cavity. As the longitudinal mode interval becomes smaller, the wavelength fluctuation width becomes smaller and the output fluctuation of the solid-state laser also becomes smaller.
However, increasing the distance between the semiconductor laser and the solid-state laser crystal leads to a reduction in pumping efficiency in a method in which the coupling optical system is omitted and the semiconductor laser is pumped in close proximity.
Therefore, in the present invention, the reflectance of the surface of the solid-state laser crystal on the side where the excitation light is incident to the excitation light is reduced, and the other surface is provided with the respective dielectric multilayer films so as to be highly reflective to the excitation light. I found a method to solve the problem. The former will be referred to as a first dielectric multilayer film and the latter will be referred to as a second dielectric multilayer film. When the dielectric multilayer film having such a reflectance is applied, the amount of reflected light that affects the operation of the semiconductor laser can be increased from the second dielectric multilayer film. At this time, the effect of the external resonator formed between the radiation side surface of the semiconductor laser and the first dielectric multilayer film is larger than that between the radiation side surface of the semiconductor laser and the second dielectric multilayer film. The effect of the external resonator formed in 1) becomes dominant in the operation of the semiconductor laser. As a matter of course, in the latter external resonator, the external resonator becomes longer by the thickness of the solid-state laser, and the longitudinal mode interval becomes narrower, so that the output fluctuation width of the solid-state laser also becomes smaller.
【００１２】半導体レーザの放射面と第１の誘電体多層
膜までの距離をｄ、第１の誘電体多層膜と第２の誘電体
多層膜の間隔、すなわち固体レーザ結晶の厚さをｔ、固
体レーザ結晶の屈折率をｎとする。半導体レーザと第２
の誘電体多層膜の間で形成される外部共振器の縦モード
間隔ΔλはThe distance between the emitting surface of the semiconductor laser and the first dielectric multilayer film is d, the distance between the first dielectric multilayer film and the second dielectric multilayer film, that is, the thickness of the solid laser crystal is t, The refractive index of the solid-state laser crystal is n. Semiconductor laser and second
The longitudinal mode interval Δλ of the external resonator formed between the dielectric multilayer films of
【００１３】[0013]
【数５】 [Equation 5]
【００１４】となる。ここでλは半導体レーザの波長で
ある。仮に、λ＝０．８１μｍ，ｄ＝５０μｍ，ｔ＝
１．０ｍｍ，ｎ＝２．０とすると、Δλ＝０．１６ｎｍ
となる。一般的に、固体レーザ結晶の吸収帯域幅が数ｎ
ｍであることを考慮すると、この程度の波長変動であれ
ば、励起光の固体レーザ結晶における吸収量の変化は無
視しうる程度に小さいので、固体レーザ出力は安定す
る。[0014] Where λ is the wavelength of the semiconductor laser. If λ = 0.81 μm, d = 50 μm, t =
Assuming 1.0 mm and n = 2.0, Δλ = 0.16 nm
Becomes Generally, the absorption bandwidth of a solid-state laser crystal is several n
Considering that m, the change in the absorption amount of the pumping light in the solid-state laser crystal is so small as to be negligible with such a wavelength fluctuation, so that the solid-state laser output is stable.
【００１５】第１の誘電体多層膜による反射光の影響よ
りも、第２の誘電体多層膜による反射光の影響が大きく
なるための条件は、The condition for the influence of the reflected light from the second dielectric multilayer film to be larger than the influence of the reflected light from the first dielectric multilayer film is as follows.
