JP2943923B1 - Excited oxygen-iodine laser generation method and apparatus - Google Patents

Abstract

A dry iodine laser generator is provided which is simpler. SOLUTION: A gas flow in which iodine, oxygen and a diluent gas are mixed is circulated through a circulation flow path 1 and high-frequency electric dischargers 2 and 5 apply an electromagnetic wave from a radio frequency to a microwave frequency to generate excited oxygen and iodine. To generate excited iodine, which is cooled through the supersonic nozzle 11 and guided to the laser resonator 3 to obtain an iodine laser. There is no need to replenish the gas mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new excited oxygen iodine laser generating method and a new excited oxygen iodine laser generating apparatus which do not rely on chemical excitation.

[0002]

2. Description of the Related Art An iodine laser emits excited iodine atoms (I ^*).
(2 P _1/2)) is the ground state from the excited state (I ⁽² P _3/2))
It uses the energy emitted when the energy is relaxed, and a high-power laser beam with a wavelength of 1.315 μm can be obtained. Thus, a highly efficient laser device can be configured. The industrial applications, to obtain a singlet excited oxygen molecules (O ₂ ⁽¹ Δ)) and the excitation iodine in a high yield by resonance energy ERROR reaction iodine atom _{^{(I * (2 P 1/2)}} ) An excited oxygen iodine laser capable of continuous laser oscillation utilizing the fact that it can be used is often used.

Conventionally, a chemically excited oxygen generation method has been used to obtain a singlet excited oxygen molecule which plays an important role in an excited oxygen iodine laser. The chemically excited oxygen generation method is a method in which a solution (BHP) of a mixture of an aqueous solution of hydrogen peroxide and an alkali solution such as potassium hydroxide is reacted with chlorine gas to obtain excited oxygen molecules. Term excited oxygen molecules can be generated.

[0004] The thus singlet excited oxygen molecules obtained ^{_{(O 2 (1 Δ))}} , molecular of which is conveyed by a carrier gas consisting of inert gas such as sublimation to helium or argon iodine vaporizer Mix with iodine. Then, the iodine molecule is dissociated and excited, and the excited iodine atom (I
^* ( ² P _1/2 )). The resulting light and excitation iodine that resonates between the resonator mirrors by feeding a gas flow to the laser oscillator _{^{(I * (2 P 1/2)}} ) are reacted with generating laser light amplified wavelength 1.315Myuemu. The pumped oxygen iodine laser thus obtained has a relatively high output and a good optical conductivity of a silica-based optical fiber, and can be used industrially.

However, the chemically excited oxygen generation method requires an expensive raw material, and because it is a wet type, a water removal device for removing water that deactivates excited iodine, a waste liquid exhaust gas treatment device for collecting by-product harmful substances, or a raw material. It is necessary to equip a regenerator, and there has been a problem that equipment costs and operating costs are increased.
As means for avoiding the problem of the chemically excited oxygen generation method, for example, JP-A-7-254 filed by the present applicant
There is known a method using a discharge-type excited oxygen generation method for obtaining excited oxygen by RF discharge, as disclosed in JP-A-738 and JP-A-9-186377.

[0006] The invention disclosed in Japanese Patent Application Laid-Open No. 7-254738 discloses that when a hollow cathode having a specific shape is passed through oxygen having an appropriate flow rate and pressure to perform RF discharge,
This is based on the efficient generation of excited oxygen in the after-glove plasma layer formed in the hollow cathode portion. As shown in FIG. 6, an iodine gasified by an iodine vaporizer is injected into a flow of singlet excited oxygen efficiently generated by an RF discharge type excited oxygen generator to transfer energy to generate excited iodine atoms. Then, an iodine laser is obtained by causing a laser oscillator to react and release energy. After the energy release, the gas stream is passed through a vacuum pump after capturing and separating reusable substances such as iodine molecules with recombined iodine atoms and harmful substances that must not flow out using an iodine trap or other recovery device. Released into the atmosphere.

The invention disclosed in Japanese Patent Application Laid-Open No. 9-186377 discloses a method for reducing the flow of the dissociated iodine atoms in order to improve the oscillation efficiency by reducing the amount of the excited oxygen molecules wasted in dissociating the iodine molecules. It is designed to be injected into an excited oxygen stream. When high-frequency power is applied using the injector hole that injects the iodine flow into the excited oxygen flow as a hollow cathode, a fountain-like plasma is generated at the periphery of the injector hole, and the iodine molecules passing through the plasma are dissociated into atoms. Since it is mixed with the excited oxygen flow, the proportion of the excited oxygen molecules wasted due to the dissociation of the iodine molecules is reduced, so that a higher-output iodine laser can be generated.

