JPS639675B2 - - Google Patents

Description

[Detailed Description of the Invention] A gas laser excites gas sealed in an airtight container by gas discharge, causing the excited gas molecules and gas atoms to resonate, and has excellent monochromaticity.
Light with qualitatively different coherences can be obtained.

In order to obtain a high-intensity laser, the gas discharge must be generated simultaneously and uniformly along the optical path within the resonator. For this purpose, a laser tube is used in which two parallel electrodes with a narrow gap are provided in an airtight container filled with a desired gas.

Such a laser tube produces a uniform discharge along the electrode when the pressure of the filler gas is relatively low, but when the pressure is high it produces a streamer-like arc discharge, ie a localized discharge on a portion of the electrode.

In order to prevent such local discharge and generate a uniform discharge along the electrodes, in addition to the two parallel electrodes with a narrow gap described above (hereinafter referred to as main discharge electrodes), A method has been used in which an auxiliary discharge electrode is provided, and the auxiliary discharge electrode is discharged prior to the discharge by the main discharge electrode, and after sufficient ions are generated, the main discharge electrode is discharged.

Below, using Figures 1, 2 and 3,
The structure of the laser tube according to the present invention will be explained.

FIG. 1 is a longitudinal cross-sectional view of the laser tube 20, in which linear electrodes 26 and 27 are placed inside a bottomed cylindrical airtight container 25.
is provided parallel to and near the cylinder axis. The electrodes 26 and 27 are the main discharge electrodes.
This laser tube 20 contains a mixed gas of 5% krypton, 94.8% helium, and 0.2% fluorine (pressure ratio).
It is sealed at 2.5 atm. 28 is an auxiliary discharge electrode,
It is provided on the inner wall of the airtight container 25 when the gap between the main discharge electrodes 26 and 27 shown in FIG. 2, which is a sectional view taken along the line AA in FIG. 1, is viewed from the maximum viewing angle. FIG. 3 is a longitudinal cross-sectional view showing the structure of the auxiliary discharge electrode, in which a conductive layer 3 continuous in the longitudinal direction is provided on the first surface of the electrically insulating substrate 29.
0, the conductive layer 30 is connected to the conductive layer 31 on the second surface at one end of the substrate 29, and the conductive layer 30 is connected to the conductive layer 31 on the second surface.
Island-shaped conductive layers 32 . . . 39 are electrically erected and arranged in a line on the surface. The auxiliary discharge electrode 28 is
The island-shaped conductive layers 32...39 are connected to the main discharge electrodes 26 and 27.
The conductive layer 30 is fixed to the airtight container 25 facing the gap and facing the inner wall of the airtight container 25.
A lead-in wire 40 is connected to the conductive layer 31, and a lead-in wire 41 is connected to the island-shaped electrode 39 located farthest from the conductive layer 31, so that a voltage can be applied from outside the airtight container 25. When a DC high voltage is applied to the lead-in wire 40 and the lead-in wire 41, the island-shaped conductive layers 39 and 3 first
8, the discharge develops sequentially, and discharge occurs between adjacent island-shaped conductive layers 31 to 39, ionizing the enclosed gas.

In the laser tube as described above, the main discharge electrode 2
A high voltage of 25 kilovolts or more is applied between 6 and 27 to generate laser light. At this time, the auxiliary discharge electrode 28 is provided parallel to the main discharge electrodes 26 and 27, and usually the main discharge electrode 26 or 27 Since it is given the same potential as either of the
Discharge tends to occur between the auxiliary discharge electrode 28 and one main discharge electrode, and at that time the main discharge electrodes 26 and 27
Since no discharge occurs or an extremely weak discharge occurs between the two, laser light cannot be generated.

The present invention relates to a discharge electrode circuit for a laser tube which eliminates the above-mentioned drawbacks.

The present invention is a discharge power supply circuit for a laser tube that does not cause unnecessary discharge between the auxiliary discharge electrode and the main discharge electrode as described above.

