JPH04109684A - Metal vapor laser device - Google Patents

Abstract

PURPOSE:To widen a pulse width of a laser output beam without lowering a mean output value of laser beam by connecting in parallel a peaking capacitor and a delay capacitor and connecting in series a delay inductor with the delay capacitor. CONSTITUTION:A peaking capacitor 3 is connected in prallel with a discharge tube 4, charging energy of capacitor 3 is supplied to the discharge tube 4 and laser oscillation is generated with such discharge energy. A delay capacitor 10 is connected in parallel with the peaking capacitor 3 and a delay inductor 11 is connected in series with a delay capacitor 10. Namely, a rising part of discharge current flowing into the discharge tube 4 is compensated by the peaking capacitor 3 and a field sustaining time can be elongated by the delay capacitor 10. Thereby, a longer duration pulse can be obtained, while reduction of laser output beam is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a pulse discharge excitation type metal vapor laser device using metal vapor as a laser medium.

(Prior Art) Conventionally, the electric circuit of a metal vapor laser device is configured as shown in FIG. A discharge method is adopted in which the battery is charged and discharged into the discharge tube 4 while being controlled by the capacity of the peaking capacitor 3, and the discharge energy causes laser oscillation.

Note that 5 and 6 are distributed inductors.

In recent years, there has been a demand for higher output from metal vapor laser devices, and since there is a limit to the average output that can be obtained from a single laser device, a laser oscillator 7 and laser amplifiers 8a and 8b are connected in series as shown in FIG. A multi-stage amplification method is used to obtain high laser output. In this method, matching the oscillation timing of each laser device and the optical pulse width is an important condition in terms of improving the amplification efficiency of laser light.

(Problems to be Solved by the Invention) By the way, the laser oscillator 7. Both the laser amplifiers 8a and 8b employ the above-mentioned discharge method. Although this discharge method provides an output equivalent to that of a single laser device, the optical pulse width of the laser oscillator 7 is equal to the optical pulse width of the laser amplifiers 8a and 8b. The amplification efficiency is poor because it is relatively short. Therefore, it is necessary to widen the optical pulse width of the laser oscillator 7 to approximately the optical pulse width of the laser amplifiers 8a and 8b.

Incidentally, the rise and sustain time of the discharge that serves as the excitation source of the metal vapor laser is determined by the capacitance of the peaking capacitor 3. If the capacitance of the peaking capacitor 3 is reduced using the electric circuit of a conventional metal vapor laser device, high laser power can be obtained, but the pulse width will become narrower.
Conversely, if the capacitance is increased, the desired pulse width can be obtained, but there is a problem in that the laser output is extremely reduced.

The present invention has been made in consideration of the above-mentioned circumstances, and it is an object of the present invention to provide a metal vapor laser device that can widen the laser output light pulse width without reducing the laser output.

[Structure of the invention]

(Means for Solving the Problem) In order to achieve the above object, a metal vapor laser device according to the present invention! In this metal vapor laser device, a peaking capacitor is connected in parallel with the discharge tube, and the charge energy of this capacitor is supplied to the discharge tube, and the discharge energy is used to generate laser oscillation. A further feature is that a delay inductor is connected in series with this delay capacitor.

(Function) In the metal vapor laser device of the present invention, the rise of the discharge current flowing into the discharge tube is compensated for by the peaking capacitor, and the electric field maintenance time is extended by the delay capacitor. This makes it possible to achieve

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3.

Note that the same reference numerals as in FIG. 4 are used to describe parts that are the same as or correspond to the conventional structure.

FIG. 1 shows an electric (discharge) circuit diagram of a metal vapor laser device, in which a charging capacitor 1. The switch 2, the discharge tube 4, and the distributed inductor 6.5 are connected in series to form a closed circuit, and the peaking capacitor 3 is connected in parallel to the discharge tube 4. The peaking capacitor 3 is used to reduce the inductor distributed in the electric circuit as much as possible.
It is removably connected to the discharge tube 4 by making the current loop with the discharge tube 4 as short as possible.

A delay circuit 9 is provided in parallel with this peaking capacitor 3. The delay circuit 9 includes a delay capacitor 10 and a delay inductor 11 connected in series with the delay capacitor 10.

Further, a typical configuration example of the discharge tube 4 is illustrated in FIG.

An anode 23 is provided at both ends of the core tube 20 constituting the discharge tube 4.
and cathodes 24 are supported by electrode support flanges 25, 26 and are arranged opposite to each other. Then, pulsed bipolar discharge is performed in the discharge space 27 formed between the anode 23 and the cathode 24. A metal vapor source 28 such as copper grains is arranged at the inner bottom of the furnace tube 20 .