The discharge-type excited oxygen iodine laser generation method compensates for the drawbacks of the chemically excited oxygen generation method, and makes it possible to obtain a more economical and highly practical iodine laser. However, even with these methods, the mixing of iodine and oxygen is imperfect, so that a loss occurs when the excited oxygen energy transfers to the iodine atom, and the excited oxygen generated by the excited oxygen generator is mixed with iodine. During the transfer to the part, the excited oxygen is inactivated and energy loss occurs. Also, in the conventional discharge-excited oxygen-iodine laser device, the atomic temperature is increased by high-frequency discharge,
When large thermal energy excites atoms or molecules, an excited state that does not contribute to laser generation or a harmful excited state that inhibits laser generation also appears, so that the efficiency of iodine laser generation is limited.

Therefore, in order to meet various industrial requirements, it is necessary to devise a device for further increasing the output level. Further, it is preferable to reduce equipment costs and operation costs as much as possible. In order to improve the efficiency of laser generation, it is preferable that the energy transfer reaction between excited oxygen molecules and iodine atoms be actively performed at the position of the laser resonator that requires the excited iodine atoms. The present inventors have intensively studied a method for generating an iodine laser having a high laser generation efficiency. An inexpensive iodine laser generator capable of withstanding the temperature was obtained.

[0010]

An object of the present invention is to generate excited oxygen molecules without using a chemically excited oxygen generation method and to generate excited iodine atoms by an energy transfer reaction from the excited oxygen molecules. To provide an excited oxygen iodine laser generating method and apparatus for obtaining laser light with high efficiency. Another object of the present invention is to provide an iodine laser generator which prevents loss of raw materials, has high safety and is inexpensive, and has a low operating cost.

[0011]

In order to solve the above-mentioned problems, a method for generating an excited oxygen-iodine laser according to the present invention restricts the flow of a mixed gas containing iodine molecules, oxygen gas and diluent gas.
A high-frequency electromagnetic wave in the radio or microwave range is applied to generate excited oxygen molecules.
Is provided immediately after the throttle while the gas mixture containing
The excited oxygen molecules reach the laser cavity and cause an energy transfer reaction with the dissociated iodine atoms to generate excited iodine atoms. The excited iodine atoms are provided immediately after the diaphragm . And emits laser light by emitting energy.

In the present invention, iodine atoms dissociated by exciting oxygen molecules and dissociating the iodine molecules by irradiating high frequency electromagnetic waves in the radio wave or microwave range to a mixed gas containing iodine molecules, oxygen gas and diluent gas. Activate.
Scheme of the present invention has no deactivation of excited iodine atoms by because water fraction cried in a wet, also high at that focus mixed gas stream
Gas heating time is shortened by applying high frequency electromagnetic waves.
Temperature rise and expands and cools after passing through the throttle.
It is difficult to deactivate excited oxygen molecules.
Excited iodine atoms can be generated with high energy efficiency at the provided resonator position . High-output laser light can be generated by applying the resonance light of the laser resonator to the excited iodine atoms thus obtained. Radio waves or microwaves may be selected mainly for exciting oxygen molecules, but may also be used for dissociation of iodine molecules to improve the utilization efficiency of excited oxygen molecules. Note that microwaves are more efficient for exciting oxygen molecules.

Further, since a mixed gas flow containing iodine and oxygen is used, iodine atoms are present at positions where oxygen molecules are excited. Therefore, as in the prior art, when the excited oxygen gas is transported to a position where it is mixed with iodine gas. The iodine atom can be efficiently excited without deactivation. In addition, since iodine and oxygen are homogeneously mixed at a position where a high-frequency electromagnetic wave is applied, there is no transfer loss of excitation energy due to a shortage of iodine atoms around excited oxygen. Note that when activated oxygen molecules activated by high-frequency electromagnetic waves are mixed with activated iodine activated by high-frequency electromagnetic waves, the yield of excited iodine atoms is significantly improved as compared with the case where iodine is mixed with activated oxygen molecules. Therefore, by applying high-frequency electromagnetic waves to a mixed gas flow containing iodine and oxygen, a mixture of activated oxygen molecules and activated iodine molecules can be directly obtained, and the iodine laser extraction efficiency is improved.

