JPS63227079A - Highly repetitive pulse laser oscillator - Google Patents

Abstract

PURPOSE:To obtain high-output laser light enabling spatially uniform preionization having high electron density by disposing a fast pulse power supply as a generating power supply for preionization and setting quiescent among each pulse of a pulse train output from the fast pulse power supply. CONSTITUTION:A fast pulse power supply 11 is arranged as a power supply generating preionization conducted prior to main discharge, and quiescent time is set among each pulse of a pulse train output from the fast pulse power supply 11. The fast pulse power supply 11 is connected to pulse preionization electrodes 3a, 3b mounted to a first main electrode 1 and a second main electrode 2, or connected between the oppositely disposed first main electrode 1 and second main electrode 2. Electron density can be equalized during the quiescent time set among pulses from the pulse power supply 11, and electrons can be generated by a plurality of pulses, thus largely increasing electron density. Accordingly, high-output laser light enabling spatially uniform preionization having high electron density can be acquired.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high repetition pulse laser oscillation device.

(Prior Art) Generally, in order to obtain laser oscillation, it is necessary to generate a spatially uniform discharge in the laser medium, but TEACO2
In high-repetition pulse laser generators that generate short-pulse laser beams such as lasers and excimer lasers, the operating pressure is as high as the diffuse pressure, so the above discharge converges.
Easy to arc. To prevent this, it is common to adjust the electric field distribution in the main discharge space or to perform preliminary ionization prior to the main discharge.

FIG. 4 shows an example of a conventional high repetition pulse laser oscillation device. That is, a second main electrode 2 is disposed at a position facing the first main electrode 1 disposed in the laser medium, and a plurality of pre-ionized electrodes are provided on both sides of the first main electrode 1 in the longitudinal direction. Electrodes 3a are arranged at appropriate intervals via a peaking capacitor 4a, and the second main electrode 2 also has a plurality of pre-ionization electrodes 3 on both sides in the longitudinal direction.
b is disposed at a position facing the pre-ionization electrode 3a via the peaking capacitor 4b.

Further, the two main electrodes 1 and 2 arranged opposite to each other are connected to a main pulse power source 5.

Roughly speaking, optical resonators 6 are disposed at both longitudinal ends of the two opposing main electrodes 1 and 2, and a laser beam 7 is output.

In the conventional high-repetition pulse laser generator configured in this manner, when a high-repetition pulse voltage (1-I pulse) is applied, the following steps occur: HV pulse → peaking capacitor 4a → pre-ionization electrode 3a → pre-ionization Current flows through the 1%N3b→peaking capacitor 4b circuit, and ultraviolet rays are generated. Electrons generated by photoionization by the ultraviolet rays are used to make the main discharge between the first main electrode 1 and the second main electrode 2 into a glow-like uniform discharge.

However, in the conventional high-repetition pulse laser oscillation device as shown in (a) above, the density of electrons ionized by the ultraviolet rays generated by pre-ionization is '107/cm.
3, and since strong pre-ionization was performed at once, the pre-ionization electrode 3a.

Although the electron density near electrode 3b is high, since the pre-ionization electrodes 3a and 3b are arranged separately, the spatial density distribution of electrons between the two main electrodes 1 and 2 is uniform. First, the efficiency of the discharge between the main electrodes deteriorated, making it impossible to obtain a high output laser.

(Problems to be Solved by the Invention) As mentioned above, in the conventional high-repetition pulse laser oscillation device, the electron density generated by pre-ionization is small, and strong pre-ionization is performed at once. The spatial density distribution of electrons was not uniform, and a high output laser could not be obtained.

Therefore, the present invention was proposed to eliminate the above-mentioned drawbacks, and its purpose is to provide a high-power laser beam that is spatially uniform, capable of pre-ionization with high electron density, and capable of producing high-output laser light. The purpose of the present invention is to provide a repetitive pulse laser oscillation device.

[Structure of the Invention] (Means for Solving the Problems) The high-repetition pulse laser oscillation device of the present invention is provided with a high-speed pulse power source as a power source for generating preliminary ionization performed prior to main discharge. A rest period is provided between each pulse of the pulse train output from the high-speed pulse power supply, and
The high-speed pulse power source is connected to pulse pre-ionization electrodes provided on the first main electrode and the second main electrode, or connected between the first main electrode and the second main electrode arranged opposite to each other. I'll go.

