JPH05137966A - Vapor photochemical reaction device using laser beam - Google Patents

Abstract

PURPOSE:To greatly improve the photochemical reaction efficiency per laser power and to provide a reaction stage of a low cost by effectively utilizing all of the laser powers which can be taken out of a laser medium in laser photochemical reaction. CONSTITUTION:This laser photochemical reaction device is provided with telescopes and a total reflection mirror M3 on the outer side of a partial reflection mirror M2 constituting laser resonators together with a total reflection mirror M1. A reaction vessel 2 is installed between the telescopes and the focal lengths and spacings of the telescopes are so controlled that the space mode profiles in the three resonators M1-M2, M2-M3, M1-M3 are respectively aligned, by which the laser beam is multiple-reflected without having a diffraction loss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reaction apparatus for performing a photochemical reaction such as isotope separation using a laser beam, and in particular, most of laser energy that can be extracted from a laser medium is effectively used for the photochemical reaction. The present invention relates to a gas phase photochemical reaction device.

[0002]

2. Description of the Related Art In recent years, the increase in output power and the diversification of oscillation wavelength in laser technology have promoted research into utilizing laser for photochemical reactions. The most typical example of the application of laser to photochemical reaction is isotope separation / enrichment technology of various elements from hydrogen to uranium. This is because the chemical reaction of only the substance containing the isotope of is promoted. Various methods and devices have been proposed for the isotope separation / concentration reaction using a laser beam. For example, in the one disclosed in FIG. 1 of JP-A-60-132,629, pulsed carbon dioxide laser light is condensed by a long focus lens and introduced into a reactor, and photochemistry is performed in the vicinity of the focal plane. The reaction is carried out. In such a photochemical reaction using infrared multiphoton absorption, generally, the energy density of the laser increases exponentially with the increase of the energy density up to a certain value, and beyond that, the so-called critical efficiency is saturated. Fluence exists. For this reason, the laser beam is converged by a condensing lens having a focal length such that a critical fluence can be obtained at the condensing position, and the reaction proceeds near the focal point. Therefore, in such a reactor, the laser power is effectively used only in a part of the reactor, and in the region where the critical fluence is less than the inside of the reactor, the laser energy is absorbed without contributing to the reaction. Since the remaining energy is dissipated from the exit end of the reactor, there is a problem that only a few percent to 20% of the laser power actually output from the laser oscillator can be effectively used for the chemical reaction.

In the photochemical reaction process using a laser beam, the ratio of the laser is the highest in both the initial cost and the running cost, and in order to realize the low cost laser photochemical reaction process, the laser power Effective utilization technology is an essential requirement. Therefore, in order to deal with such a problem, a series multistage light condensing system as shown in FIG. 3 of JP-A-59-123,517 has been proposed. However, in this method, as the number of light collecting stages increases, the utilization rate of laser power becomes higher than that in the above method, but the reactor becomes enormous in length and it is difficult to secure the stability of the optical axis. However, there is a problem that the loss of laser energy that does not contribute to the reaction due to the absorption of the raw material before and after each focus is large. As a measure against the former problem, a multi-reflecting mirror pair as shown in FIG. 1 of JP-A-54-12 / 290 is proposed as a method in which the reactor length is short and the laser power can be effectively utilized. There is an example of a reactor provided with. In this case, since overlapping is repeated without focusing in multiple reflection of the beam, it is a very effective method when the required critical fluence is a low value of about 1 J / cm ² , but high fluence,
For example, when 5 to 6 J / cm ² is required, it is difficult to realize this in the entire overlapping area. Furthermore,
Since the surface shape of the reflecting mirror becomes complicated and a reaction occurs near the reflecting mirror, there is a problem that the reaction product stains the surface of the reflecting mirror and a stable reaction cannot be realized for a long time.

As a method of realizing reflection superposition using a simple optical system, the present applicants make the converging positions of outgoing and returning beams coincide and superimpose two or more beams in the vicinity of their focal positions. As a laser focusing method, an example of 2-pass superposition is presented in Japanese Patent Application Laid-Open No. 2-251,227, and an example of multi-pass reflection superposition is presented in Japanese Patent Application No. 2-126,836. In these methods, any desired fluence can be realized by appropriately selecting the curvature of the reflecting mirror, and the reflection beam optical axis and the laser oscillation optical axis are finally set to coincide with each other. Superimposition of more than the beam is surely realized. However, in these methods, if the number of reflection paths is increased and the laser propagation distance is increased in order to improve the utilization efficiency of laser energy, there is a problem that it becomes difficult to maintain stable alignment of the reflecting mirror.
Furthermore, in the multiple reflection system, the laser focusing profile changes sequentially due to the beam divergence caused by diffraction in the laser oscillator and the self-focusing / diffusing effect of the laser beam due to the reaction material. Existed, and it was impossible to use all the energy extracted from the laser oscillator for the reaction. Also, the residual laser energy that did not contribute to the reaction returns to the laser oscillator side, but in general the spatial mode of this reflected beam does not match that of the laser oscillator. Lost. In addition, in extreme cases, there is a possibility that the optical parts related to the laser oscillator may be damaged.