In the method for generating an excited oxygen / iodine laser according to the present invention, the mixed gas flow to which the electromagnetic wave is applied may be cooled to a supersonic flow. Further, it is preferable to use helium as a diluent gas because the stabilization of discharge and the cooling effect due to supersonic speed are increased. Note that the dissociation of iodine and the excitation of oxygen may be performed using both radio waves and microwaves. Further, the mixed gas may be circulated and used.

When the mixed gas flow is made to be a supersonic flow, the temperature of the mixed gas flow decreases due to a remarkable cooling effect (Joult-Thomson effect) by adiabatic expansion. Then, the equilibrium constant of the reaction formula for transferring energy from excited oxygen molecules to iodine atoms increases, and the amount of excited iodine atoms generated increases, thereby improving laser extraction efficiency. Also, the saturation intensity of the iodine laser is inversely proportional to the time that the gas flow crosses the beam in the laser oscillation section and is proportional to the number of times of pumping with excited oxygen during this time.
While the time during which the gas flow traverses the beam is shortened, the gas flow traverses the beam while the ratio of excited oxygen molecules is high, so that the saturation intensity of the laser increases and a high-power laser can be obtained.

When helium is used as a diluent gas, the specific heat ratio is small, the heat capacity of the mixed gas is small, so that the cooling efficiency by supersonic speed is improved, and since the discharge efficiency is large, the yield of excited oxygen is increased. In addition, for example,
If the roles are divided so that iodine is mainly dissociated by radio waves and oxygen is mainly excited by microwaves, the timing of both can be adjusted appropriately, and the position of the laser oscillator that amplifies the laser with the excited iodine atoms An energy transfer reaction between the iodine atom in the ground state and the excited oxygen can be caused. In particular, it is preferable to apply an RF wave that dissociates iodine molecules upstream of the microwave discharge device in anticipation of the time until the dissociated iodine atoms recombine.

After the mixed fluid has passed through the laser resonator, the iodine atoms are recombined to form iodine molecules, and the excited oxygen is deactivated to form oxygen molecules in the ground state. There is no change from the mixed fluid supplied to the discharger. Therefore, if the pressure is increased to the degree of vacuum at the gas supply position of the high-frequency discharger and forced circulation is performed, it can be reused as it is, and it is not necessary to release harmful substances to the outside and replenish expensive materials. . Of course,
Needless to say, the actual apparatus should be provided with a replenishing device so as to be able to cope with the initial replenishment and the situation requiring special replenishment.

Since iodine may adhere to the inner wall of a circulation duct or the like and its concentration may decrease, it is preferable to adopt a method of providing a heating mechanism in the circulation system and performing appropriate heating to prevent solidification. Further, a system that constantly measures the fluid temperature and controls the heat exchanger may be attached. Alternatively, a heater may be provided in a pipe portion to which iodine is fixed to prevent the fixation or to sublimate the fixed solid iodine.

Furthermore, the excited oxygen iodine laser generator of the present invention includes a high-frequency discharger provided with a gas supply path and a laser resonator provided with a pair of resonance mirrors. And
The high-frequency discharger applies radio waves or microwaves to the flow of the mixed gas containing iodine molecules, oxygen gas, and diluent gas flowing from the gas supply path to generate excited oxygen molecules, and the laser resonator resonates. A mixed gas flow containing excited oxygen molecules and dissociated iodine atoms is introduced between the mirrors, and the generated excited iodine atoms are stimulated to generate an iodine laser.

In the iodine laser generator according to the present invention, the mixed gas containing iodine molecules, oxygen gas and diluent gas is irradiated with an electromagnetic wave in a radio or microwave range by a high frequency discharger to excite the oxygen molecules to dissociate the iodine molecules. Activate the dissociated iodine atoms. Radio waves or microwaves can be used not only to excite oxygen molecules but also to dissociate iodine molecules, thereby improving the utilization efficiency of excited oxygen molecules. In the present invention, since the oxygen molecules are completely mixed with the iodine gas in the high-frequency discharger in which the oxygen molecules are excited, the energy transfer loss due to the deactivation of the excited oxygen due to the transfer and the shortage of the iodine atoms is small, and the iodine atoms are efficiently removed. Can be excited.