(Function) According to the present invention having the above-described configuration, the electron density can be made uniform during the pause period between pulses from the high-speed pulse power source, and electrons can be generated by a plurality of pulses. Therefore, the electron density can be significantly increased, and the electron energy can be efficiently used not only for ignition of the main discharge but also for excitation of the laser gas.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 to 3. Incidentally, the same members as those of the conventional type shown in FIG. 4 are given the same reference numerals, and explanations thereof will be omitted.

■First embodiment Configuration of this embodiment* In this embodiment, as shown in FIG. 1, a second main N#A2 is disposed at a position facing the first main electrode 1,
A plurality of pre-ionization electrodes 3a are arranged at appropriate intervals on both sides of the first main electrode 1 in the longitudinal direction via a peaking capacitor 4a, and also on the second main electrode 2. A plurality of preliminary ionization electrodes 3b are provided on both sides in the longitudinal direction.
It is disposed at a position facing the pre-ionization electrode 3a via the peaking capacitor 4b.

Further, the two main electrodes 1 and 2 arranged opposite to each other are connected to a main pulse power source 5.

Roughly speaking, a pulse pre-ionization electrode 10a is arranged between the pre-ionization electrodes 3a arranged adjacently, and a pulse pre-ionization electrode 10a is arranged between the pre-ionization molds 4*3b arranged adjacently. Electrodes 10b are provided, each connected to a high-speed pulse power source 11.

Furthermore, optical resonators 6 are disposed at both longitudinal ends of the two opposing main electrodes 1 and 2, and a laser beam 71fi is output.

Effect of this embodiment* In the high repetition pulse laser oscillation device of this embodiment having such a configuration, as shown in FIG. , 2, a discharge first occurs between the preliminary ionization electrodes 3a and 3b. The main electrode 1 is exposed to the ultraviolet rays generated by this discharge.
, 2 while pre-ionizing the peaking capacitor 4a,
Charge is stored in 4b.

On the other hand, a high-speed, high-voltage pulse train is applied from the high-speed pulse power source 11 to the gap between the pulse pre-ionization electrodes 10a and 1ob, causing discharge and producing ultraviolet rays.

In this way, in this embodiment, when the two preliminary ionizations proceed simultaneously and the electron density between the main N poles 1 and 2 becomes sufficiently high, a glow discharge is ignited between the two main electrodes 1 and 2. Laser oscillation occurs.

Figure 2 (A) shows the changes over time in the voltage waveforms of the above-mentioned pulse voltage, glow voltage at the main electrode, and power supply voltage, and Figure 2 (A>) shows the changes over time in the electron density in the main discharge region.
Shown in B). That is, as shown in FIG. 2 (A > (B)), when a pulse train with a pulse width Tp and a pause period Yr between each pulse is applied for an application time TS, the glow voltage Vq between the main electrodes is significantly increased. , and the electron density also increases.

However, since a rest period Tr is provided between each pulse, electrons recombine during this period and the electron density temporarily decreases, but the density distribution is made uniform due to the electron diffusion effect. In addition, since electrons are generated again by the next pulse, the electron density gradually increases as shown in Figure 2 (B), and when the electron density reaches about 1010 or more (To
), the main discharge ignites. In addition, in this case, the power supply voltage VS
is always constant.

As described above, according to this embodiment, since the electron density generated by pre-ionization is sufficiently high, the energy used when the main discharge is ignited between the main electrodes is small, and the peaking capacitors 4a and 4b are The stored energy is
Since most of it is used to excite the laser gas, it is possible to generate high-output laser oscillation.

■Second Embodiment Configuration of this Embodiment* In this embodiment, as shown in FIG. A high-speed pulse power source 11 and a main pulse power source 12 are connected to the main electrodes 1 and 2.

Further, a main capacitor 13 is disposed in the main pulse power supply 12, and this main capacitor 13 is connected to the rail gap 14,
It is configured so that power can be supplied between the main electrodes 1 and 2 via the pulse matching circuit 15.