【００１６】[0016]
【数６】 [Equation 6]
【００１７】となる。ここで、αは固体レーザ結晶の吸
収係数、Ｒ1 ，Ｒ2 はそれぞれ第１の誘電体多層膜及び
第２の誘電体多層膜の半導体レーザの波長における反射
率である。この式は、第１及び第２の誘電体多層膜から
の反射光の半導体レーザの放射面における電力密度のう
ち、第２の誘電体多層膜からの方が強くなる条件を表し
たものである。右辺の、ｅｘｐ（−２αｔ）は固体レー
ザ結晶の往復伝搬による光強度の減少を表し、（１−Ｒ
1 ）2 は第１の誘電体多層膜を２度透過することによる
光強度の減少を表し、また｛ｄ／（ｄ＋ｔ／ｎ）｝2 は
放射による電力密度の減少を表している。[0017] Here, α is the absorption coefficient of the solid-state laser crystal, and R 1 and R 2 are the reflectances of the first dielectric multilayer film and the second dielectric multilayer film at the wavelength of the semiconductor laser, respectively. This equation represents a condition that the reflected light from the first and second dielectric multilayer films has a higher power density at the emission surface of the semiconductor laser from the second dielectric multilayer film. .. Exp (-2αt) on the right side represents the decrease in the light intensity due to the round-trip propagation of the solid-state laser crystal, (1-R
1 ) 2 represents the reduction of the light intensity by transmitting the first dielectric multilayer film twice, and {d / (d + t / n)} 2 represents the reduction of the power density due to radiation.
【００１８】第２の誘電体多層膜を施す側の固体レーザ
結晶の面を平面から凸球面にすることにより、この面に
よる半導体レーザ光の反射光が半導体レーザの発光位置
に戻ったときの電力密度をより高くできる。そのため半
導体レーザの放射面と第２の誘電体多層膜の間に形成さ
れる外部共振器の効果が一層顕著となる。また、第１及
び第２の誘電体多層膜の反射率Ｒ1 ，Ｒ2 などのパラメ
ータの許容値を広くすることができる。凸球面の曲率半
径をｒとすると、第１の誘電体多層膜による反射光の電
力密度よりも、第２の誘電体多層膜による反射光の電力
密度が大きくなるための条件は、By making the surface of the solid-state laser crystal on the side on which the second dielectric multilayer film is applied from a flat surface to a convex spherical surface, the power when the reflected light of the semiconductor laser light by this surface returns to the emission position of the semiconductor laser. Higher density can be achieved. Therefore, the effect of the external resonator formed between the emission surface of the semiconductor laser and the second dielectric multilayer film becomes more remarkable. Further, it is possible to widen the permissible values of the parameters such as the reflectances R 1 and R 2 of the first and second dielectric multilayer films. When the radius of curvature of the convex spherical surface is r, the condition for the power density of the reflected light by the second dielectric multilayer film to be larger than the power density of the reflected light by the first dielectric multilayer film is
【００１９】[0019]
【数７】 [Equation 7]
【００２０】となる。数６と異なるのは、右辺の［ｄ／
（ｄ＋ｔ／ｎ）／｛１−（ｔ＋ｎｄ）／ｒ｝］2 で、こ
れは固体レーザ結晶の第２の誘電体多層膜を施す側の面
を曲率半径ｒの凸球面とした影響を含んだ、放射による
電力密度の低下を表している。[0020] The difference from Equation 6 is that [d /
(D + t / n) / {1- (t + nd) / r}] 2 , which includes the effect that the surface of the solid-state laser crystal on which the second dielectric multilayer film is applied is a convex spherical surface with a radius of curvature r. , Represents the reduction in power density due to radiation.
