WO1999060676A1 - Dispositif laser a gaz pulse - Google Patents
Dispositif laser a gaz pulse Download PDFInfo
- Publication number
- WO1999060676A1 WO1999060676A1 PCT/JP1999/002584 JP9902584W WO9960676A1 WO 1999060676 A1 WO1999060676 A1 WO 1999060676A1 JP 9902584 W JP9902584 W JP 9902584W WO 9960676 A1 WO9960676 A1 WO 9960676A1
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- electrode
- discharge path
- gas laser
- main electrode
- voltage
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Classifications
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- 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
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
- H01S3/09705—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser with particular means for stabilising the discharge
-
- 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
- H01S3/02—Constructional details
- H01S3/03—Constructional details of gas laser discharge tubes
-
- 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
- H01S3/02—Constructional details
- H01S3/03—Constructional details of gas laser discharge tubes
- H01S3/038—Electrodes, e.g. special shape, configuration or composition
Definitions
- the present invention relates to a pulse gas laser generator that generates a laser beam by discharging and exciting a gas laser medium.
- Ultraviolet pulse gas laser generators such as nitrogen (N 2 ) lasers and excimer lasers, are used for fluorescence analysis, remote sensing devices using gas absorption, etc., or photochemical reaction process applications. Used in laser devices.
- N 2 nitrogen
- excimer lasers used for fluorescence analysis, remote sensing devices using gas absorption, etc., or photochemical reaction process applications. Used in laser devices.
- a device using a lateral discharge excitation method by ultraviolet light preionization using a long electrode along the optical axis of laser oscillation has been put to practical use.
- the discharge region is difficult to be uniformly excited, and the laser output tends to fluctuate for each pulse.
- the cross section of the output laser beam is non-circular such as a rectangle. Efficiency is reduced.
- Japanese Patent Application Laid-Open Nos. 1-110389, Hei4-125187, Hei8-3169550, Hei9-310, and Hei9 There is a method that utilizes discharge excitation in the direction of the laser optical axis, that is, the vertical direction, as known in Japanese Patent Application Laid-Open No. 8-3002.
- the longitudinal discharge excitation method itself for example, H e - N e laser tube, Al Gonreza tube, is also known for C 0 2 laser tube.
- these usually start discharging by superimposing a high voltage pulse on the applied voltage.
- the pulse gas laser generator of the vertical discharge excitation type has a gas laser tube 11 and an operation start trigger voltage and an operation voltage. And a power supply device 12 electrically connected to supply power.
- the power supply device 12 has a high-voltage generator and a high-voltage trigger power supply, and is connected to the laser tube 11 via a storage capacitor 13.
- the laser tube 11 for example, nitrogen gas is sealed as a laser medium 14 at a predetermined pressure in a cylindrical insulating tube 11a which is a vacuum vessel. Furthermore, both ends of the insulating tube 11a are closed in a vacuum-tight manner by an output mirror 17 and a high-reflection mirror 18 and a cylindrical cathode 15 and an anode 16 serving as a pair of discharge electrodes are provided inside the vicinity thereof. Is provided.
- a high trigger voltage is supplied between the anode and the cathode from a trigger circuit in the power supply device 12, and the medium between the anode 16 and the cathode 15 is applied by application of the trigger voltage. Electrical breakdown occurs through the gas, and the electric charge stored in the storage capacitor 13 flows between the anode and the cathode, activating the laser medium. As a result, optical resonance occurs between the high reflection mirror 18 and the output mirror 17, and laser light is output from the output mirror 17.
- the above-described pulse gas laser generator of the vertical discharge excitation type has an advantage that an output laser beam having a circular cross section can be obtained.
- a considerably high trigger voltage and main discharge voltage must be supplied between the cathode and the anode.
- a phenomenon occurs in which a discharge current called a bright spot is locally concentrated on the cathode or the anode, and the material of the cathode or the anode may cause spalling.
- This sputtering has disadvantages such as lowering the laser oscillation efficiency by contaminating the mirror, or impairing the withstand voltage performance by adhering to the inner surface of the insulating tube constituting the main discharge path.
- An object of the present invention is to provide a pulse gas laser generator capable of performing high-repetition pulse oscillation without generating a bright spot on a main discharge electrode and obtaining an output laser beam having a circular cross section and a uniform intensity distribution. With the goal.
- a pulse gas laser generator has a The first main electrode, the cylindrical discharge tube made of an insulator for forming a main discharge path, and the second main electrode are arranged in tandem in this order, and a medium gas is accommodated therein.