In the iodine laser generator of the present invention,
A second high-frequency discharger may be provided upstream of the first high-frequency discharger. For example, when the iodine molecules are dissociated in the upstream second high-frequency discharger and the oxygen molecules are excited in the downstream first high-frequency discharger, the ratio of the excited oxygen consumed for the dissociation of the iodine molecules is reduced and the efficiency is improved. An iodine laser can be generated.

Further, it is preferable to provide a supersonic nozzle in the portion of the first high-frequency discharger for passing the mixed gas flow to produce a supersonic flow. Further, it is preferable to provide a laser resonator at a portion downstream of the supersonic nozzle where the mixed gas flow becomes supersonic. When a supersonic nozzle is used, a mixed gas flow containing a large amount of excited oxygen molecules in response to an electromagnetic wave passes through the supersonic nozzle, and the temperature decreases due to the Joule-Thomson effect, and the equilibrium constant increases in the direction of promoting the reaction. Change, the energy transfer reaction takes place actively, and the excited iodine atom increases,
Since the number of pumps in the laser resonator is increased, the laser extraction efficiency is improved.

When oxygen molecules are discharged and excited upstream of the supersonic nozzle, the pressure is high and the excited oxygen is largely deactivated. On the other hand, when the discharge is excited downstream of the supersonic nozzle, the cooling effect of the adiabatic expansion accompanying the supersonic speed is offset by the discharge heating. Therefore, pinpoint discharge excitation in the throat portion, which is a transition region from subsonic to supersonic, is preferable. In addition, since the flow rate of the gas mixture is increased by the supersonic nozzle, the time required to traverse the beam is reduced, and a high-power laser can be obtained. Furthermore, when a laser resonator is arranged in the supersonic portion, the mixed gas flow is at a low temperature, so that it is easy to re-excit the iodine atoms that have fallen to the ground state by pumping. Oscillation efficiency increases.

The discharge may be performed by disposing at least one pair of electrodes outside or inside the gas supply path of the high-frequency discharger. Further, a circulation path of the mixed gas flow may be formed, and a vacuum pressure increasing device such as a vacuum pump may be provided on the way to return the mixed gas flow flowing out of the laser resonator to the gas supply path of the high-frequency discharger for forced circulation. Good. When the mixed gas flow is circulated, it is preferable to provide a temperature detecting end and a heating mechanism to control the temperature so that iodine molecules do not adhere to the wall of the circulation path. Although an independent heat exchanger may be provided in the circulation path, it goes without saying that a heater may be added to the circulation path itself to form a heater.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the excited oxygen iodine laser generator of the present invention, FIG. 2 is a perspective view showing the configuration of this embodiment, and FIG. 3 is a supersonic diaphragm of a high-frequency discharger used in this embodiment. A sectional view showing the
4 is a cross-sectional view taken along the plane IV-IV in FIG.
FIG. 7 is an emission spectrum diagram for explaining the operation principle in the present embodiment.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The excited oxygen iodine laser generator of the present embodiment is a discharge-excited oxygen iodine laser device of a forced circulation type. As shown in FIGS. 1 and 2, the laser generator includes a flow path 1 through which gas circulates. A first high-frequency discharger 2 that irradiates microwaves to a flowing gas in a circulation flow path 1
A laser resonator 3 having a pair of resonator mirrors is provided downstream of the first high-frequency discharger 2. A vacuum blower 4 is provided downstream of the laser resonator 3, and an outlet of the vacuum blower 4 is connected to a pipe inlet of the first high-frequency discharger 2 to form a circulation path. A throttle 1 serving as a supersonic nozzle is provided in a pipe flowing into the first high-frequency discharger 2.
A second high-frequency discharger 5 for discharging electromagnetic waves (RF waves) of a radio frequency is provided upstream of the diaphragm 11. The circulation path 1 is provided with a heat exchanger 6 and a temperature measurement control device 7 having a temperature detecting end.

In the circulation channel 1, a mixed gas containing iodine gas (I ₂ ), oxygen gas (O ₂ ) and diluent gas is circulated. As the diluent gas, an inert gas (IG) such as helium, argon, or nitrogen gas is used. In particular, helium is preferable for discharge efficiency and stabilization and temperature control by forming a supersonic flow. The mixed gas dissociates iodine molecules contained in the mixed gas into iodine atoms by applying an electromagnetic wave of about 100 MHz in the second high-frequency discharger 5 provided upstream of the supersonic nozzle 11, and the supersonic nozzle 11 Supply. The second high-frequency discharger 5 may be configured by providing an electrode for each pipe branching to a plurality of supersonic nozzles 11, but performs iodine atom dissociation before branching using an electrode that covers the entire circulation path 1. It may be configured as follows.