【００２１】[0021]
【実施例】以下、図面を参照しながら本発明の実施例に
ついて説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００２２】本発明の第１の実施例の構成図を図１に示
す。固体レーザ結晶には厚さが０．３ｍｍの平行平板状
のＮｄ：ＹＶＯ4 結晶２を用いている。Ｎｄ：ＹＶＯ4
結晶２の片側端面には励起波長に対して反射率が２％と
なる第１の誘電体多層膜３が施してある。また、Ｎｄ：
ＹＶＯ4 結晶２の第１の誘電体多層膜３が施してある面
に向かい合う面には、励起波長に対して反射が９５％と
なる第２の誘電体多層膜４が設けてある。Ｎｄ：ＹＶＯ
4 を波長１０６４ｎｍで発振させるために、この波長に
おける反射率は第１の誘電体多層膜３ではほぼ１００％
に、第２の誘電体多層膜４は１％以下にしてある。Ｎ
ｄ：ＹＶＯ4 結晶２の第１の誘電体多層膜３を設けてあ
る側には励起のための波長が約０．８１μｍの半導体レ
ーザ１を、Ｎｄ：ＹＶＯ4 ２にその放射面を１００μｍ
まで近接させて設けてある。Ｎｄ：ＹＶＯ4 結晶２の第
２の誘電体多層膜４を設けた側には、固体レーザの出力
を取り出す出力ミラー５が設けてある。半導体レーザの
波長においてＮｄ：ＹＶＯ4 結晶２の屈折率が約２．
１、吸収係数が約３ｍｍ-1である。第１の実施例では、
数６の右辺は、左辺に対して１．２９倍になるために数
６が十分なり立ち、波長変動幅も０．４４ｎｍ程度と小
さくなるので、本発明の効果が十分発揮される。本発明
を使用しなければ出力が最大値に対して２分の１以下ま
で変動するが、本発明によれば、出力変動は１０％以内
に抑えることができる。A block diagram of the first embodiment of the present invention is shown in FIG. As the solid-state laser crystal, a parallel plate-shaped Nd: YVO 4 crystal 2 having a thickness of 0.3 mm is used. Nd: YVO 4
A first dielectric multilayer film 3 having a reflectance of 2% with respect to the excitation wavelength is formed on one end face of the crystal 2. Also, Nd:
On the surface of the YVO 4 crystal 2 facing the surface provided with the first dielectric multilayer film 3, a second dielectric multilayer film 4 having a reflection of 95% with respect to the excitation wavelength is provided. Nd: YVO
In order to oscillate 4 at a wavelength of 1064 nm, the reflectance at this wavelength is almost 100% in the first dielectric multilayer film 3.
In addition, the second dielectric multilayer film 4 is 1% or less. N
On the side of the d: YVO 4 crystal 2 where the first dielectric multilayer film 3 is provided, a semiconductor laser 1 having a wavelength of about 0.81 μm for excitation is provided, and for Nd: YVO 4 2, the emission surface thereof is 100 μm.
It is provided close to. An output mirror 5 for extracting the output of the solid-state laser is provided on the side of the Nd: YVO 4 crystal 2 on which the second dielectric multilayer film 4 is provided. At the wavelength of the semiconductor laser, the refractive index of the Nd: YVO 4 crystal 2 is about 2.
1, the absorption coefficient is about 3 mm -1 . In the first embodiment,
Since the right side of the equation 6 is 1.29 times as large as the left side, the equation 6 is sufficient, and the wavelength fluctuation width is as small as about 0.44 nm, so that the effect of the present invention is sufficiently exerted. If the present invention is not used, the output fluctuates up to ½ or less of the maximum value, but according to the present invention, the output fluctuation can be suppressed within 10%.
【００２３】本発明の第２の実施例の構成図を図２に示
す。第２の実施例を構成する要素は第１の実施例と同じ
であるが、異なる点は、Ｎｄ：ＹＶＯ4 結晶２の第２の
誘電体多層膜４を設けた側の面が曲率半径１０ｍｍの凸
球面状にしてあることである。Ｎｄ：ＹＶＯ4 結晶２の
厚さは０．３ｍｍである。また、半導体レーザ１とＮ
ｄ：ＹＶＯ4 結晶２の間隔は１００μｍである。第２の
実施例では、数７の右辺は左辺に対して１．４２倍とな
るので、本発明の効果が一層高められる。A block diagram of the second embodiment of the present invention is shown in FIG. The constituent elements of the second embodiment are the same as those of the first embodiment, except that the surface of the Nd: YVO 4 crystal 2 on which the second dielectric multilayer film 4 is provided has a radius of curvature of 10 mm. That is, it has a convex spherical shape. The thickness of the Nd: YVO 4 crystal 2 is 0.3 mm. In addition, the semiconductor lasers 1 and N
The distance between the d: YVO 4 crystals 2 is 100 μm. In the second embodiment, the right side of Expression 7 is 1.42 times as large as the left side, so that the effect of the present invention is further enhanced.