A heat insulating layer 29 is formed on the outer periphery of the furnace core tube 20, and a protection tube 30 is provided on the outer periphery of the heat insulating layer 29 in order to fix and hold the heat insulating layer 29 in a predetermined position.

This protection tube 30 and the external vacuum container 3 arranged around its outer periphery
1 forms a vacuum insulation chamber 32. The vacuum insulation chamber 32 and the discharge space 27 in the reactor core tube 20 are connected to an exhaust device 33 to maintain a vacuum state inside.

A break tube 34 made of an insulating material is interposed between the external vacuum vessel 31 and the electrode support flange 26 in order to insulate the anode 23 and the cathode 24 and obtain a good discharge. Incidentally, Brewster windows 36 and 37 are provided on the outer end side in the axial direction of the electrode support flange 25°26. Resonant mirrors 39 and 40 constituting the resonator 38 are arranged on the outside thereof.

Next, the operation of this embodiment will be explained.

The charges charged in the charging capacitor 1 are charged in the peaking capacitor 3 and the delay capacitor 10 when the switch 2 becomes conductive. Further, the rise of the discharge current flowing into the discharge tube 4 can be compensated for by a fast current loop flowing from the peaking capacitor 3 through the distributed inductor 6 into the discharge tube 4, and also from the delay capacitor 10 to the delay inductor 112. A slow current loop flowing into the discharge tube 4 through the distributed inductor 6 applies an electric field to the discharge tube 4 for a long time, and the discharge current time can be maintained. In addition to the combination of the fast current loop and the slow current loop, the maximum current loop that is guided to the discharge tube 4 via the distributed inductor 6 while resonating between the peaking capacitor 3 and the delay capacitor 11 via the delay inductor 11 is also added. In addition, a slow current loop is also added. The rapid rise of the discharge current effectively suppresses the decrease in the average output and guarantees the rise of the discharge, while the long discharge current time maintains the electric field applied to the discharge tube, as shown by the solid line a in Figure 3. The laser output light can be made into a longer pulse than the conventional laser output light shown by the dashed line and the chain line C, and the pulse width of the laser output light can be increased by about 1.5 to 2 times at half maximum.

Also, to explain the operation of oscillating laser light, first,
The exhaust device 33 is operated to exhaust the inside of the vacuum insulation chamber 32 and the discharge space 27. Next, buffer gas supply source 3
A buffer gas such as neon gas is supplied from 5 into the discharge space 27 to maintain a constant pressure inside.

When the pulsed high voltage power supply shown in FIG. 1 is activated in this state, a pulsed high voltage is applied between the anode 23 and the cathode 24, and discharge plasma is generated in the discharge space 27.

Floating metal vapor collides with free electrons in the discharge plasma to excite the metal vapor, and when the excited metal vapor transitions to a lower energy level, a laser beam of a predetermined wavelength is generated. The laser light generated within the discharge space 27 passes through the Brewster windows 36 and 37, and further resonates between the output mirror 39 and the total reflection mirror 40 that constitute the resonator 38.
The output mirror 39 oscillates.

〔Effect of the invention〕

As explained above, according to the present invention, the delay capacitor is connected in parallel with the peaking capacitor, and the delay inductor is connected in series with the delay capacitor, so that the discharge current rises quickly and an electric field is applied to the discharge tube for a long time. This has the effect that the pulse width of the laser output light can be expanded without reducing the laser light average output value.

[Brief explanation of drawings]

FIG. 1 is an electric circuit diagram showing an embodiment of a metal vapor laser device according to the present invention, FIG. 2 is a sectional view showing the discharge tube of FIG. 1, FIG. 3 is a waveform diagram showing optical pulses, and FIG. The figure is an electric circuit diagram showing a conventional metal vapor laser device, and FIG. 5 is a block diagram showing the concept of a multistage amplification method. 1...Charging capacitor, 2...Switch, 3...
Peaking capacitor, 4...Discharge tube, 5.6...
Distributed inductor, 9... Delay circuit, 10... Delay capacitor, 11... Delay inductor. Figure 3: Room

Claims (1)

[Claims] In a metal vapor laser device in which a peaking capacitor is connected in parallel with a discharge tube, charging energy of this capacitor is supplied to the discharge tube and laser oscillation is performed by the discharge energy, a delay capacitor is connected in parallel with the peaking capacitor and this A metal vapor laser device characterized in that a delay inductor is connected in series with a delay capacitor.