The electrodes of the second high-frequency discharger 5 may be provided outside the pipe of the circulation flow path 1 or inside thereof. When an electrode is provided outside the pipe, a part of the pipe is formed of a material that transmits electromagnetic waves, such as glass, ceramic, or plastic, and a pair of electrodes facing each other is provided outside the pipe. In such a structure, since the electrode does not come into direct contact with chemically reactive iodine, the material of the electrode can be freely selected, and the shape and area of the electrode can be selected for high-frequency discharge or microwave discharge according to the shape of the pipe. An appropriate one can be selected. For example, the plate electrodes can be arranged so as to face each other with a rectangular cross section vertically interposed therebetween.

The electrodes of the second high-frequency discharger 5 may be provided inside the piping of the circulation channel 1. When the electrode is installed inside the pipe, the corrosiveness of iodine must be taken into consideration, but since it acts directly on the gas containing iodine molecules without intervening insulating material, it can be effectively dissociated to the atomic state with low power. it can. Further, the dissociation efficiency can be improved by shortening the distance between the electrodes. Furthermore, since the pipe does not need to be an insulator, there is an advantage that the material of the pipe such as stainless steel having conductivity can be freely selected.

The mixed gas in the circulation channel 1 is
The supersonic flow is generated downstream of the throttle 11 by maintaining a vacuum of several tens Torr to several hundred Torr upstream of 1 and a vacuum of several Torr to several tens Torr downstream. The pressure relationship across the throttle 11 is maintained by the vacuum blower 4 interposed in the circulation path 1. As the vacuum blower 4, various types such as a positive displacement or turbo type vacuum pump and a roots pump can be used, but it is necessary that the vacuum blower 4 does not affect the mixed gas component used for circulation.

The mixed gas containing iodine which has been dissociated into an atomic state by the action of the second high-frequency discharger 5 is sucked into the vacuum blower 4, and the supersonic diaphragm 11 is turned on before the iodine atoms return to the molecular state.
Flows into. The supersonic throttle 11 makes the gas flow sonic at the bottleneck part by passing the gas flow supplied from the upstream through the bottleneck and sucking it with high vacuum from the downstream, and the gas stream is fed to the gradually widened downstream channel. The supersonic region is generated in the downstream portion of the bottleneck by guiding.

The first high-frequency discharger 2 provided at the position of the supersonic throttle 11 applies microwaves to the mixed gas passing through the throttle 11 to generate mainly excited oxygen. FIG. 5 is a measurement example showing that a mixture of activated iodine and excited oxygen produces excited iodine atoms with high efficiency. The horizontal axis in the figure is the wavelength (μm) of the emission spectrum, and the vertical axis is the radiation intensity expressed in arbitrary units. The spectral distribution curve indicated by 1 in the figure is the emission spectrum of excited oxygen, which is 1.27 μm specific to excited oxygen.
There is a peak at the position. The distribution curve indicated by 2 is a case where iodine gas is injected into the excited oxygen gas, and a peak at 1.315 μm indicating the presence of the excited iodine atom appears.
The spectrum distribution curve indicated by 3 in the figure is a measurement result when a mixed gas of oxygen and iodine was excited by microwaves, and it can be seen that an extremely large amount of excited iodine atoms was generated as compared with the case of 2.

Since the mixed gas contains activated iodine, excited oxygen acts on the mixed gas to generate excited iodine atoms with high efficiency, thereby easily forming a population inversion necessary for laser resonance. As described above, the excited oxygen-iodine laser generator of the present embodiment mixes excited oxygen and activated iodine by applying high-frequency electromagnetic waves to a mixed gas containing oxygen and iodine, thereby promoting a reaction between the two to enhance the reaction. It is designed to generate a concentration of excited iodine atoms. Further, since the mixed gas containing oxygen and iodine is completely homogeneously mixed while circulating in the circulation channel 1, iodine atoms are always present around the excited oxygen molecules, and energy transfer loss does not occur.