- a pair of mirrors constituting an optical resonator is disposed outside the main electrode, and further comprising a power supply for applying a main discharge voltage between the first main electrode and the second main electrode.
- a cylindrical dielectric and an auxiliary electrode disposed adjacent to the cylindrical dielectric in the vicinity of at least one of the first main electrode and the second main electrode, and the cylindrical dielectric during operation.
- FIG. 1 is a longitudinal sectional view and a connection diagram of a main part showing an embodiment of the present invention.
- FIG. 2 is a schematic diagram illustrating the operation of the embodiment of FIG. 1 and a graph illustrating the magnitude of the applied voltage.
- FIG. 3 is a graph illustrating the operation of the embodiment of FIG.
- FIG. 4 is a graph illustrating a preferred embodiment of the present invention.
- FIG. 5 is a vertical sectional view of a main part showing another embodiment of the present invention.
- FIG. 6 is a vertical sectional view of a main part showing still another embodiment of the present invention.
- FIG. 7 is a vertical sectional view of a main part showing still another embodiment of the present invention.
- FIG. 8 is a longitudinal sectional view of a main part showing still another embodiment of the present invention.
- FIG. 9 is a longitudinal sectional view and a connection diagram of main parts showing still another embodiment of the present invention.
- FIG. 10 is a schematic structural diagram illustrating the operation of the embodiment in FIG.
- FIG. 11 is a schematic structural diagram showing still another embodiment of the present invention.
- FIG. 12 is a waveform diagram illustrating the operation of FIG.
- FIG. 13 is a schematic structural diagram showing still another embodiment of the present invention.
- FIG. 14 is a waveform diagram illustrating the operation of FIG.
- FIG. 15 is a longitudinal sectional view of a main part showing still another embodiment of the present invention.
- FIG. 16 is a longitudinal sectional view of a main part showing still another embodiment of the present invention.
- FIG. 17 is a longitudinal sectional view and a connection diagram of a main part showing still another embodiment of the present invention.
- FIG. 18 is a longitudinal sectional view and a connection diagram of a main part showing still another embodiment of the present invention.
- FIG. 19 is a schematic diagram illustrating a conventional example. DETAILED DESCRIPTION OF THE INVENTION Embodiments will be described below with reference to the drawings. The same parts are indicated by the same reference numerals.
- a nitrogen gas is sealed at a predetermined pressure as a medium gas for laser inside a discharge tube 21 made of a cylindrical insulating ceramic constituting a vacuum vessel of a pulse gas laser tube. .
- an output mirror 22 made of a glass plate having an output mirror film on the inner surface is bonded in a vacuum-tight manner, and on the right side of the discharge tube 21, a glass plate having a high reflection mirror film on the inner surface is provided.
- the high-reflection mirrors 23 are joined in a vacuum-tight manner to form an optical resonator.
- the discharge tube 21 constituting the main discharge path includes a first cylindrical portion 21 a made of insulating ceramics having the same inner diameter and a second cylindrical portion having the same inner diameter with an intermediate electrode 26 formed of a metal ring interposed therebetween. 21b are arranged in tandem in the laser optical axis direction and are air-tightly joined. An intermediate electrode cylindrical portion 26a made of a metal cylinder is arranged inside the portion of both cylindrical portions 21a and 21b joined to the intermediate electrode 26. Further, a metal exhaust pipe 26 b is connected to the intermediate electrode 26.
- a cathode 25 having an inner surface exposed to the discharge path is hermetically bonded to the left end of the first cylindrical portion 21a of the discharge tube in the figure, and a first outer conductor 3 extending from the cathode 25 is provided on the outer periphery. 1 are closely fitted.
- the other end 31b of the first outer conductor 31 is extended to a position corresponding to a position near the end of the intermediate electrode cylindrical portion 26a.
- a dielectric cylinder 40 made of a ceramic having a high dielectric constant is hermetically joined to the left of the cathode 25 in the figure, and an auxiliary electrode 41 made of a metal ring is hermetically joined to the left end thereof.
- the output mirror 22 is hermetically bonded to the auxiliary electrode 41.
- the cathode 25, the auxiliary electrode 41, and the dielectric cylinder 40 sandwiched between them form a plasma cathode 25a on the inner surface of the dielectric cylinder 40 and its inner region during operation. You.