【００２４】本発明の第１及び第２の実施例では固体レ
ーザ結晶の材料としてＮｄ：ＹＶＯ4 を用いたが、Ｎ
ｄ：ＹＡＧ、Ｎｄ：ＹＬＦやＬＮＰなど、半導体レーザ
を励起光源とすることが可能な固体レーザ結晶であれば
本発明が有効なことは言うまでもない。In the first and second embodiments of the present invention, Nd: YVO 4 is used as the material for the solid-state laser crystal, but N
Needless to say, the present invention is effective as long as it is a solid-state laser crystal such as d: YAG, Nd: YLF, or LNP that can use a semiconductor laser as an excitation light source.
【００２５】また、本発明では出力ミラーを独立に設け
てあるが、第２の誘電体多層膜４を励起波長及び固体レ
ーザの発振波長に対して高反射となるものとすることに
より、固体レーザ結晶の片端面を出力ミラーとして兼ね
ることもできる。Further, although the output mirror is provided independently in the present invention, by providing the second dielectric multilayer film 4 with high reflection with respect to the pumping wavelength and the oscillation wavelength of the solid-state laser, the solid-state laser can be obtained. One end face of the crystal can also serve as the output mirror.
【００２６】[0026]
【発明の効果】以上詳述したように、本発明によれば、
固体レーザを励起する半導体レーザの波長変動幅を小さ
くすることができるために、固体レーザの出力変動を小
さくでき、出力の安定した小型固体レーザを提供でき
る。As described in detail above, according to the present invention,
Since the wavelength fluctuation width of the semiconductor laser that excites the solid-state laser can be reduced, the output fluctuation of the solid-state laser can be reduced, and a small solid-state laser with stable output can be provided.
【図１】本発明の第１の実施例を説明するための図であ
る。FIG. 1 is a diagram for explaining a first embodiment of the present invention.
【図２】本発明の第２の実施例を説明するための図であ
る。FIG. 2 is a diagram for explaining a second embodiment of the present invention.
１ 半導体レーザ ２ Ｎｄ：ＹＶＯ4 結晶 ３ 第１の誘電体多層膜 ４ 第２の誘電体多層膜 ５ 出力ミラー1 Semiconductor Laser 2 Nd: YVO 4 Crystal 3 First Dielectric Multilayer Film 4 Second Dielectric Multilayer Film 5 Output Mirror
Claims (2)
近接させて励起する半導体レーザ励起固体レーザにおい
て、前記固体レーザ結晶を平行平板状とし、前記半導体
レーザ側の前記固体レーザ結晶の面に施した第１の誘電
体多層膜の前記半導体レーザの波長における反射率をＲ
1 とし、前記第１の誘電体多層膜を設けた側とは反対側
の前記固体レーザ結晶の面に施した第２の誘電体多層膜
の前記半導体レーザの波長における反射率をＲ2 とし、
前記半導体レーザと前記固体レーザ結晶の間隔をｄと
し、前記固体レーザ結晶の厚さをｔとし、前記固体レー
ザ結晶の屈折率をｎとし、前記固体レーザ結晶の前記半
導体レーザの波長における吸収係数をαとするとき、 【数１】 を満たすことを特徴とする半導体レーザ励起固体レー
ザ。1. A semiconductor-laser-pumped solid-state laser for exciting a solid-state laser crystal in which a radiation surface of the semiconductor laser is close to the solid-state laser crystal. The reflectance of the first dielectric multilayer film at the wavelength of the semiconductor laser is R
1 , the reflectance of the second dielectric multilayer film on the surface of the solid-state laser crystal opposite to the side on which the first dielectric multilayer film is provided is R 2 at the wavelength of the semiconductor laser,
The distance between the semiconductor laser and the solid laser crystal is d, the thickness of the solid laser crystal is t, the refractive index of the solid laser crystal is n, and the absorption coefficient of the solid laser crystal at the wavelength of the semiconductor laser is Let α be the following: A semiconductor laser pumped solid-state laser characterized by satisfying:
近接させて励起する半導体レーザ励起固体レーザにおい
て、前記固体レーザ結晶を平凸状とし、前記半導体レー
ザ側の前記固体レーザ結晶の平面に施した第１の誘電体
多層膜の前記半導体レーザの波長における反射率をＲ1
とし、前記第１の誘電体多層膜を設けた側とは反対側の
