JPS6364914B2 - - Google Patents
Info
- Publication number
- JPS6364914B2 JPS6364914B2 JP57103215A JP10321582A JPS6364914B2 JP S6364914 B2 JPS6364914 B2 JP S6364914B2 JP 57103215 A JP57103215 A JP 57103215A JP 10321582 A JP10321582 A JP 10321582A JP S6364914 B2 JPS6364914 B2 JP S6364914B2
- Authority
- JP
- Japan
- Prior art keywords
- refractive index
- oscillation frequency
- laser
- total reflection
- reflection mirror
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000010355 oscillation Effects 0.000 claims description 17
- 230000008878 coupling Effects 0.000 description 6
- 238000010168 coupling process Methods 0.000 description 6
- 238000005859 coupling reaction Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
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
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
Description
【発明の詳細な説明】
本発明はレーザー発振周波数制御装置に関する
ものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser oscillation frequency control device.
精密な科学計測等には周波数の安定したレーザ
ーが必要であるが、一般にレーザー発振器はレー
ザー自体の発する熱などのため、共振器長が絶え
ず変動する。このため、レーザー発振周波数が変
動してしまう。 Precise scientific measurements require lasers with stable frequencies, but generally the resonator length of laser oscillators constantly fluctuates due to the heat generated by the laser itself. As a result, the laser oscillation frequency fluctuates.
この周波数変動を抑えるためには、周波数変動
を検出して誤差信号に変換し、この信号によつて
共振器の周波数を制御することが必要である。 In order to suppress this frequency fluctuation, it is necessary to detect the frequency fluctuation, convert it into an error signal, and use this signal to control the frequency of the resonator.
第１図に示すようにレーザー発振器はレーザ媒
質１と、その両側の全反射鏡２と出力結合鏡３と
によつて構成される。従来、レーザーの発振周波
数を制御するには、全反射鏡２を前後に移動する
ことが行なわれている。全反射鏡２を圧電素子４
によつて保持し、圧電素子４にかける電気信号発
生器５からの電気信号によつて全反射鏡２と出力
結合鏡３との間隔、すなわち共振器長を制御する
ことができる。全反射鏡２の位置調整は、圧電素
子４のかわりに機械的に行なうこともある。これ
らの方法はいずれも全反射鏡２の駆動装置を必要
とし、比較的複雑な機構となつてしまう。また、
全反射鏡２を大きく移動させると、全反射鏡２の
傾き角にずれを生じてしまう欠点がある。 As shown in FIG. 1, the laser oscillator is composed of a laser medium 1, a total reflection mirror 2 on both sides thereof, and an output coupling mirror 3. Conventionally, in order to control the oscillation frequency of a laser, the total reflection mirror 2 is moved back and forth. Total reflection mirror 2 is replaced by piezoelectric element 4
The distance between the total reflection mirror 2 and the output coupling mirror 3, that is, the resonator length, can be controlled by an electric signal from an electric signal generator 5 applied to the piezoelectric element 4. The position adjustment of the total reflection mirror 2 may be performed mechanically instead of using the piezoelectric element 4. All of these methods require a driving device for the total reflection mirror 2, resulting in a relatively complicated mechanism. Also,
If the total reflection mirror 2 is moved largely, there is a drawback that the inclination angle of the total reflection mirror 2 is shifted.
本発明は、全反射鏡の位置調整機構を用いるこ
となく、レーザー発振周波数を調整することを目
的とする。 An object of the present invention is to adjust the laser oscillation frequency without using a total reflection mirror position adjustment mechanism.
本発明は、共振器内に屈折率の制御可能な装置
を設け、その屈折率を変化させることによつて発
振周波数を制御するようにしたものである。 In the present invention, a refractive index controllable device is provided in a resonator, and the oscillation frequency is controlled by changing the refractive index.