- the first discharge path 20a is formed between the plasma cathode 25a and the intermediate electrode cylindrical portion 26a that face each other inside.
- An anode 24 made of a metal ring is airtightly joined to the right end of the second cylindrical portion 21b of the discharge tube in the figure, and a high reflection mirror 23 is airtightly joined to the tip of the anode 24.
- a second discharge path 20b is formed between the intermediate electrode cylindrical portion 26a and the anode 24 that face each other inside.
- the ratio of the axial lengths of the first discharge path 20a and the second discharge path 20b is set to be a predetermined ratio, as described later.
- the inside of the discharge tube 21 is evacuated by the exhaust tube 26b and then sealed in the discharge tube so that the nitrogen gas has a predetermined pressure. Thereafter, the exhaust tube 26b is cut off. Have been.
- a second outer conductor 32 is closely fitted around the outer periphery of the second cylindrical portion 21b of the discharge tube.
- One end 3 2a of the second outer conductor 32 is fixed to the anode 24 and electrically short-circuited, and the other end 32b corresponds to the vicinity of the end of the intermediate electrode cylindrical portion 26a. It is extended to the position where it does.
- a cylindrical coaxial storage capacitor 30 is coaxially arranged around the second cylindrical portion 21 b and the second outer conductor 32 of the discharge tube.
- the coaxial storage capacitor 30 has an inner electrode 30b and an outer electrode 30c adhered to the inner and outer surfaces of a cylindrical dielectric 30a made of a ceramic having a high dielectric constant. It has been.
- One inner circumferential electrode 3 Ob is directly connected to the left end 3 2b of the second outer conductor 32 by a conductive ring 34 having high conductivity and mechanical strength, and is electrically short-circuited. Have been.
- the other outer peripheral electrode 30 c is grounded together with the negative electrode of the first power supply device 27 as a ground electrode. Further, the inner peripheral electrode 30 b of the coaxial capacitor 30 is electrically connected to the positive terminal of the first power supply device 27.
- the positive electrode side of the coaxial storage capacitor 30 that accumulates the charge for the main discharge is connected to the tip end of the second outer conductor 32 that is disposed close to the intermediate electrode of the gas laser tube by the conductor ring 34.
- b is directly connected to the entire outer periphery and electrically short-circuited.
- the conductor ring 34 also has a function of mechanically holding the coaxial capacitor 30 in the laser tube, and the coaxial capacitor 30 is covered with an insulating resin (not shown).
- the intermediate electrode 26 and the auxiliary electrode 41 on the cathode side are supplied with high-resistance elements 29 a and 29 b for limiting the trigger current from the second power supply unit 28 through the pulse-like trigger.
- Re It is electrically connected so that a gas voltage is supplied.
- the second power supply device 28 generates a control trigger pulse voltage corresponding to the repetition frequency of the pulsed laser oscillation, and includes an internal power supply, a pulse transformer, and the like. Then, the second power supply device 28 is connected so as to supply a trigger pulse voltage to the intermediate electrode 26 ( the drive control method and operation example of the laser generator shown in FIG. The distance La shown in (a) of Fig.
- each discharge path formed in each discharge tube cylinder is sufficiently larger than the diameter of the discharge path, that is, the inner diameter of each discharge tube cylinder.
- a dielectric material on the inner surface and the inner area where a plasma cathode 25a is generated during operation The axial length of the tube 4 0, less than half of the axial length of the first discharge passage 2 0 a (L a), and more preferably is set to less than one third.
- a DC voltage lower than the self-discharge starting voltage, that is, the anode 24, is supplied from the first power supply device 27.
- a positive voltage (+ V o) is applied.
- the anode 24 is connected to the first power supply device 2 via the second outer conductor 32, the conductor ring 34, and the inner peripheral electrode 30b of the coaxial capacitor 30. 7 is connected to the positive electrode.
- the cathode 25 is grounded via the first outer conductor 31.
- This potential gradient E o is a value that does not cause self-discharge in the discharge path, that is, a potential gradient that does not cause a main discharge with this potential gradient unless there is a corona discharge anywhere in the discharge path and a pre-ionization region. .
- a negative pulse-like trigger voltage (1 Vt) is applied to the intermediate electrode 26 from the second power supply device 28 via the resistor 29a.
- a negative pulse-like trigger voltage (1 Vt) is applied to the auxiliary electrode 41 from the second power supply device 28 via the resistor 29b.