Effect of this embodiment* In the high repetition pulse laser oscillation device of this embodiment having such a configuration, as shown in FIG.
The electron density between the main electrodes 1 and 2 gradually increases due to a high-speed pulse train sent from a high-speed pulse power source 11 disposed between the main electrodes 1 and 2. When the electron density between the main electrodes 1 and 2 becomes sufficiently high (more than 10"/cm+), the rail gap 14 in the main pulse power source 12 is connected to the trigger laser beam 1.
Irradiate at step 6 to make it conductive. Then, main capacitor 1
The current stored in 3 begins to flow. Further, the pulse matching circuit 15 is a circuit that performs impedance matching between the capacitor side and the main electrode side, and can supply energy to the main discharge section with high efficiency and high speed.

In this way, in this embodiment, first, preliminary ionization is caused between the main electrodes 1 and 2 by a pulse train from the high-speed pulse power source 11, and when the electron density between the main electrodes 1 and 2 becomes sufficiently high, the two main electrodes A glow discharge is ignited between electrodes 1 and 2,
Laser oscillation occurs.

Note that the same effects as in the first embodiment can be obtained in this embodiment as well. That is, since there is a pause period Tr between each pulse of the pulse train from the high-speed pulse power source 11, electrons recombine during this period and the electron density temporarily decreases, but due to the electron diffusion effect, The electron density distribution between the main electrodes is made uniform. Further, since electrons are generated again by the next pulse, the electron density gradually increases as shown in FIG. 2(B), and when the electron density reaches about 1010 or more, the main discharge is ignited.

In this way, according to this embodiment, the electron density generated by pre-ionization is sufficiently high, so the energy used when the main discharge is ignited between the main electrodes is small, and the energy used in the main pulse power supply 12 is small. Since most of the energy stored in the main capacitor 13 is used to excite the laser gas, high-output laser oscillation can be caused.

Roughly speaking, in this embodiment, the main discharge start time is determined by the laser trigger, so the main discharge can be started in a state where the electron density is higher, and the output of the laser light is significantly increased.

[Effects of the Invention] As described above, according to the present invention, a high-speed pulse power source is provided as a power source for generating preliminary ionization performed prior to main discharge, and the pulse train output from this high-speed pulse power source is To provide a high-repetition pulse laser oscillation device capable of obtaining high-output laser light that is spatially uniform and capable of pre-ionization with high electron density by a simple means of providing a pause period between each pulse. be able to.

[Brief explanation of the drawing]

Figure 1 shows the first part of the high repetition pulse laser oscillation device of the present invention.
A perspective view showing an embodiment, FIG. B) is a diagram showing the change over time in the electron density in the main discharge region, FIG. 3 is a circuit diagram showing another embodiment of the present invention, and FIG. 4 is a perspective view showing the configuration of a conventional high repetition pulse laser oscillation device. It is a figure. 1... First main electrode, 2... Second main electrode, 3a. 3b... Pre-ionization electrode, 4a, 4b... Peaking capacitor, 5... Main pulse power supply , 6...Vanguard (Tatsuki), 7...Laser beam, 10a, 10b...Pulse pre-ionization electrode, 11...High speed pulse power supply, 12...Main pulse power supply, 13...Main capacitor , 14...Rail gap, 15...Pulse matching circuit, 16...Trigger laser light.

Claims (3)

[Claims] (1) A high-repetition pulse laser oscillation device that includes a first main electrode and a second main electrode placed opposite to the first main electrode, and causes a main discharge between the two main electrodes. A high-speed pulse power source is provided as a power source for generating preliminary ionization performed prior to the main discharge, and a rest period is provided between each pulse of the pulse train output from the high-speed pulse power source. High repetition pulse laser oscillation device. (2) The high-speed pulse power source is connected to the first main electrode and the second main electrode.
2. A high repetition pulse laser oscillation device according to claim 1, which is connected to a pulse pre-ionization electrode provided on a main electrode of. (3) The high-speed pulse power source is connected to the first
A high repetition pulse laser oscillation device according to claim 1, which is connected between a main electrode and a second main electrode.