第２図は本発明のレーザー発振周波数制御装置
の原理図を示す。１はレーザー媒質、２は全反射
鏡、３は出力結合鏡であり、レーザ媒質１と出力
結合鏡３との間（必らずしもこの位置にある必要
はなく、共振器内であれば良い）に屈折率変化装
置６が設けられており、この屈折率変化装置６は
屈折率調整装置７によつて制御される。 FIG. 2 shows a principle diagram of the laser oscillation frequency control device of the present invention. 1 is a laser medium, 2 is a total reflection mirror, and 3 is an output coupling mirror, which is located between the laser medium 1 and the output coupling mirror 3 (it does not necessarily have to be in this position, but as long as it is inside the resonator) A refractive index changing device 6 is provided in the refractive index changing device 6, which is controlled by a refractive index adjusting device 7.
共振器長ｌ、屈折率nOの共振器は以下の共振条
件を満たす周波数νで発振する。 A resonator with a resonator length l and a refractive index n O oscillates at a frequency ν that satisfies the following resonance conditions.
2nOｌ＝NC／ν (1) ここでＣは光速Ｎは正の整数である。 2n O l=NC/ν (1) Here, C is the speed of light N is a positive integer.
第２図に示すように光軸方向の長さｄの屈折率
変化装置６が共振器内にある場合、この屈折率を
n1とすると共振条件１は
２｛nO（ｌ―ｄ）＋n1d｝＝NC／ν1 (2)
である。従つて屈折率変化装置６の屈折率n1を屈
折率調整装置７によつて制御してやれば、発振周
波数ν1を制御することができる。この方法を用い
れば、全反射鏡２の位置を前後させる機構なし
で、発振周波数を制御することができる。 As shown in FIG. 2, when a refractive index changing device 6 with a length d in the optical axis direction is located in the resonator, this refractive index is
When n 1 , resonance condition 1 is 2{n O (ld)+n 1 d}=NC/ν 1 (2). Therefore, if the refractive index n 1 of the refractive index changing device 6 is controlled by the refractive index adjusting device 7, the oscillation frequency ν 1 can be controlled. Using this method, the oscillation frequency can be controlled without a mechanism for moving the total reflection mirror 2 back and forth.
第３図に本発明にレーザー発振周波数制御装置
の実施例の構成を示す。 FIG. 3 shows the configuration of an embodiment of the laser oscillation frequency control device according to the present invention.
全反射鏡２と出力結合鏡３とで共振器を構成
し、共振器内に設けられたレーザ媒質１と屈折率
変化装置としての気体セル６１とは窓８によつて
仕切られている。 The total reflection mirror 2 and the output coupling mirror 3 constitute a resonator, and the laser medium 1 provided in the resonator and the gas cell 61 as a refractive index changing device are separated by a window 8.
気体セル中に陽極７２、陰極７３の１対の電極
を設け、電源７４によつて電極間にグロー放電を
行わせ、放電電流を制御することによつて屈折率
を変化させるものである。 A pair of electrodes, an anode 72 and a cathode 73, are provided in the gas cell, a glow discharge is caused between the electrodes by a power source 74, and the refractive index is changed by controlling the discharge current.
放電時における気体の屈折率n1は
n1＝１−１／２ Ne e2／mε0ω2
＋2πanNn＋2π
〓i
aiNi (3)
で与えられる。ここでNeは電子密度、ｅは電子
の電荷、ｍは電子の質量、εOは誘電率、ωは光の
振動数、αmは中性原子の分極率、Nmは中性原
子の密度、αiはイオンの分極率、Niはイオンの
密度である。第２項は電子による項、第３項は中
性原子による項、第４項はイオンによる項であ
る。放電電流を変えれば、電子密度Ne、中性原
子密度Nm、イオン密度Niが変わるので、気体の
屈折率n1が変わるので、これにより発振周波数を
変えることができる。 The refractive index n 1 of the gas during discharge is given by n 1 =1-1/2 Ne e 2 /mε 0 ω 2 +2πa n N n +2π 〓 i a i N i (3). Here, Ne is the electron density, e is the electron charge, m is the electron mass, ε O is the dielectric constant, ω is the frequency of light, αm is the polarizability of the neutral atom, Nm is the density of the neutral atom, αi is the ion polarizability and Ni is the ion density. The second term is a term due to electrons, the third term is a term due to neutral atoms, and the fourth term is a term due to ions. By changing the discharge current, the electron density Ne, neutral atom density Nm, and ion density Ni change, which changes the refractive index n 1 of the gas, thereby changing the oscillation frequency.