[0005]

The object of the present invention is to prevent the residual energy of the laser beam returning to the oscillator side, which is a problem in the above-mentioned two-pass superposition and multiple reflection superposition, from being lost due to diffraction loss and the like. A laser occupies the highest price in the laser photochemical vapor phase reaction process by realizing a simple device that effectively contributes almost all of the energy that can be extracted from the laser medium to the reaction medium by re-injecting it into the reaction substance and repeating this process. It is an object of the present invention to provide a reactor capable of significantly improving the utilization efficiency of beam energy as compared with the conventional method and realizing an inexpensive process.

[0006]

According to the present invention, a laser beam is condensed and introduced into a reaction region in a reaction vessel in which a gas phase raw material is present, and a desired chemical reaction is performed by using the light absorption property of the raw material. In a gas-phase photochemical reaction device using laser light for performing the above, a pair of condensing optical systems is provided outside a partial reflection mirror M ₂ of a laser resonator constituted by a total reflection mirror M ₁ and a partial reflection mirror M ₂ . The telescope is installed, the reaction container is installed at the laser condensing position between them, and the total reflection mirror M ₃ is installed behind the telescope, and the total reflection mirror pair M ₁ and M ₃ exists between them. Profile of the spatial mode of the laser beam formed in the Fabry-Perot resonator formed by the optical components M ₁ and M ₂ and M ₂ and M
Space profile between ₃ and total reflection mirror / partial reflection mirror pair M
A gas-phase photochemical reaction device using a laser beam, characterized in that the spatial profile of a laser beam formed in each Fabry-Perot resonator consisting of ₁ , M ₂ and M ₃ , M ₂ is matched. It is intended to provide an apparatus capable of effectively utilizing almost all of laser energy that can be extracted from a laser medium in a photochemical reaction.

[0007]

The present invention will be described in detail below. FIG. 2 shows an example of arrangement of optical components according to the present invention. The laser resonator for the laser medium is composed of a total reflection mirror M ₁ and a partial reflection mirror M ₂ which are arranged in a Littrow type and are made of grating so as to select the laser oscillation wavelength. The laser beam 1 output from the partial reflection mirror M ₂ which is a laser output mirror is condensed by the lens L ₁ and passes through the reaction container 2, and then is converted into a beam by the lens L ₂ and reaches the total reflection mirror M ₃ and is reflected. To be done. The reflected laser beam 1 is partially reflected through the lens L ₂ , the reaction container 2, and the lens L ₁ while maintaining the same profile as the beam profile in the path from the partial reflection mirror M ₂ to the total reflection mirror M _3. Return to mirror M ₂ . The laser beam 1 that reaches the partial reflection mirror M ₂ receives the partial reflection mirror M 2.
_It is split into two beams according to a reflectivity of ₂ , one being transmitted towards the total reflection mirror M _{1 and} the other being reflected towards the lens L ₁ . Here, since the spatial mode of the laser beam transmitted to the total reflection mirror M ₁ is controlled so as to match that of the original laser cavity constituted by M ₁ and M ₂ , diffraction loss is incurred. Instead, it reaches the total reflection mirror M ₁ , is reflected, and then reaches the partial reflection mirror M ₂ . In addition, since the spatial profile of the laser beam reflected toward the lens L ₁ matches that of the original oscillation beam,
The reaction vessel 2 is reached with the same spatial profile as the first beam. Mode between the total reflection mirror pair M _1, M ₁ of the resonator constituted by M _3, M-mode and M ₂ between _2, M ₃ is constituted by M _1, M ₂ and M _2, M ₃ respectively Since this matches the spatial mode of each resonator, the above operation repeats the reflection superposition an infinite number of times without suffering diffraction loss. Where lens L
_In principle, ₁ and L ₂ are non-reflection coated with respect to the laser oscillation wavelength, and the window for introducing the laser light of the reaction vessel 2 is set to Brewster's angle to prevent reflection loss. In the energy that can be extracted from the laser medium, all energy other than the reflection loss in the reflecting mirror is consumed in the reaction container 2 and contributes to the reaction. FIG. 3 schematically shows the flow of laser power in the above operation. In the figure, P ₀ is the power initially extracted from the laser oscillator, and r ₁ , r ₂ and r ₃ are the reflectances (r ₁ to r ₃ ...) of the reflecting mirrors M ₁ , M ₂ and M ₃ , respectively.
1, r ₂ <1), G represents the power gain when the laser medium makes one round trip, and α represents the ratio of the power absorbed by the reaction medium when making one round trip in the reaction vessel 2. As shown in the figure, the laser beam shows a complicated behavior because it is divided into two components each time it reaches the partial reflection mirror M ₂ , but the power (laser gain) that can be extracted from the laser medium while repeating reflection is increased. (Corresponding to G) is transferred to absorption power (corresponding to power loss α) by the reaction medium existing in the reaction container 2.

