JP2930482B2 - Conical Raman laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Raman laser device and, more particularly, to a Raman laser device improved so as to improve Raman conversion efficiency.

[0002]

2. Description of the Related Art A Raman laser reflects a laser beam multiple times between a pair of mirrors, and converts the wavelength of the laser beam to a longer wavelength side by rotational scattering transition of gas molecules (Ishikawajima Harima Technical Report Vol. 24) No. 5, September 1984), an example of such a conventional Raman laser device is shown in FIG.

As shown in FIG. 1, end plates 22, 23 are provided on both end flanges 3A, 3B of a cylinder 3 holding a laser medium gas.
Are attached and the short cylinders 20 and 21 are fixed inside the respective end plates 22 and 23.
Have concave mirrors 1 and 2 inserted therein. The end plate 22 and the concave mirror 2 are provided with a window 4 and an incident hole 2A, respectively, for allowing a laser beam to enter from the outside. The end plate 23 and the concave mirror 1 have an emission port for emitting a laser beam. A hole 1A and a window 5 are provided.

Accordingly, as shown in FIG.
Passes through the window 4 of the end plate 22 and the entrance hole 2A of the concave mirror 2 and enters between the concave mirrors 1 and 2, and is multiple reflected by the multiple reflection portion 24 between the concave mirrors 1 and 2. Then, the laser beam 31 that has become a Raman laser due to the multiple reflection is reflected by the concave mirror 1.
Through the exit hole 1A and the window 5 of the end plate 23.

[0005]

In the above-mentioned conventional Raman laser device, when the laser beam 30 is multiply reflected between the concave mirrors 1 and 2, it concentrates particularly on the central portion of the cylinder 3.
Due to the energy of the laser light, the temperature of the laser medium gas may increase, and the Raman conversion efficiency may decrease. Therefore, in order to improve the Raman conversion efficiency and increase the output of the Raman laser, it is an issue how to cool the laser medium gas.

In particular, the greater the incident laser output or the greater the number of pulses per unit time of the pulsed incident laser light, the greater the problem. The present invention
An object of the present invention is to provide a Raman laser device capable of keeping the temperature of a laser medium gas low and improving Raman conversion efficiency.

[0007]

According to the structure of the present invention for achieving the above object, a main container for holding a laser medium gas is adjusted to the shape of multiple reflection of a laser beam so that the center has a small diameter and both ends have a large diameter. It is characterized in that it has a continuous shape.

[0008]

According to the present invention, since the main body container has a conical shape with a small diameter at the center and a large diameter at both ends in accordance with the shape of the multiple reflection of the laser beam, the outermost shell of the multiple reflection portion of the laser beam is formed. The distance from the body can be significantly reduced, especially at the center. Therefore, the heat of the laser medium gas is efficiently transmitted to the main body container. Therefore, the laser medium gas can be efficiently cooled from outside the main body, and the temperature of the laser medium gas can be kept low.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention. As shown in the figure, end plates 22 and 23 are attached to both end flanges 3A and 3B of a main body container 35 holding a laser medium gas, and short cylinders 20 and 21 are fixed inside the end plates 22 and 23, respectively. Further, concave mirrors 1 and 2 are inserted into the short cylinders 20 and 21, respectively.

The end plate 22 and the concave mirror 2 are provided with a window 4 and an incident hole 2A, respectively, for allowing a laser beam to enter from the outside, and the end plate 23 and the concave mirror 1 are provided for emitting the laser beam. Are provided with an emission hole 1A and a window 5, respectively. Here, the shape of the main body container 35 is a continuous shape having a small diameter at the center and large diameters at both ends in accordance with the shape of the laser beam multiple reflection. In other words, the shape of the main body container 35 is similar to a shape obtained by connecting two cones with the vertexes facing each other.

As described above, in the present embodiment, the main container 35 is used.
Is smaller in the center, so that the distance from the laser light multiple reflection portion 24 is reduced, and the heat of the laser medium in the main body container 35 is efficiently transmitted to the main body container 35. For this reason, if the laser medium is cooled from the outside of the main body container 35, it is possible to suppress the temperature rise of the laser medium and maintain the efficiency of the Raman conversion. However, cooling is
Natural cooling may be used, but it is also conceivable to provide a cooling device outside the main body container 35 by mechanical cooling, electronic cooling, or the like.

Here, from the viewpoint of improving the cooling efficiency, it is considered desirable that the distance between the laser beam multiple reflection section 24 and the main body container 25 be as narrow and constant as possible. Further, the material of the main body container 35 may be determined in consideration of the cooling efficiency. Furthermore, since the shape of the laser beam multiple reflection portion 24 depends exclusively on the radius of curvature of the concave mirrors 1 and 2, the shape of the main body container 35 can be appropriately changed in design according to the shape of the concave mirrors 1 and 2. .

Next, another embodiment of the present invention is shown in FIG.
In this embodiment, as shown in FIG. 2, the central portion of the main body container 36 is formed as a cylindrical portion 3X in order to ease the restrictions on manufacturing. In this embodiment, the central portion of the main body
Although it is set to X, the same operation and effect as those of the above-described embodiment can be obtained if the distance between the laser light and the multiple reflection unit is sufficiently reduced. The other configurations are the same as those of the above-described embodiment, and have the same effects.

[0014]

As described above in detail with reference to the embodiments, according to the present invention, the shape of the main body container is made smaller at the center and larger at both ends in accordance with the shape of the laser beam multiple reflection. In addition, the temperature of the laser medium gas can be kept low. Because of this,
Even when the energy of the incident laser is increased or the number of pulses of the pulsed incident laser light per unit time is increased, the laser can be efficiently converted into a Raman laser.

[Brief description of the drawings]

FIG. 1 is a sectional view of a conical Raman laser device according to one embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a conical Raman laser device according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional Raman laser device.

FIG. 4 is an explanatory diagram of multiple reflection of laser light.

[Explanation of symbols]

 1, 2 concave mirror 1A entrance hole 2A exit hole 3 cylinder 3A, 3B both ends flange 4,5 window 20,21 short cylinder 22,23 end plate 24 multiple reflection part 30 laser light 31 Raman laser light 35,36 main body container 3X Cylindrical part

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01S 3/30

Claims (1)

(57) [Claims] A main container for holding a laser medium gas has a small diameter at the center according to the shape of multiple reflection of laser light.
A conical Raman laser device having a conical shape with both ends having large diameters.