- a voltage applied between the cathode 25, which is the ground potential, and the auxiliary electrode 41 is applied. Due to the trigger voltage (-Vt), a plasma cathode 25a is generated on the inner surface of the dielectric cylinder 40 and its inner region.
- the absolute value of the potential gradient E b in the second discharge path between the intermediate electrode 26 and the anode 24, that is, in the second cylindrical portion 21 b is approximately (E b 2 (IV o I + IV t I ) / L b), and is indicated by a straight line E b in FIG.
- the absolute value of the potential gradient Ep between the cathode 25 constituting the plasma cathode 25a and the auxiliary electrode 41 is determined by the fact that the axial length of the dielectric cylinder 40 is equal to the first discharge path 20. Since the length (L a) of the a in the axial direction is set to ⁇ or less, and more preferably 3 or less, the potential gradient E a in the first cylindrical portion 21 a is twice or more the E a The absolute value of.
- each applied voltage (+ Vo, -Vt) is set in such a relationship.
- the pulsed main discharge occurs with the plasma cathode 25a serving as an electron supply source of the main discharge.
- the main discharge current flows between the cathode 25 and the anode 24.
- the operation mode of this embodiment will be further supplementarily described with reference to FIG.
- the voltage (+ V o) stored in the storage capacitor is supplied between the cathode and the anode. Then, a pulse-like trigger voltage (1 V t) that increases in the negative direction from a certain time t 1 is applied to the intermediate electrode, and at time t 2, dielectric breakdown of the discharge path occurs.
- a large main discharge current Id flows instantaneously between the anode and the cathode as shown in (b) of the figure.
- the main discharge current Id causes pulsed laser oscillation as shown in (c) of the figure, and a laser output having a narrow pulse width of, for example, about 5 nanoseconds (n-sec) is obtained.
- the voltage across the capacitor that is, the voltage between the anode and the cathode, drops instantaneously due to the main discharge, and after the end of the main discharge, rises again by charging the coaxial storage capacitor. This operation is repeated by applying a pulse trigger voltage corresponding to the repetition frequency of the pulsed laser oscillation.
- the output laser beam has a circular cross section and a uniform intensity distribution.
- the charge transfer is performed uniformly over the entire circumference and the impedance of the conduction path is reduced, so that a pulse laser oscillation with higher repetition can be achieved. It becomes possible.
- the impedance of the trigger voltage supply circuit to the intermediate electrode and the auxiliary electrode for the plasma cathode is extremely high, the main discharge current does not flow to the intermediate electrode and the auxiliary electrode, and the trigger voltage is applied. Since the current generated by the intermediate electrode and the auxiliary electrode is also very weak, there is no possibility that the materials of the intermediate electrode and the auxiliary electrode will cause spalling.
- the trigger voltage (Vt) applied to the intermediate electrode as in the above-mentioned embodiment. If the polarity of the voltage supplied from the storage capacitor to the cathode or anode is reversed, a high voltage is applied. It is practically desirable because it is not necessary to increase the withstand voltage performance of each part unnecessarily.
- the polarity of the trigger voltage (Vt) applied to the intermediate electrode and the voltage supplied to the cathode or anode from the storage capacitor should be the same, and the Each voltage may be set so that the potential gradients are equal or almost equal.
- each discharge path length and applied voltage are not limited thereto, and can be arbitrarily set as long as an operation similar to the above can be obtained.
- Figure 4 shows a graph as a guide.
- the horizontal axis represents the ratio of each discharge path length (Lb: La), and the vertical axis represents the ratio of each applied voltage and the potential gradient of each discharge path.
- Each of these applied voltage ratios and potential gradient ratios represents a value calculated as an absolute value.
- each discharge path length and each applied voltage can be appropriately set.
- the ratio (L b / L a) of each discharge path length suitable for practical use is generally about 1.5 to 4.0. of Range.
- the ratio of the applied voltages is such that the potential gradient ratio (S2 (Ea, or Eb) / Eo) is approximately 1.7 to 5.
- a range of 0 is appropriate.
- the ratio (E a / E b) of both potential gradients is 1.0 ⁇ 0 5, more preferably 1.0 ⁇ 0.3.
- thin conductor rings 3 1c and 3 2c is arranged so as to protrude with a plurality of conductor connection wires 31d and 32d.
- These thin conductor rings 31c and 32c may be arranged so as to overlap the outer peripheral positions of both ends of the intermediate electrode cylindrical part 26a as shown in the figure, or may be arranged in close proximity where they do not overlap. May be placed. Also, it may be provided only on one of the outer conductors.