Next, a method of controlling the spatial mode in each resonator by the focal length of the condensing optical system constituting the telescope and the gap between them will be described. FIG. 4 shows that in the optical component arrangement of FIG. 2, l ₁ = 2000 mm, l ₂ = 200 mm, l ₃ = 14
20 mm, l ₄ = 200 mm f ₁ = f ₂ = 800 mm R ₁ = 4000 mm (concave surface), R ₂ = R ₃ = ∞ (flat surface),
The spatial propagation profile of the Gaussian beam under the condition of R ₄ = 4000 mm (concave surface) is A
It shows the result of analysis by ray tracing method using BCD matrix. FIG. 4 shows a profile of a Gaussian beam generated in a resonator composed of a total reflection mirror M ₁ and a partial reflection mirror M ₂ and a spatial profile in which the Gaussian beam propagates to the total reflection mirror M ₃ , drawn with a solid line. The profile of the beam reflected back from the mirror M ₃ to the partial reflecting mirror M ₂ is drawn by a chain line. As shown in the figure, under this condition, the reflected beam from the total reflection mirror M ₃ is directed to the total reflection mirror M ₃ rather than the position where the output beam from the partial reflection mirror M ₂ was first collected. It can be seen that the light is condensed at a close position. FIG. 5 regards M ₁ -M ₂ , M ₂ -M ₃ , and M ₁ -M ₃ as independent Fabry-Perot resonators under the same conditions as in FIG. Beam profile M ₁ -M ₃
Is a solid line and M ₁ -M _{2 is} a dash-dotted line and M ₂
It illustrates by broken lines with respect -M _3. As can be seen from the figure, since the spatial mode profiles for the respective resonators do not match, most of the laser beam hit from the M ₁ -M ₂ resonator is reflected by the total reflection mirror M ₃ and then most of it is reflected. Components are lost due to diffraction losses. On the other hand, only the gap between the telescopic lenses L ₁ and L ₂ is l ₃ =
6 and 7 show the same calculation results as those in FIGS. 4 and 5 when the total reflection mirror M ₃ is fixed, that is, l ₄ = 320 mm. It can be seen from FIG. 6 that the laser beam reflected by the total reflection mirror M ₃ maintains almost the same spatial profile and is reflected up to the partial reflection mirror M _{2 as described with reference} to FIG. It can be seen that the spatial mode profiles of the laser beams in the resonator are almost the same. It should be noted that the spatial modes can be made to completely match by further controlling the telescope lens gap l ₃ , but here an example is shown in which they are slightly shifted so that they can be distinguished. From the above results, it was found that it is possible to match the spatial mode profile in each resonator by controlling the gap between the telescope lenses L ₁ and L ₂ . The focal lengths f ₁ and f ₂ of the lenses L ₁ and L ₂ are appropriately selected according to the fluence required in the reaction container 2.