前記固体レーザ結晶の凸球面に施した第２の誘電体多層
膜の前記半導体レーザの波長における反射率をＲ2 と
し、前記半導体レーザと前記固体レーザ結晶の間隔をｄ
とし、前記固体レーザ結晶の厚さをｔとし、前記固体レ
ーザ結晶の屈折率をｎとし、前記固体レーザ結晶の前記
半導体レーザの波長における吸収係数をαとし、前記凸
球面の曲率半径がｒであるとき、 【数２】 となることを特徴とする半導体レーザ励起固体レーザ。2. A semiconductor-laser-pumped solid-state laser for exciting a semiconductor laser so that its emission surface is close to the solid-state laser crystal. The reflectance of the first dielectric multilayer film at the wavelength of the semiconductor laser is R 1
And R 2 is the reflectance at the wavelength of the semiconductor laser of the second dielectric multilayer film formed on the convex spherical surface of the solid-state laser crystal on the side opposite to the side on which the first dielectric multilayer film is provided, The distance between the semiconductor laser and the solid-state laser crystal is d
Where t is the thickness of the solid-state laser crystal, n is the refractive index of the solid-state laser crystal, α is the absorption coefficient of the solid-state laser crystal at the wavelength of the semiconductor laser, and r is the radius of curvature of the convex spherical surface. When there is, A semiconductor laser pumped solid-state laser characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21251391A JP2757608B2 (en) | 1991-08-26 | 1991-08-26 | Semiconductor laser pumped solid state laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21251391A JP2757608B2 (en) | 1991-08-26 | 1991-08-26 | Semiconductor laser pumped solid state laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0555671A true JPH0555671A (en) | 1993-03-05 |
| JP2757608B2 JP2757608B2 (en) | 1998-05-25 |
Family
ID=16623920
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21251391A Expired - Lifetime JP2757608B2 (en) | 1991-08-26 | 1991-08-26 | Semiconductor laser pumped solid state laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2757608B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006344863A (en) * | 2005-06-10 | 2006-12-21 | Fujifilm Holdings Corp | Mode-locked laser device |
| JP2007173394A (en) * | 2005-12-20 | 2007-07-05 | Denso Corp | Multiple wavelength laser equipment |
| JP2013120799A (en) * | 2011-12-06 | 2013-06-17 | Mitsubishi Electric Corp | Laser device |
-
1991
- 1991-08-26 JP JP21251391A patent/JP2757608B2/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006344863A (en) * | 2005-06-10 | 2006-12-21 | Fujifilm Holdings Corp | Mode-locked laser device |
| JP4579062B2 (en) * | 2005-06-10 | 2010-11-10 | 富士フイルム株式会社 | Mode-locked laser device |
| JP2007173394A (en) * | 2005-12-20 | 2007-07-05 | Denso Corp | Multiple wavelength laser equipment |
| US7564890B2 (en) | 2005-12-20 | 2009-07-21 | Denso Corporation | Laser equipment |
| JP4518018B2 (en) * | 2005-12-20 | 2010-08-04 | 株式会社デンソー | Multi-wavelength laser equipment |
| US7843987B2 (en) | 2005-12-20 | 2010-11-30 | Denso Corporation | Laser equipment |
| JP2013120799A (en) * | 2011-12-06 | 2013-06-17 | Mitsubishi Electric Corp | Laser device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2757608B2 (en) | 1998-05-25 |
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