As shown in FIG. 3, the first high-frequency discharger 2 is, for example, 2.4 GH guided from a magnetron 21.
The microwave of z is configured to be reflected by the reflection plate 22 to form a standing wave in the waveguide 23. The circulation flow path 1 forms a bottleneck that becomes the supersonic stop 11 at substantially the center of the waveguide 23. In the mixed gas flow path 1, a portion of the supersonic diaphragm 11 penetrating the first high-frequency discharger 2 is made of a glass tube that transmits electromagnetic waves, and is embedded in cones 24 and 25 protruding from both walls of the waveguide 23. Have been. The circulation flow path 1 through which the mixed gas flows narrows conically in the upstream cone 24, and after forming a bottleneck, widens again in the downstream cone 25. The narrowest narrow portion of the supersonic diaphragm 11 is the cone 2
In the portion where the tips of 4 and 25 abut each other with a slight gap therebetween, for example, a portion having a length of 1 mm is exposed in the waveguide 23. Such a conical butting structure has an effect that the microwave generated in the high-frequency discharger 2 is concentrated on the supersonic throttle 11 and efficiently acts on the mixed fluid therein.

The circulation flow path 1 penetrating the first high-frequency discharger 2 has a plurality of parallel flow paths adapted to the amount of circulation, and a supersonic throttle 11 is provided for each branch flow path. As shown in FIG. 4, each supersonic diaphragm 11 is provided with a first waveguide 23 having a magnetron 21 and a reflection plate 22, and these supersonic diaphragms 11 are arranged in a straight line. And a second waveguide provided in a direction perpendicular to the first waveguide 23.
The second waveguide 28 having the magnetron 26 and the second reflector 27 is disposed so as to cover all the apertures 11, and a large electromagnetic wave energy is concentrated on the gas mixture in the supersonic aperture 11. I can do it.

The laser resonator 3 includes a resonator mirror that totally reflects laser light and a take-out mirror that can take out a part of the light, that is, a resonator mirror for output.
The light is amplified by interacting with the excited iodine atoms in the gas body that crosses the beam while reciprocating between the mirrors, and the laser light with the desired intensity is extracted. The light exits from the mirror. The iodine atom that has fallen to the ground state due to this pumping action returns to the excited state due to energy transfer from excited oxygen molecules, and can again contribute to the pumping action. The excited oxygen molecule transfers energy to return to the ground state oxygen molecule. When the ratio between the excited state oxygen and the ground state oxygen falls below the threshold, laser oscillation cannot be performed.

The laser resonator 3 is disposed in the supersonic region downstream of the supersonic diaphragm 11 so that resonating laser light passes through the discharge portions of all the supersonic diaphragms. In a place where a supersonic flow is formed, the fluid is cooled due to adiabatic expansion, and the temperature becomes extremely low, for example, about 150K depending on conditions. It has been observed that when helium is used as the diluent gas, the heat capacity is reduced and the cooling effect is large. For example, it has been observed that the oscillation efficiency is increased by about 10% as compared with the case where argon is used as the diluent gas. Where ² P _1/2 − ^{2 of the} iodine atom
To create a population inversion for enabling laser oscillation between P _3/2 state, oxygen molecules of the electron excited state (O ₂ ⁽¹ Δ)) must be such that there are more than an oscillation threshold.

It is to be noted that iodine in an atomic state formed by dissociating iodine molecules by high-frequency discharge is less likely to recombine than iodine atoms dissociated by heat, and when there is no deactivating factor such as moisture, for example, 70 cm is transported in a pipe. After that, the atomic state is maintained at a high rate. Accordingly, iodine atoms are always supplied to the position of the laser resonator 3, and excited iodine atoms can be obtained by a resonance energy transfer reaction with excited oxygen molecules.

[0039] Scheme O ₂ excited oxygen and iodine atom ^{(1 Δ) + I (2} P 3/2) ← → O 2 (3 Σ) + equilibrium constant at I ^{* (2} P _1/2) is a function of temperature Considering the degeneracy of the iodine atomic energy level due to the hyperfine structure, the oscillation threshold of the oxygen excitation rate is [O ₂ ^* ] / [O ₂ ] = 1.33exp (−403 / T) ·
([I ^* ] / [I]). Here, [I ^* ] / [I]> 0.5. ^{_{Further, (O 2 (3 Σ)}} ) is the ground state oxygen molecules, I ⁽² P
_3/2) is an iodine atom in the ground state, I ^{* (2} P _1/2) is an iodine atom in the excited state. Here, T is the reaction temperature.