The present invention will be explained in detail by comparing the conventional discharge power supply circuit for a laser tube shown in FIG. 4 with the discharge power supply circuit for a laser tube according to the present invention shown in FIG. In FIG. 4, 20 is a laser tube, 26 and 27 are its main discharge electrodes, and 31 and 39 are its auxiliary discharge electrodes. 1 is the first inductor of 5 microhenries,
2 is the first capacitor of 16 nanometers, 3 is also
In the second capacitor of 16 nanoparticles, the first inductor 1, the first capacitor 2, and the second capacitor 3 are connected in series to form a closed circuit.
Both ends of the first inductor are connected to main discharge electrodes 26 and 27 of the laser tube 20, respectively. Connected to both ends of the second capacitor 3 are a first switch 4 that can withstand high voltages, such as a triggered spark gap, and a first DC high voltage power source 5 that outputs a voltage of 25 kilovolts. The above circuit constitutes a main discharge power supply circuit, and when a trigger signal is input to the trigger terminal of the first switch 4, the charges accumulated in the first capacitor 2 and the second capacitor 3 are transferred to the first inductor 1. high voltage is generated across it. 8 is the third capacitor of 6 nanometers, 6 is the second inductor of 10 microhenries, 9 is the second switch that can withstand high voltage such as a triggered spark gap, and the third capacitor 8 and the second inductor 6 and second switch 9
are connected in series in the above order to form a closed circuit. Both ends of the second inductor 6 are connected to auxiliary discharge electrodes 31 and 39 of the laser tube 20, respectively. A second DC high voltage power supply 10 that outputs a voltage of 20 kilovolts is connected to both ends of the second switch 9. The above circuit constitutes an auxiliary discharge power supply circuit,
When a trigger signal is input to the trigger terminal of the second switch 9, the charge accumulated in the third capacitor 8 flows through the second inductor 6, and a high voltage is generated across the second inductor 6.

Next, the operation when emitting laser light will be explained.

When you first input the trigger signal to switch 9,
A high voltage pulse is applied between the auxiliary discharge electrodes 31 and 39, and a discharge current flows between the auxiliary discharge electrodes 31 and 39 with a delay of approximately 0.1 microsecond from the trigger signal. As a result, the gas enclosed around the auxiliary discharge electrode is ionized and diffuses after about 1 microsecond to reach the gap between the main discharge electrodes. At this time, when a trigger signal is input to the switch 4, a high voltage pulse is applied to the main discharge electrodes 26 and 27, a uniform discharge is generated along the main discharge electrodes, and the energy state of gas molecules and atoms becomes a state of population inversion. Light generated when gas molecules or atoms in an excited state return to the ground state oscillates as a laser in a resonator consisting of an inverting mirror (not shown).

By the way, FIG. 5 is a graph showing the potential of each electrode with the main discharge electrode 27 as a reference. The potential curve of each electrode is indicated by the same reference numeral as the reference numeral indicating each electrode in FIG. In the figure, the extreme value shown at 0.1 microseconds is the potential of the auxiliary discharge electrode for generating auxiliary discharge. Further, the extreme value shown at 1 microsecond is the potential of the main discharge electrode for generating the main discharge. That is, a maximum of 50 kilovolts is applied between the auxiliary discharge electrode and the main discharge electrode 26 for 1 microsecond, and a discharge may occur during that time.
At this time, no discharge occurs between the main discharge electrode 26 and the main discharge electrode 27, or even if it occurs, it is extremely weak and cannot cause laser emission.

FIG. 6 is a diagram showing a specific example of a discharge power supply circuit for a laser tube according to the present invention. In the conventional discharge power supply circuit for a laser tube shown in FIG. and first capacitor 2
and the connection point between the third capacitor 8 and the second inductor 6 of the auxiliary discharge power supply circuit are connected via the fourth inductor 11 of 2 microhenries, and the above-mentioned connection of the second inductor 6 is made. A terminal different from the point is inserted between the DC high voltage power supply via the third inductor 7. In the circuit shown in FIG. 6, a trigger signal is input to the second switch 4, and a maximum voltage of 50 kilovolts is applied between the main discharge electrodes 26 and 27. At this time, the main discharge electrode 2
6 is the fourth inductor 11 and the second inductor 6
and grounded via the third inductor 7, a maximum of 50 kilovolts is applied to the auxiliary discharge electrode 31 and the auxiliary discharge electrode 39, and a maximum of 50 kilovolts is applied to the fourth inductor 11, the second inductor 6, and the third inductor 7. A potential divided by impedance is applied. That is, as shown in FIG. 7 by a curve in which the potential of each electrode in FIG. and the main discharge electrode 26 is 8 kilovolts, and the voltage between the auxiliary discharge electrode 39 and the main discharge electrode 27 is reduced to 4 kilovolts. Therefore, no discharge occurs between the auxiliary discharge electrode and the main discharge electrode, and stable laser emission can be obtained.