Next, the difference between the prior art and the present invention will be described. FIG. 8 shows the arrangement of the optical components to be evaluated in order to make a comparison with the prior art.
Compared with the above, the surface shape of the total reflection mirror M ₁ constituting the laser oscillator is flat, and the surface shape of the partial transmission mirror M ₂ on the side of the total reflection mirror M ₁ is concave, and in order to reduce the number of optical parts, The configuration is such that the scope lens L ₂ and the total reflection mirror M ₃ are the same. The above-mentioned structure is the same as that shown in FIG. 1 of Japanese Patent Laid-Open No. 2-251,227, which is a conventional technique, except for the shape of the reaction vessel. FIG. 9 shows the optical component arrangement of FIG. 8 with l ₁ = 2800 mm, l ₂ = 500 mm, l ₃ = 33.
60 mmf ₁ = 2000 mm R ₁ = ∞ (flat), R ₂ = 15000 mm (concave),
9 shows the results of ray tracing of the spatial propagation profile of the Gaussian beam under the conditions of R ₃ = ∞ (plane) and R ₄ = 1500 mm (concave surface).
Are drawn in the same manner as in FIGS. As shown in FIG. 9, the converging position of the output beam of the laser oscillator from the partial reflecting mirror M ₂ and the converging position of the reflected beam from the total reflecting mirror M ₃ are the same, but the space between the two beams is the same. The conditions are that the modes do not match. As a result, as shown in FIG. 10, the Gaussian mode spatial profiles for the three resonators do not match, resulting in a large energy loss due to diffraction loss. On the other hand, in the optical component arrangement of FIG. 8, l ₁ = 2800 mm, l ₂ = 500 mm, l ₃ = 40
10 mm f ₁ = 2000 mm R ₁ = ∞ (flat), R ₂ = 15000 mm (concave), R ₃
= ∞ (plane), R ₄ = 2000 mm (concave surface), the same ray tracing calculation results as in FIGS. 9 and 10 are shown in FIGS. 11 and 12. In this example, FIG.
Both 1 and FIG. 12 are represented by a single line because the respective spatial mode profiles are completely the same.
As described above, in the present invention, by controlling the focal length (radius of curvature R ₄ ) and the telescope gap (l ₃ ) of the spherical mirror corresponding to the telescope, the spatial modes can be matched to the respective resonators. Therefore, energy loss due to diffraction loss can be prevented.

FIG. 13 shows an arrangement example of an optical component according to still another embodiment of the present invention. In this example, in order to further reduce the number of optical components as compared with the arrangement of FIG.
This is an example in which the shape of the partial reflection mirror M ₂ is a meniscus convex lens and the partial reflection mirror M ₂ and the lens L ₁ are the same. The spatial mode behavior in this arrangement is as follows: 1 ₁ = 2000 mm, 1 ₂ = 3100 mm R ₁ = ∞ (flat), R ₂ = 4000 mm (concave), R ₃
= 1116 mm (convex surface), R ₄ = 1500 mm (concave surface), the calculation results drawn in the same manner as in FIGS. 4 and 5 are shown in FIG. 14 and FIG. 15, and the conditions for spatial mode matching are shown. l ₁ = 2000 mm, l ₂ = 2630 mm R ₁ = ∞ (flat), R ₂ = 4000 mm (concave), R ₃
16 and 17 show the calculation results in the case of = 1167 mm (convex surface) and R ₄ = 1500 mm (concave surface) in the same manner as in FIGS. 4 and 5. It is apparent that the spatial mode matching can be realized by controlling the position of the total reflection mirror M ₃ as in the above example.

Up to this point, the method of achieving spatial mode matching in three Fabry-Perot resonators has been described. Here, considering the laser resonator constituted by the total reflection mirror M ₁ and the partial reflection mirror M ₂ , installing the total reflection mirror M ₃ so that the spatial modes are matched is equivalent to providing an external resonator. .. This means that the laser light from the external resonator is fed back to the light wave resonating in the laser resonator, which causes phase interference between the resonance light and the feedback light. This phase interference generally does not cause a big problem for the short pulse oscillation operation, but can cause the instability of the oscillation in the case of the continuous wave oscillation operation. Such phase interference is M ₁ -M
And _second resonator, M ₂ -M ₃ difference in length of the resonator can be solved by controlling so as to be an integral multiple of the oscillation wavelength. For such control, for example, the total reflection mirror M ₁ or the total reflection mirror M ₃ is driven by a piezo element, and the drive voltage of the piezo element is set so that the output is maximized with reference to the laser output in the composite resonator. It is realized by controlling.