The reaction at room temperature (T = 300K) requires an oxygen excitation rate of 17% or more, whereas the reaction at T = 150K using supersonic flow results in an oxygen excitation rate of 5%.
It can be seen that laser oscillation is possible even to the extent. As described above, disposing the laser resonator 3 in the supersonic region downstream of the supersonic diaphragm 11 and lowering the temperature of the mixed fluid in a place where the energy transfer reaction is performed is remarkable in improving the laser extraction efficiency. It has a great effect.

In order to obtain a high output beam, it is preferable to increase the saturation intensity of the laser and use an extraction mirror having a high transmittance. In order to be able to use a mirror having a high transmittance, the amplification factor must be increased. The saturation intensity Is (W / cm ² ) of the laser
Is represented by Is = (hν / ρ) · (2n / τ). Here, hν is energy per one iodine laser photon (Joule), ρ is stimulated emission cross section of iodine atom (cm ² ), and n is pumped by excited oxygen while iodine atom crosses the beam of the resonator. Average number, τ
Is the time (sec) that the gas flow traverses the resonator beam. Therefore, to increase the saturation intensity of the laser,
It is preferred to use supersonic flow to increase the velocity of the fluid passing through the laser resonator and reduce the time τ across the beam.

The mixed gas containing iodine gas (I ₂ ), oxygen gas (O ₂ ) and inert gas (IG) circulating in the circulation channel 1 is not consumed by the generation of the iodine laser. Oxygen molecules excited by the discharge return to oxygen molecules in a ground state due to energy transfer and deactivation, and dissociated iodine molecules also return to the original state by binding in circulation. Of course, the inert gas does not change during circulation. Therefore,
If the circulation channel 1 can be completely sealed, there is no need to replenish the source gas at all. In this way, since there is no need to artificially regenerate or replenish the raw materials and circulate the mixed gas to convert the electric energy into light energy, the running cost can be significantly reduced in principle.

However, since iodine may solidify at a low temperature and adhere to the wall of the circulation path, in order to maintain the gaseous state, maintain the gas temperature at or above a predetermined value or heat the piping so that the iodine does not adhere. There is a need to. For this reason, the temperature of the gas in the circulation path 1 is measured at the temperature detecting end, and the output of the heat exchanger 6 is controlled by the temperature controller 7. If the heat exchanger 6 is disposed on the discharge side of the vacuum pump 4 where the degree of vacuum becomes lower, the heat exchange efficiency can be further increased. The set temperature of the temperature controller 7 is set to a value at which iodine does not solidify in a mixed gas environment.

It is also possible to form a portion where iodine easily adheres at a predetermined position in the circulation path and treat the solid iodine deposited there as an iodine gas supply source. In the present embodiment, a high-frequency electromagnetic wave is applied to the mixed gas flow of iodine, oxygen, and an inert gas, and the temperature in the laser resonator is reduced by using a supersonic nozzle to increase the passage speed. In addition, a sealed flow path through which the mixed gas is circulated is formed so as to perform forced circulation. However, even if these requirements are not all provided, it goes without saying that each of them exhibits a predetermined effect. .

In this embodiment, the radio frequency and the wavelength of the microwave have been specifically described for the purpose of explanation. However, it is also possible to apply high-frequency electromagnetic waves in frequency ranges different from those described above to excited oxygen molecules and iodine dissociation. It is possible. Further, since the action of these high-frequency electromagnetic waves has low frequency dependence, various wavelengths other than the described values can be selected. Although not shown in the figure, the circulation path 1 may be provided with a gas inlet for initial filling or replenishment of the mixed gas.

[0046]

As described above, the discharge-excited oxygen-iodine laser generator of the present invention excites a mixed gas of oxygen molecules, iodine molecules and a diluent gas by high-frequency discharge without using a wet chemically excited oxygen generator. Since the excited iodine atom is obtained by activation, the excitation energy is hardly deactivated and the energy loss due to insufficient mixing is small, so that a high-output iodine laser with high laser light extraction efficiency can be obtained. In addition, since the iodine laser generator is sealed and the medium gas is forcibly circulated and used, the replenishment of raw materials is minimized, and processing equipment required for collecting raw materials and discharging harmful substances is not required. Operation costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of an excited oxygen iodine laser generator of the present invention.

FIG. 2 is a perspective view illustrating the configuration of the present embodiment.

FIG. 3 is a cross-sectional view showing a supersonic throttle portion of the high-frequency discharger used in the present embodiment.

