JP2982791B1 - Microwave-excited gas laser oscillator - Google Patents

Abstract

An object of the present invention is to obtain a stable high-peak pulsed laser light output in a microwave-excited gas laser oscillation device. SOLUTION: The switching drive of a high voltage switching power supply is all operated by the same drive signal, the injection variation of each magnetron is feedback-controlled by the voltage control of the constant voltage power supply section, and the first pulsating flow of the magnetron current is ignored. By taking a feedback signal and performing feedback control of the magnetron current, a stable high peak pulsed laser light output can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave gas laser oscillator for exciting microwave discharge.

[0002]

2. Description of the Related Art In recent years, there has been a trend toward miniaturization of gas laser oscillation devices, and as a means therefor, a higher excitation frequency has been promoted. Conventionally, DC and a high-frequency power supply of several hundreds of kHz to several tens of MHz have been used as a power supply for the gas laser oscillator, but there are problems in price and controllability.
At present, various studies have been made on microwave-excited gas laser transmitters.

Hereinafter, a conventional microwave gas laser oscillation device will be described with reference to the drawings. FIG. 5 is a schematic diagram showing a configuration of a conventional microwave gas laser oscillation device. In FIG. 5, 1 is a magnetron for generating a microwave, 2 is a waveguide for transmitting a microwave, 3 is a discharge tube in which a laser gas flows, 4 is a microwave power supply for driving the magnetron 1, and 8 is a laser beam. Is a total reflection mirror that forms an optical resonator with the output mirror 8. The microwave power supply 4 includes a constant voltage power supply 40 and a high voltage switching power supply 41.

The operation of the above configuration will be described. The constant voltage power supply 40 is controlled to a constant voltage, outputs a constant DC voltage, and supplies it to the high voltage switching power supply 41. With this constant voltage power supply 40, a stable laser light output can be obtained. Each high-voltage switching power supply 41 is a switching power supply of about 20 kHz, receives an output command and a synchronization signal, and applies a oscillating high voltage to the magnetron 1 by a switching signal according to the output command. At this time, the high-voltage booster 42 is configured so that the magnetron current output from the high-voltage switching power supply 41 has a pulsating waveform having a complete off-time, and all magnetron current waveforms are synchronized. I have. The microwave emitted from the magnetron 1 is injected into the discharge excitation unit 10 via the waveguide 2. Laser light emitted from the laser gas excited by the discharge excitation unit 10 is output from the output mirror 8 and the total reflection mirror 9.
And a part thereof is taken out of the output mirror 8. The high-voltage switching power supply 41 detects the magnetron current with the magnetron current detection element 42 and performs PWM control so as to keep the magnetron current constant.

[0005]

In such a conventional microwave gas laser oscillator, since the high voltage switching power supply is driven by PWM control, the phase at the peak of the pulsating magnetron current is delicate. In contrast, there is a problem that the peak value of the laser light output is lower than in the case where the phases are completely matched. Further, at the time of intermittent oscillation of laser light, there is a problem that the output of laser light fluctuates when the frequency of intermittent oscillation is different.

An object of the present invention is to provide a microwave gas laser oscillation device capable of stably outputting a high peak pulse.

[0007]

In order to achieve the above object, the present invention according to the first aspect of the present invention is directed to a discharge system in which a laser gas flows.
Tube and magnetron for supplying microwaves to the discharge tube
And a constant voltage power supply and the power supplied from the constant voltage power supply.
High voltage switching power supply to supply power to magnetron
A plurality of microwave power supplies having
Of the magnetron current flowing between the anode and cathode of
Ignore the initial pulsation and take the feedback signal
This is a microwave-excited gas laser oscillation device that performs feedback control of the tron current .

[0008]

[0009]

According to a second aspect of the present invention, there is provided a discharge tube through which a laser gas flows, a magnetron for supplying a microwave to the discharge tube, a constant voltage power supply, and power supplied from the constant voltage power supply to the magnetron. A plurality of microwave power supplies having a high-voltage switching power supply, and when obtaining an intermittent output of laser light, the constant-voltage power supply outputs a feedback signal ignoring the first pulsating flow of the magnetron current flowing between the anode and the cathode of the magnetron. This is a microwave-excited gas laser oscillation device to be input to the device.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claims 1 and 2
Magnet flowing between the magnetron anode and cathode
Ignoring the first pulsating current of the
Feedback control of the magnetron current
This has the effect that a laser beam having an intermittent output with a fast rise and a high peak can be obtained.