- the intermediate electrode cylindrical portion 26a and each end portion 3 1b, 3 2b of each outer conductor are arranged so as to overlap by a predetermined distance m, n in the length direction.
- corona discharge and preionization accompanying the corona discharge occur more efficiently in the discharge path near the mutually overlapping region, and a good pulsed laser oscillation operation can be obtained.
- thin conductive rings 26 c and 26 d are respectively placed in the discharge tubes inside the first outer conductor end 31 b and the second outer conductor end 32 b. These are arranged, electrically connected to the cylindrical portion 26a of the intermediate electrode by, for example, three connection wires 26e and 26f, and mechanically supported.
- a high electric field is generated in the vicinity of the thin conductor rings 26a and 26b connected to the intermediate electrode 26 by the application of the trigger voltage, so that the corona discharge and the accompanying preliminary Ionization is more likely to occur.
- the embodiment shown in FIG. 8 has thin portions on the inner and outer sides of the discharge tube in the region between the cylindrical portion 26 a of the intermediate electrode and the first outer conductor end 31 b and the second outer conductor end 32 b.
- the outer conductor rings 31c and 32c and the thin inner conductor rings 26c and 26d are arranged to face each other. According to this embodiment, one layer is formed near the opposing inner and outer conductor rings. Since a high trigger electric field is generated, corona discharge and concomitant preionization are more likely to occur.
- FIG. 9 shows an embodiment in which an auxiliary electrode for generating a plasma cathode or a plasma anode is omitted, and a coaxial storage capacitor 3 is provided between the cathode 25 and the anode 24 from the first power supply device 27.
- This is a device that applies a main discharge voltage via 0, applies a trigger pulse voltage to the intermediate electrode 26, and performs a high repetition pulse laser oscillation operation.
- a cylindrical outer conductor is arranged around the electrode connecting the coaxial storage capacitor 30, that is, the outer periphery of the discharge tube on the anode side, and the main discharge path is
- the coaxial storage capacitor 30 is directly connected to the outer conductor end 32b located near the intermediate electrode 26 where pre-ionization is to be induced by
- a circular output laser beam with a uniform intensity distribution in the cross section was obtained.
- the storage capacitor 30 when the storage capacitor 30 is directly connected to the opposite end 32 a of the outer conductor or the electrode to which it is connected, that is, the anode 24 itself, as shown in FIG. It turned out to be a doughnut-shaped output laser beam with an intensity distribution with almost no laser light in the center.
- the coaxial storage capacitor 30 when the coaxial storage capacitor 30 is directly connected to the outer conductor end 32b extending close to the intermediate electrode 26 and short-circuited, a circular output laser having a uniform cross-sectional intensity distribution is obtained.
- the reason why a beam can be obtained is considered as follows. That is, the electric charge stored in the coaxial storage capacitor 30 is first transferred to the outer conductor end 32b located near the intermediate electrode, and pre-ionized to the discharge path regions B and A near this. As a result, the charges move from the outer conductor end 3 2b along the inner and outer surfaces of the outer conductor 32 at a speed substantially equivalent to the speed of light, and are guided to the anode 24, so that the electrons are stored inside the discharge tube. Field emission to cause dielectric breakdown of the main discharge path.
- uniform plasma is generated in the discharge tube along the discharge direction, and uniform plasma is generated in the discharge tube by pre-ionization due to the plasma and corona discharge near the intermediate electrode. This is considered to be due to discharge. If at least one of the cathode and the anode has a means for generating a plasma electrode, the generation of a uniform main discharge in the entire discharge path is further promoted.
- corona discharge occurs in the discharge path in the area between the end 32b of the second outer conductor surrounding the discharge tube due to dielectric breakdown of the discharge path and the end of the cylindrical part 26a of the intermediate electrode. Electrons are uniformly emitted into the discharge path by ionization and movement of the charge, and a uniform discharge is generated on a plane perpendicular to the discharge direction. For this reason, strong laser oscillation occurs even in the central portion of the discharge path in cross section, and a circular output laser beam having a uniform intensity distribution can be obtained. Such a laser beam is usually efficiently transmitted to a laser light utilization device through an optical fiber having a circular cross section.
- the first power supply device 27 and the second power supply device, that is, the trigger voltage power supply 28 are both AC power supplies.
- both AC power supplies have a phase difference of just or approximately 180 ° at a frequency corresponding to the repetition frequency of pulsed laser oscillation, and have the same peak voltage.