As specifically explained above, the present invention provides the first
The inductor 1, the first capacitor 2, and the second capacitor 3 are connected in series to form a closed circuit.
A switch 4 is connected to both ends of the first capacitor 2 or the second capacitor 3, and a DC high voltage power source is connected to both ends of the first capacitor 2 or the second capacitor 3. 5 is connected to the main discharge power supply circuit, and the third capacitor 8
The second inductor 6, the third inductor 7, and the switch 9 are connected in series in the above order to form a closed circuit, and both ends of the second inductor 6 are connected to the auxiliary electrodes 31 and 39 of the laser tube 20, respectively. and an auxiliary discharge power supply circuit with a second DC high voltage power supply 10 connected to both ends of the switch 9 and the first inductor 1.
A discharge power source for a laser tube, characterized in that a connection point between the capacitor 8 and the first capacitor 2, and a connection point between the third capacitor 8 and the second inductor 6 are connected via a fourth inductor 11. The circuit prevents discharge between the auxiliary discharge electrode and the main discharge electrode, and enables stable laser emission.

Note that in the above circuit, the third inductor 7
When is made larger than the fourth inductor 11,
This is not appropriate because the current for the auxiliary discharge no longer flows between the auxiliary discharge electrode 31 and the auxiliary discharge electrode 39, making the auxiliary discharge extremely weak.

In addition, in FIG. 6, the first capacitor 2 and the second capacitor
For the capacitor 3, the first inductor 1 is connected to the fourth inductor 11, the second inductor 6, and the third inductor 1.
The inductance of the first inductor 1 is approximately equal to the inductance of the fourth inductor 11, the second inductor 6, and the third inductor 7, so this is omitted. be able to.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional structural diagram of the laser tube, FIG. 2 is a longitudinal cross-sectional structural diagram of the laser tube shown in FIG. 1, and FIG. 3 is a longitudinal cross-sectional structural diagram of the auxiliary discharge electrode 28 of the laser tube shown in FIG. , Fig. 4 is a circuit diagram of a conventional laser tube discharge power supply, and Fig. 5 shows each voltage applied to the laser tube by the conventional laser tube discharge power supply shown in Fig. 4. Figure 6 is a diagram showing the potential of the electrodes, Figure 6 is a circuit diagram of the discharge power source for the laser tube of the present invention, and Figure 7 is a diagram showing voltage applied to the laser tube by the discharge power source for the laser tube of the present invention shown in Figure 6. FIG. 3 is a diagram showing the potential of each electrode at the time.

Claims (1)

[Claims] 1. A first inductor, a first capacitor 2, and a second capacitor 3 are connected in series, and both ends of the first capacitor 2 and second capacitor 3 are connected to the main discharge of the laser tube 20, respectively. A switch 4 is connected to the electrodes 26 and 27, a switch 4 is connected to both ends of the first capacitor 2 or the second capacitor 3, and a DC high voltage power source 5 is connected to both ends of the first capacitor 2 or the second capacitor 3. The main discharge power supply circuit, the third capacitor 8, the second inductor 6, the third inductor 7, and the switch 9 are connected in series in the above order to form a closed circuit, and both ends of the second inductor 6 are connected in series. are connected to the auxiliary electrodes 31 and 39 of the laser tube 20, respectively, and a second DC high voltage power source 10 is connected to both ends of the switch 9, and the main discharge electrode 26 of the discharge tube 20 and the first capacitor 2
A discharge power supply circuit for a laser tube, characterized in that a connection point between the third capacitor 8 and the second inductor 6 is connected via a fourth inductor 11. 2. The discharge power supply circuit for a laser tube according to claim 1, wherein the inductance of the fourth inductor 11 is larger than the inductance of the third inductor 7.