[0012]

EXAMPLES A gas phase photochemical reaction apparatus using laser light according to the present invention will be specifically described below based on Examples. FIG. 1 shows an example of a gas phase photochemical reaction device according to the present invention. In the figure, the laser oscillator 3 is an atmospheric pressure operating transversely excited (TEA) CO ₂ laser. The laser total reflection mirror M ₁ is a plane grating arranged in a Littrow type in order to select _one of a large number of CO ₂ laser oscillation lines, and its angle has an oscillation wavelength of 9.57 μm. Is set. The partial reflection mirror M ₂ which is an output mirror is a ZnSe partial transmission mirror having a concave surface with a radius of curvature of 15 m on the laser resonator side and a flat surface on the atmosphere side. Has been applied. The laser cavity length is 2.8 m. From the above laser oscillator, pulse half width of about 80 ns
ec. , A laser pulse having a pulse energy of 8 J / pulse is output. The ZnSe condensing lens L ₁ provided with a non-reflection coating having a focal length of 2 m is 50 to 50 from the partial transmissive mirror M _2.
A concave total reflection mirror M ₃ having a radius of curvature of 2 m is installed at a position of 4.0 cm from the position of cm. The above conditions are consistent with the calculation conditions of FIGS. 11 and 12. The total reflection mirror M ₃ is a Ge substrate provided with high reflection coating (reflectance 99.6%), and an energy meter 4 is installed behind the Ge substrate so that the laser in the compound resonator can be generated from slightly transmitted energy. Estimate energy. Further, a piezo element 5 is mounted on the back surface of the total reflection mirror M ₃ , and its drive voltage is feedback-controlled by the controller 6 so that the indicated value of the energy meter becomes maximum. The reaction vessel 2 is a cylindrical glass vessel, and an NaCl substrate whose incident angle is set to Brewster's angle is installed at both ends thereof as windows for introducing a laser beam. The reactant 7 is introduced from one end of the reaction container 2, receives laser irradiation, and then is discharged from the other end.

Carbon 13 isotope enrichment was carried out by using the system shown above using CHClF ₂ as a source gas. As a result, C ₂ carbon 13 is concentrated 50-fold of a natural concentration
F ₄ obtained as product, 13 C per laser pulse
A separation efficiency of 7 × 10 ⁻⁷ mol / pulse was obtained. 9 and 10 corresponding to the conventional method for comparison.
As a result of conducting a similar concentration experiment by changing the system to the condition of, the 13C separation efficiency per laser pulse was 3 × 10 ^-7 mo.
An efficiency of 1 / pulse was obtained. Therefore, according to the present invention,
The photochemical reaction efficiency per unit laser pulse energy is more than doubled as compared with the prior art.

In the above embodiments, the TEA laser, which is a typical pulse CO ₂ laser, is shown as an example.
The present invention is applicable to other pulse CO ₂ by Q switch technology or the like.
It goes without saying that the present invention can also be applied to lasers, continuous wave lasers, and other lasers such as solid-state lasers and dye lasers.

[0015]

As described above, according to the present invention, the power of the laser beam, which occupies the highest price in the gas phase photochemical reaction process by the laser beam, can be effectively utilized, and the photochemistry with respect to the laser energy can be effectively used. The reaction efficiency can be improved and various laser costs can be reduced, and there is an advantage that a low-cost laser gas phase photochemical reaction process can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a gas phase photochemical reaction device using laser light of the present invention.

FIG. 2 is a schematic view showing an arrangement example of optical components in the present invention.

FIG. 3 is a schematic diagram for explaining a laser power flow in the arrangement of FIG.

FIG. 4 is a diagram illustrating a condition in which spatial modes of three resonators cannot be matched in the optical component arrangement of FIG. 2, a Gaussian beam oscillated from the M ₁ -M ₂ resonator reaches a total reflection mirror M ₃ , and behavior up to the reflected partially transmissive mirror M ₂ is a graph showing the results of ray tracing.

FIG. 5 shows M ₁ −M ₂ and M ₂ −M under the same conditions as in FIG.
_3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

FIG. 6 is a diagram showing the arrangement of the optical components shown in FIG. 2 under the condition that the spatial mode matching of the three resonators corresponding to the present invention is almost taken; the Gaussian beam oscillated from the M ₁ -M ₂ resonator is totally reflected. led to the mirror M _3, it is a diagram showing the results of ray tracing behavior further to reach the reflected partially transmissive mirror M _2.

FIG. 7 shows M ₁ −M ₂ and M ₂ −M under the same conditions as in FIG.
_3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

FIG. 8 is a schematic diagram showing an arrangement example of another optical component in the present invention.

9 is a diagram showing a condition corresponding to the conventional method in the arrangement of the optical components shown in FIG. 8 in which spatial mode matching of three resonators cannot be achieved,
M ₁ -M ₂ Gaussian beam oscillated from the resonator is led to the total reflection mirror M _3, a diagram illustrating the behavior results of ray tracing of up further reach the reflected partially transmissive mirror M _2.