[0012]

(Embodiment) Hereinafter, a gas laser oscillation device will be described with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration example . The same components as those in the conventional example are given the same numbers. FIG.
, A discharge tube 3 in which a laser gas flows is inserted into N (N ≧ 1) microwave waveguides 2, and the discharge excitation unit 1 is irradiated with microwaves output from the magnetron 1.
At 0, a microwave glow discharge is formed. Also,
The N magnetrons 1 are controlled by respective N microwave power supplies. Here, one of the N microwave power supplies is a master microwave power supply 4a, the remaining microwave power supplies are slave microwave power supplies 4b, and the constant voltage power supplies 40a and 40b and the high voltage switching power supply 41a are respectively included in the respective microwave power supplies. , 41b. The master microwave power supply 4a receives the output command, generates a switching signal S1 for determining the ON time of the switching element of the master high-voltage switching power supply 41a, and drives the magnetron. The magnetron current output from the master high-voltage switching power supply 41a and flowing between the anode and cathode of the magnetron is detected by the master current detecting element 42a, and the master constant voltage power supply 40a performs feedback control on the output voltage so that the magnetron current value becomes the output command value. This is to prevent the magnetron current from drifting even with the same switching signal due to a change in the temperature of the magnetron. All the slave microwave power supplies 4b receive the switching signal S1 of the master high voltage switching power supply 41a of the master microwave power supply 4a, and the slave high voltage switching power supply 41b operates and drives the magnetron with the same switching signal S1. The magnetron current output from the slave high voltage switching power supply 41b is detected by the slave current detection element 42b, and the slave constant voltage power supply 40b performs feedback control on the output voltage so that the magnetron current value becomes the output command value. When the microwave power supply is configured in this manner, as shown in FIG. 2, the same energy is generated within the same time during which the ON time and the phase of all the magnetron currents that operate in a pulsating manner are the same as in the conventional PWM control of the high voltage switching power supply. Since the light is injected into the discharge tube, the light output also has a high intermittent output with a fast rising peak.

Hereinafter, features of the gas laser oscillation device according to the present invention will be described with reference to the drawings. In general, the magnetron starts oscillating when a high voltage of about 4 kV is applied between the anode and the cathode, but an LC filter is inserted in an input portion for preventing microwave leakage. FIG. 3 shows a magnetron current waveform when the frequency at the time of the intermittent output is different. When the frequency is low, the magnetron voltage is low, so that the current flowing into the capacitor of the LC filter increases, and even with the same high-voltage switching power supply switching signal, an error occurs in the magnetron current detection signal depending on the frequency. Therefore, the first pulsating magnetron current at the time of the intermittent output is ignored, and the magnetron current after the second is used as the magnetron current detection signal. FIG. 4 shows the frequency characteristics of the laser light energy at the time of intermittent output. Conventionally, when all the magnetron currents are feedback-controlled as magnetron current detection signals, the first magnetron current flows excessively at low frequencies, so feedback control was performed to reduce the entire magnetron current, resulting in light energy However, when the first magnetron current is ignored and the second and subsequent magnetron currents are feedback-controlled as magnetron current detection signals, substantially constant laser light energy is obtained irrespective of the frequency.

[0015]

As is apparent from the above description, according to the present invention, it is possible to provide a microwave-excited gas laser oscillation device capable of obtaining a stable high peak laser beam.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a microwave gas laser oscillation device used in the present invention.

FIG. 2 is a comparison diagram of a switching signal, a magnetron current waveform, and a laser beam waveform of each part in the same configuration example with a conventional one.

FIG. 3 is a magnetron current waveform diagram when a pulse frequency changes.

FIG. 4 is a diagram illustrating a comparison between a frequency characteristic of laser light energy and a conventional method according to an embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a conventional microwave gas laser oscillation device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetron 2 Waveguide 3 Discharge tube 4a Master microwave power supply 4b Slave microwave power supply 40a Master constant voltage power supply 40b Slave constant voltage power supply 41a Master high voltage switching power supply 41b Slave high voltage switching power supply 42a Master current detecting element 42b Slave current detecting element 8 Output Mirror 9 Total reflection mirror 10 Discharge excitation section S1 Switching signal S2 Magnetron current detection signal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-273389 (JP, A) JP-A-9-148663 (JP, A) JP-A-9-326517 (JP, A) JP-A 8- 123520 (JP, A) JP-A-5-306038 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3/097

Claims (2)

(57) [Claims] 1. A discharge tube through which a laser gas flows, a magnetron that supplies microwaves to the discharge tube, a constant voltage power supply, and a high voltage switching power supply that is supplied with power from the constant voltage power supply and supplies power to the magnetron. A microwave-excited gas laser oscillation device comprising a plurality of microwave power supplies, and ignoring the first pulsating magnetron current flowing between the anode and cathode of the magnetron, taking a feedback signal and performing feedback control of the magnetron current. 2. A discharge tube through which a laser gas flows, a magnetron for supplying microwaves to the discharge tube, a constant voltage power supply, and a high voltage switching power supply supplied with power from the constant voltage power supply and supplying power to the magnetron. A microwave-excited gas laser that inputs a feedback signal to the constant-voltage power supply, ignoring the first pulsating flow of the magnetron current flowing between the anode and the cathode of the magnetron when obtaining a discontinuous output of the laser light. Oscillator.