- a diode 35 is connected in series with the storage capacitor 30. According to this embodiment, as shown in (a) of the figure, a main discharge occurs at the phase 1 of the voltage at which each alternating voltage causes insulation breakdown in the discharge tube, and as shown in (b) of the figure. Thus, pulsed laser oscillation occurs.
- V o the voltage (V o) of the capacitor 30 is maintained at the peak value of the AC power supply voltage charged to the capacitor as indicated by the symbol V p, assuming that no main discharge occurs. However, by repeating the main discharge, that is, laser oscillation, the voltage decreases and rises repeatedly due to the main discharge as shown by the thick solid line in the figure.
- the main discharge voltage is DC charging
- dielectric breakdown in the discharge path will occur, the trigger voltage will decrease, and the laser output will decrease compared to AC driving, and the trigger voltage will vary in rising speed.
- laser oscillation may become unstable or cause jitter.However, when the AC drive is used as in this embodiment, the timing of dielectric breakdown is hardly shifted, and stable laser oscillation is maintained. You. Also, since the average voltage applied to each power supply element, capacitor, insulator part, etc. is smaller than in the case of DC, there is the advantage that the deterioration of each element is small and the reliability of the laser generator is improved. You.
- the embodiment shown in FIG. 13 is an apparatus that performs drive control using a single pulse power supply 50. That is, the output voltage is supplied to each electrode from the pulse power supply 50 via the pulse transformer 51.
- Symbol D a is a diode for storing a negative charge for main discharge in the storage capacitor 30, and D b and D c are for supplying a positive trigger pulse to the intermediate electrode 26 and the auxiliary electrode 41. Is the diode.
- the cathode 25 is shown on the right side in the figure, and the plasma anode 24 a composed of the anode 24, the auxiliary electrode 41 and the dielectric cylinder 40 is generated in the inner area on the left side in the figure, and operates. It is a configuration to do. That is, the main discharge current is supplied from the cations of the plasma anode 24a.
- the pulse power source 50 generates a negative pulse peak voltage having a predetermined repetition frequency.
- a waveform as shown in (a) of FIG. 14 appears. This changes rapidly between times t1, t2, and t3 on the time axis t.
- a positive pulse voltage appears and is applied as shown in (b) of FIG.
- a plasma anode 24a is generated in the inner region of the dielectric cylinder 40 sandwiched between the anode 24 and the auxiliary electrode 41, and the dielectric breakdown of the discharge paths on both sides is generated by the intermediate electrode 26.
- the cylindrical dielectric and the cylindrical dielectric are disposed near the cathode or anode, that is, in the vicinity of one of the first main electrode or the second main electrode, or in the vicinity of both main electrodes.
- An auxiliary electrode disposed adjacent to the cylindrical dielectric may be provided so that a plasma electrode is generated in an inner region of the cylindrical dielectric during operation.
- Plasma electrodes such as the plasma cathode and the plasma anode are generated as a result of the combined action of the creeping discharge and the creeping corona discharge inside the cylindrical dielectric. It is thought that there is.
- the embodiment shown in FIG. 15 is another example of a plasma electrode, that is, a plasma cathode, or a plasma anode. This is because the thin cylindrical portion at the center of the ceramic dielectric cylinder 40 is wrapped around the ring-shaped auxiliary electrode 41, and the outside thereof is further surrounded by a ceramic insulating cylinder and substantially inside.
- the auxiliary electrode 40 is embedded.
- a cathode 25 and a ring-shaped auxiliary cathode 25b are arranged at both ends of the dielectric cylinder 40, and these are formed by a conductor cylinder 25c arranged so as to cover the outer periphery of the dielectric cylinder 40.
- the cathode 25 and the ring-shaped auxiliary cathode 25a are electrically short-circuited.
- a pulse trigger power supply (not shown) is connected to the auxiliary electrode 41 via a high-resistance element 29b.
- a high voltage applied between the cathode 25 (or the anode 24) and the auxiliary electrode 41 causes a plasma electrode 25 to be applied to the inner surface of the dielectric cylinder 40 and the inner region thereof. a is generated. Further, the main discharge current is more reliably prevented from flowing into the auxiliary electrode 41, and the occurrence of sputtering is prevented.