FIG. 10 shows M ₁ −M ₂ and M ₂ − under the same conditions as in FIG.
M _3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

11 is a total reflection mirror M of the Gaussian beam oscillated from the M ₁ -M ₂ resonator under the condition that the three resonators corresponding to the present invention have the spatial mode matching in the optical component arrangement of FIG. 8; Italy ₃ is a diagram showing the results of ray tracing behavior further to reach the reflected partially transmissive mirror M _2.

FIG. 12 shows M ₁ −M ₂ and M _{2 under the} same conditions as in FIG.
-M _3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

FIG. 13 is a schematic view showing an arrangement example of another optical component in the present invention.

[14] In the optical component arrangement of Figure 13 for the condition it is not possible to spatial mode matching of the three resonators, M ₁ -M ₂
It is a figure which shows the result of having carried out the ray tracing of the behavior until the Gaussian beam oscillated from the resonator reaches the total reflection mirror M ₃ and is further reflected and reaches the partial transmission mirror M ₂ .

FIG. 15 shows M ₁ −M ₂ and M _{2 under the} same conditions as in FIG.
-M _3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

16 is a total reflection mirror M of the Gaussian beam oscillated from the M ₁ -M ₂ resonator under the condition that the spatial mode matching of the three resonators corresponding to the present invention is achieved in the optical component arrangement of FIG. 13; Italy ₃ is a diagram showing the results of ray tracing behavior further to reach the reflected partially transmissive mirror M _2.

FIG. 17 shows M ₁ −M ₂ and M _{2 under the} same conditions as in FIG.
-M _3, M ₁ -M ₃ is a diagram showing a result of analyzing the spatial mode by ray tracing of a Gaussian beam, which may stand for the respective resonators.

[Explanation of symbols]

1: Laser beam 2: Reaction vessel 3: Laser oscillator 4: Energy meter 5: Piezo element 6: Controller 7: Raw material gas M ₁ , M ₃ : Total reflection mirror M ₂ : Partial reflection mirror L ₁ , L ₂ : Lens

Front page continuation (72) Inventor Tatsuhiko Sakai 5-10-1, Fuchinobe, Sagamihara City, Kanagawa Prefecture, Electronics Research Laboratory, Nippon Steel Corporation

Claims (4)

[Claims] 1. A laser beam for converging a laser beam and introducing it into a reaction region in a reaction vessel in which a gas-phase raw material is present, and performing a desired chemical reaction using the light absorption characteristics of the raw material. In the above gas-phase photochemical reaction device, a telescope consisting of a pair of condensing optical systems is installed outside the partial reflection mirror M ₂ of the laser resonator constituted by the total reflection mirror M ₁ and the partial reflection mirror M ₂ , and in between. laser condensing the reaction vessel was placed in position, further established the total reflection mirror M ₃ in the rear of the telescope, the total reflection mirror pair M _1, M ₃ and Fabry-Perot resonator formed of the optical component that exists between them The spatial profile between M ₁ and M ₂ and the spatial profile between M ₂ and M ₃ of the spatial mode of the laser beam formed at are the total reflection mirror / partial reflection mirror pairs M ₁ , M ₂ and M ₃ ,
A gas-phase photochemical reaction device using laser light, characterized in that it matches the spatial profile of a laser beam formed in each Fabry-Perot resonator made of M ₂ . 2. A focal length of a condensing optical system which constitutes a telescope of a spatial mode of a laser beam formed in a Fabry-Perot resonator consisting of a total reflection mirror pair M ₁ and M ₃ and optical components existing between them. The gas-phase photochemical reaction device using laser light according to claim 1, characterized in that it is controlled by the gap between them. 3. A laser beam between M ₁ and M ₂ in a composite resonator constituted by a group of reflection mirrors M ₁ , M ₂ and M ₃ , a total reflection mirror M ₁ and a partial transmission mirror M _2. And a means for controlling the positions of the total reflection mirrors M ₁ to M _{3 in} the optical axis direction on the basis of the laser output in the compound resonator so that the laser beams in the laser resonator are synchronized in phase. A gas phase photochemical reaction device using the laser beam according to claim 1. 4. A gas phase using a laser beam according to claim 1, wherein one or both of a pair of focusing optical systems constituting the telescope coincide with the total reflection mirror M ₃ or the partial transmission mirror M _2. Photochemical reactor.