本実施例においては、気体セル内には、全圧
25torr、混合比CO2：N2：He＝１：３：15の混
合ガスを入れ、電極間隔60cmのき、放電電流
50mAに対して発振周波数を1.2MHzシフトさせる
ことができた。 In this example, the total pressure inside the gas cell is
25 torr, mixed gas with a mixing ratio of CO 2 :N 2 :He=1:3:15, electrode spacing 60 cm, discharge current.
We were able to shift the oscillation frequency by 1.2MHz for 50mA.
以上説明したように本発明によれば共振器内に
気体セルを設け、気体セルの屈折率を変化させる
ことによつてレーザーの発振周波数を全反射鏡の
移動なしで制御することができる。 As explained above, according to the present invention, by providing a gas cell in a resonator and changing the refractive index of the gas cell, the oscillation frequency of the laser can be controlled without moving the total reflection mirror.
第１図は圧電素子を使用した従来のレーザー発
振器の発振周波数制御装置の概略構成図、第２図
は本発明のレーザー発振周波数制御装置の原理説
明図、第３図は本発明の実施例であるレーザー発
振周波数制御装置の概略構成図である。
１……レーザ媒質、２……全反射鏡、３……出
力結合鏡、４……圧電素子、５……電気信号発生
器、６……屈折率変化装置、７……屈折率調整装
置、６１……気体セル、７２……陽極、７３……
陰極、７４……電源。
Fig. 1 is a schematic configuration diagram of a conventional oscillation frequency control device for a laser oscillator using a piezoelectric element, Fig. 2 is an explanatory diagram of the principle of the laser oscillation frequency control device of the present invention, and Fig. 3 is an embodiment of the present invention. 1 is a schematic configuration diagram of a certain laser oscillation frequency control device. DESCRIPTION OF SYMBOLS 1... Laser medium, 2... Total reflection mirror, 3... Output coupling mirror, 4... Piezoelectric element, 5... Electric signal generator, 6... Refractive index changing device, 7... Refractive index adjusting device, 61... Gas cell, 72... Anode, 73...
Cathode, 74...power supply.
Claims (1)
前記気体セル中に１対の電極を設け、前記電極間
でグロー放電を行う構成を有し、前記電極間の放
電電流を制御することにより屈折率を変化させ、
発振周波数を制御することを特徴とするレーザー
発振周波数制御装置。1 Has a laser medium and a gas cell in the resonator,
A pair of electrodes is provided in the gas cell, and the gas cell has a configuration in which glow discharge is performed between the electrodes, and the refractive index is changed by controlling the discharge current between the electrodes,
A laser oscillation frequency control device characterized by controlling an oscillation frequency.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10321582A JPS58219786A (en) | 1982-06-15 | 1982-06-15 | Device for controlling oscillating frequency of laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10321582A JPS58219786A (en) | 1982-06-15 | 1982-06-15 | Device for controlling oscillating frequency of laser |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58219786A JPS58219786A (en) | 1983-12-21 |
| JPS6364914B2 true JPS6364914B2 (en) | 1988-12-14 |
Family
ID=14348275
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10321582A Granted JPS58219786A (en) | 1982-06-15 | 1982-06-15 | Device for controlling oscillating frequency of laser |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58219786A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111596529B (en) * | 2020-05-29 | 2023-12-29 | 成都天马微电子有限公司 | Exposure apparatus and method of using the same |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55138287A (en) * | 1979-04-11 | 1980-10-28 | Nec Corp | Linear-polarization type gas laser tube |
-
1982
- 1982-06-15 JP JP10321582A patent/JPS58219786A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55138287A (en) * | 1979-04-11 | 1980-10-28 | Nec Corp | Linear-polarization type gas laser tube |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58219786A (en) | 1983-12-21 |
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