- the dielectric cylinder 40 is divided into a plurality of, for example, two, and is provided side by side, and an auxiliary electrode 41 is arranged around a part of each of the dielectric cylinders 40. It is embedded inside. Then, a ring-shaped second auxiliary cathode 25 d is arranged between the adjacent dielectric cylinders 40, and together with the cathode 25 on both ends and the first auxiliary cathode 25 b, the conductor cylinder 25 c is used. Electrically short-circuited.
- Each auxiliary electrode 41 is connected to a pulse trigger power supply (not shown) via a high resistance element 29b. According to this embodiment, a plasma electrode is more easily generated on the inner surface and inner region of each dielectric cylinder 40.
- FIG. 17 is a pulse gas laser generator in which the intermediate electrode is omitted.
- reference numeral 21 denotes a single discharge tube
- 24 denotes an anode
- 25a denotes a plasma cathode
- Cp denotes a peaking capacitor
- L denotes an inductor
- S denotes a gap switch
- R denotes a protection resistor.
- the capacitor 30 is charged by the high-voltage power supply 27 via the resistor R and the inductor L while the switch S is off (open).
- gap switch S is turned on (closed)
- the charge on capacitor 30 peaks.
- capacitor Cp the plasma cathode 25a is generated inside the dielectric cylinder 40, and the dielectric breakdown of the discharge path leading to the anode 24 occurs, so that the laser medium is activated and laser oscillation occurs.
- the main discharge current flows between the auxiliary electrode 41 of the plasma cathode 25a and the anode 24.
- the source of the main discharge current is the plasma cathode, no bright spots or spattering from metal electrodes occur, and stable pulsed laser oscillation is maintained for a long time.
- a cylindrical outer conductor 32 is wound around the outer periphery of the discharge tube 21, and a coaxial peaking capacitor Cp is coaxially arranged.
- Inner electrode bonded to the inner periphery of cylindrical dielectric 30a of coaxial capacitor C p
- the storage capacitor 30 connected to the power supply 27 is electrically connected to the end 3 2 b of the cylindrical outer conductor 32 that extends to the vicinity of the cathode 25.
- the body ring 3 4 is directly mechanically and electrically connected all around.
- the outer peripheral electrode 30c bonded to the outer periphery of the cylindrical dielectric 30a is electrically connected to the cathode 25.
- the dielectric cylinder between the cathode 25 and the auxiliary electrode 41 is the dielectric cylinder between the cathode 25 and the auxiliary electrode 41
- Plasma cathode 25a is generated on the inner surface of 40 and its inner region, and the voltage across coaxial capacitor Cp is applied between cathode 25 and cylindrical outer conductor 32 to generate a plasma cathode 25a.
- the discharge path region B is pre-ionized, and a main discharge is induced.
- a pulsed laser beam having a circular cross section and a substantially uniform intensity distribution is output.
- the generation of bright spots and spattering caused by metal electrodes is suppressed, and stable operation is maintained for a long time.
- FIGS. 17 and 18 described above is an example in which laser oscillation is driven by a switch such as a gap switch.
- the laser oscillation is substantially performed without using a gap switch or the like.
- a power supply device including a high-voltage pulse or a trigger pulse generating circuit that performs the same operation may be replaced. As a result, a stable and long-life pulse gas laser generator can be obtained.
- the present invention is not limited to a configuration in which a plasma electrode is generated on one of the cathode and the anode, and is arranged in the vicinity of both the cathode and anode electrodes and in the vicinity of the cylindrical dielectric.
- Auxiliary electrode with A configuration may also be adopted in which a voltage is applied to the auxiliary electrode so that a plasma electrode is generated in the side region. This further suppresses the occurrence of bright spots and spattering on the metal electrode.
- this invention is a nitrogen (N 2) for generating a laser beam of ultraviolet region can not only applied to a laser or an excimer laser generator, can be widely applied to C 0 2 laser, other pulsed gas laser generator. Further, the present invention can be applied to a system in which a gas as a laser medium is circulated from the outside into the discharge tube. However, the present invention is particularly suitable for a type in which the discharge tube is sealed off as in the above-described embodiment. It has the advantage of being almost maintenance free.
- a pulse laser output having a circular cross section and a substantially uniform intensity distribution can be obtained with high repetition. Then, the occurrence of bright spots and spattering on the metal electrode is suppressed, and stable operation is maintained for a long time.