FIG. 4 is a sectional view taken along a plane IV-IV in FIG. 3;

FIG. 5 is an emission spectrum diagram for explaining the operation principle in the present embodiment.

FIG. 6 is a block diagram showing an example of a conventional excited oxygen iodine laser generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circulation flow path 11 Supersonic throttle 2 First high frequency discharger 21, 26 Magnetron 22, 27 Reflector 23, 28 Waveguide 24, 25 Conical body 3 Laser resonator 4 Vacuum blower 5 Second high frequency discharger 6 Heat exchange 7 Temperature control device

Continuation of the front page (72) Inventor Taro Uchiyama 2663-9 Naruse, Machida-shi, Tokyo (56) Reference JP-A-7-254738 (JP, A) JP-A 9-186377 (JP, A) (58) Survey Field (Int.Cl. ⁶ , DB name) H01S 3/095

Claims (13)

(57) [Claims] 1. A mixed gas containing iodine molecules, oxygen gas, and a diluent gas is generated, and a flow of the mixed gas is guided to a restrictor.
At the aperture position, an electromagnetic wave in the radio or microwave range is applied to generate excited oxygen molecules, and a mixture containing the excited oxygen molecules is generated.
The mixed gas passes through the throttle and cools immediately after the throttle.
Reaches the laser resonator provided later, to generate excited iodine atoms undergo iodine atom and energy ERROR response excitation oxygen molecules are dissociated, the laser beam excitation iodine atom release energy in said laser resonator Generating an excited oxygen iodine laser. 2. The method for generating an excited oxygen-iodine laser according to claim 1, wherein the mixed gas stream to which the electromagnetic wave is applied is cooled to a supersonic flow. 3. The method for generating an excited oxygen iodine laser according to claim 1, wherein helium is used as a diluent gas for said mixed gas flow. 4. The excited oxygen-iodine laser according to claim 1, wherein a radio wave is applied to dissociate iodine and a microwave is applied to excite oxygen molecules. How it occurs. 5. The method for generating an excited oxygen iodine laser according to claim 1, wherein the mixed gas is circulated. 6. A the gas supply passage and a gas supply channel for flowing a gas mixture comprising molecular iodine and oxygen gas and a diluent gas
A high-frequency discharger for generating excited oxygen molecules by applying a radio wave or a microwave in the flow of the gas mixture to the flow of the gas mixture with the throttle; and a pair of resonant mirrors immediately downstream of the throttle. An excited oxygen / iodine laser provided with a laser resonator for generating an iodine laser by introducing a mixed gas flow containing the excited oxygen molecules and dissociated iodine atoms between the resonant mirrors and releasing energy to the generated excited iodine atoms Generator. 7. The apparatus according to claim 6, further comprising a second high-frequency discharger provided upstream of said first high-frequency discharger.
The excited oxygen iodine laser generator according to the above. 8. excited oxygen iodine laser generator according to claim 6 or 7, wherein said diaphragm is a supersonic nozzle to supersonic flow by passing said mixed gas stream. 9. The excited oxygen iodine laser generator according to claim 8, wherein the laser resonator is provided in a portion where the mixed gas flow has a supersonic speed. 10. The apparatus according to claim 1, wherein said second high-frequency discharger is above said throttle.
Excited oxygen iodine laser generator according to claim 6, wherein 9 to be those comprising at least one pair of electrodes disposed outside of the gas supply passage in the flow. 11. The apparatus according to claim 11, wherein said second high-frequency discharger is above said throttle.
Excited oxygen iodine laser generator according to claim 6, wherein 9 to be those comprising at least one pair of electrodes disposed within the gas supply passage in the flow. 12. A vacuum pressurizing device for inflowing a mixed gas flow flowing out of the laser resonator and supplying the mixed gas flow to a gas supply path of the high-frequency discharger so as to forcibly circulate the mixed gas flow. 7. The method according to claim 6, wherein
12. The excited oxygen iodine laser generator according to any one of items 1 to 11. 13. A circulation path for circulating the mixed gas flow, comprising a temperature detecting end, a heat exchanger, and a temperature controller, so that iodine molecules in the mixed gas flow are not coagulated and the oscillation efficiency is increased due to excessive temperature rise. 13. The excited oxygen iodine laser generator according to claim 12 , wherein the temperature is controlled so that the temperature does not decrease.