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Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99919644A EP0999619A4 (en) | 1998-05-20 | 1999-05-18 | PULSE GAS LASER DEVICE |
JP55280899A JP3808511B2 (ja) | 1998-05-20 | 1999-05-18 | パルスガスレーザ発生装置 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13809298 | 1998-05-20 | ||
JP10/138092 | 1998-05-20 |
Publications (1)
Publication Number | Publication Date |
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WO1999060676A1 true WO1999060676A1 (fr) | 1999-11-25 |
Family
ID=15213774
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1999/002584 WO1999060676A1 (fr) | 1998-05-20 | 1999-05-18 | Dispositif laser a gaz pulse |
Country Status (4)
Country | Link |
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EP (1) | EP0999619A4 (ja) |
JP (1) | JP3808511B2 (ja) |
CN (1) | CN1272232A (ja) |
WO (1) | WO1999060676A1 (ja) |
Families Citing this family (7)
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CN1324771C (zh) * | 2004-12-23 | 2007-07-04 | 中国科学院电子学研究所 | 横向激励二氧化碳激光器长脉冲泵浦装置 |
US9036765B2 (en) | 2006-05-30 | 2015-05-19 | Advanced Fusion Systems Llc | Method and system for inertial confinement fusion reactions |
KR101870467B1 (ko) * | 2010-10-29 | 2018-06-22 | 트럼프 인크. | Rf 여기식 레이저 조립체 |
JP6411120B2 (ja) * | 2014-08-04 | 2018-10-24 | 株式会社アマダミヤチ | レーザ装置 |
CN104953462A (zh) * | 2015-06-03 | 2015-09-30 | 张家港市旭华激光有限公司 | 一种激光发生器 |
CN105244749A (zh) * | 2015-11-11 | 2016-01-13 | 成都微深科技有限公司 | 一种具有等电位装置的二氧化碳激光器 |
RU2664780C1 (ru) * | 2017-11-10 | 2018-08-22 | Федеральное государственное бюджетное учреждение науки Институт сильноточной электроники Сибирского отделения Российской академии наук (ИСЭ СО РАН) | Азотный лазер, возбуждаемый продольным электрическим разрядом |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6424479A (en) * | 1987-07-20 | 1989-01-26 | Nec Corp | Discharge-excited pulsed gas laser device |
JPH01103889A (ja) * | 1987-06-05 | 1989-04-20 | Hitachi Ltd | ガスレ−ザ発生装置 |
JPH01282880A (ja) * | 1988-05-10 | 1989-11-14 | Toshiba Corp | レーザ発振装置 |
JPH05167157A (ja) * | 1991-12-11 | 1993-07-02 | Toshiba Corp | ガスレ−ザ装置 |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3931589A (en) * | 1974-03-21 | 1976-01-06 | The United States Of America As Represented By The Secretary Of The Navy | Perforated wall hollow-cathode ion laser |
JPS5818984A (ja) * | 1981-07-28 | 1983-02-03 | Nec Corp | レ−ザ装置 |
JPS58124283A (ja) * | 1982-01-20 | 1983-07-23 | Nec Corp | ガスレ−ザ装置 |
US4876693A (en) * | 1984-12-26 | 1989-10-24 | Hughes Aircraft Company | Integrated laser head and low inductance pulse forming circuit for pulsed gas lasers |
-
1999
- 1999-05-18 CN CN 99800772 patent/CN1272232A/zh active Pending
- 1999-05-18 EP EP99919644A patent/EP0999619A4/en not_active Withdrawn
- 1999-05-18 JP JP55280899A patent/JP3808511B2/ja not_active Expired - Fee Related
- 1999-05-18 WO PCT/JP1999/002584 patent/WO1999060676A1/ja not_active Application Discontinuation
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01103889A (ja) * | 1987-06-05 | 1989-04-20 | Hitachi Ltd | ガスレ−ザ発生装置 |
JPS6424479A (en) * | 1987-07-20 | 1989-01-26 | Nec Corp | Discharge-excited pulsed gas laser device |
JPH01282880A (ja) * | 1988-05-10 | 1989-11-14 | Toshiba Corp | レーザ発振装置 |
JPH05167157A (ja) * | 1991-12-11 | 1993-07-02 | Toshiba Corp | ガスレ−ザ装置 |
Non-Patent Citations (1)
Title |
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See also references of EP0999619A4 * |
Also Published As
Publication number | Publication date |
---|---|
JP3808511B2 (ja) | 2006-08-16 |
EP0999619A4 (en) | 2000-09-13 |
EP0999619A1 (en) | 2000-05-10 |
CN1272232A (zh) | 2000-11-01 |
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