JPH06268294A - Laser oscillator - Google Patents

Abstract

PURPOSE:To prevent the pumping light from a pumping lamp from reaching the sealing material on the outer periphery of the end portion of a rod for generating a laser light pulse thereby to provide a long life to the sealing material, by integrally forming a reflective film for reflecting the pumping light through the rod for generating a laser light pulse in a portion which is put in contact with the sealing material. CONSTITUTION:A reflective film 11 is integrally formed on a ground surface 10b of a rod 10 so as to cover this, by gold plating, gold evaporation, dielectric multilayered film or the like. The area where the reflective film 11 is formed is set so that it does not project beyond the distal end of a rod holder 4 and forms a portion in contact with a sealing material 9. Part of the pumping light travels from the rod 10 to the direction in which the sealing material is irradiated. However, since the reflective film 11 is interposed in its light path, the pumping light is fully reflected at the reflective film 11, thereby preventing the generation of a phenomenon that the pumping light reaches the sealing material 9. Since the reflective film 11 is formed on the ground surface 10b, the adhesion is good, whereby the reflectivity of the pumping light can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillating device, and more particularly to a technique for preventing a pumping light from a pumping lamp from reaching a sealing material to extend the life of the sealing material. .

[0002]

2. Description of the Related Art In a rod-type solid-state laser such as Nd / YAG, a plurality of laser light generating rods (hereinafter, The rods (abbreviated as rods) are arranged in a cascade on the same optical axis.

Further, as shown in FIG. 3, an appropriate number of excitation lamps 2 such as arc lamps for generating excitation light are arranged on the side of the rod (laser light generating rod) 1 and the excitation lamp 2 is provided. A reflective cylinder (reflection surface) 3 for reflecting the excitation light and irradiating the rod 1 in a concentrated manner is arranged around the.
Then, laser light is generated by applying excitation light to each of the plurality of rods 1, and the rods 1 and 2 are oscillated by reciprocating between the rear mirror and the output mirror that face each other at the above-mentioned separated positions. In FIG. 3, reference numeral 4 is a rod holder, 5 is an electrode, 6 is a lamp holder, 7 is a flow tube, 8 is a cooling water annular flow path,
9 is a sealing material (O-ring).

On the other hand, in the laser oscillating device, the rod 1 is heated by the excitation energy and its temperature rises, so that the optically convex lens is generated based on the difference in thermal expansion and the change in the refractive index due to internal stress. A phenomenon called a thermal lens effect having the property of is likely to occur. Therefore, the parallel state between the path of the laser beam between the rods 1 and the optical axis is broken, and the volume and laser volume that contribute to oscillation inside the rod 1 tend to decrease, and the oscillation efficiency tends to decrease. .

[0005]

In such a laser oscillating device, in order to keep the rod 1 at a low temperature, a sealing material 9 is arranged at the end of the flow tube 7 to secure the sealing property. It is desirable to flow cooling water through the cooling water annular flow path 8 to cool the rod 1. However, as shown by the chain line in FIG. 3, the excitation light from the excitation lamp 2 is applied to the flow tube 7 and the rod 1. It may happen that the sealing material 9 is reached via the. Further, since the excitation light contains a large amount of short-wavelength ultraviolet components, the structure of the sealing material 9 undergoes a chemical change, and the deterioration of the sealing property due to the progress of deterioration and the chemical change. The gas generated along with it contaminates the end surface of the rod 1 and deteriorates the laser characteristics within a long period of time.

The present invention has been made in view of these circumstances, and an object thereof is to prevent the excitation light from the excitation lamp from reaching the sealing material and to extend the life of the sealing material. .

[0007]

[Means for Solving the Problems] The following proposals have been made to solve these problems. A laser oscillator in which cooling water is caused to flow between the laser light generating rod and the flow tube surrounding it, and a sealing material is arranged between the outer peripheral surface of the end portion of the laser light generating rod and the rod holder. Therefore, a configuration is adopted in which a reflection film that reflects the excitation light that has passed through the laser light generation rod is integrally formed at the contact portion with the sealing material on the outer peripheral surface of the end portion of the laser light generation rod.

[0008]

Function The excitation light traveling toward the sealing material via the laser light generating rod is reflected by the reflection film on the outer peripheral surface of the end portion of the laser light generating rod and can reach the sealing material directly. The occurrence of the phenomenon that the excitation light irradiates the sealing material is suppressed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the laser oscillator according to the present invention will be described below with reference to FIGS. In each drawing, reference numeral 10 is a rod (laser light generation rod), 11 is a reflective film, 12 is an insert member, 13 is a threaded portion, 14 is an outer sealing material, 15 is a water supply / drainage annular flow path, 1
Reference numeral 6 is a connection channel.

The rod (rod for generating a laser beam) 1
Even if it is 0, a rod-type solid-state laser such as Y
An AG (yttrium-aluminum-garnet) solid-state laser is used, but as shown in FIGS. 1 and 2, a fine uneven surface 10a is formed on most of the outer peripheral surface and an end portion with which the sealing material 9 contacts. On the outer peripheral surface, a polished surface 10b is formed by polishing the outer peripheral surface into a mirror surface.

The reflecting film 11 is a polished surface 1 of the rod 10.
0b is integrally formed by gold plating, gold vapor deposition, a dielectric multilayer film or the like so as to cover it. Then, the reflective film 11
As shown in FIG. 1, the forming range of is set such that it does not protrude from the tip of the rod holder 4 and is a contact portion with the sealing material 9.

The insert member 12 is inserted into the inside of the rod holder 4, and its tip and the rod holder 4 are inserted.
The sealing material 9 with the inward flange 4a arranged at the tip of the
Is compressed to bring the sealing material 9 into close contact with the reflective film 11, so that the sealing property between the inward flange 4a, the reflective film 11 and the insert member 12 is set.

The threaded portion 13 serves to assemble the rod holder 4 and the insert member 12 in a screwed state and to perform assembly and sealability by relative rotation operation of the rod holder 4 and the insert member 12.

The outer seal material 14 is disposed between the rod holder 4 and the flow tube 7 in an interposing state.
A sealability between them is obtained.

The water supply / drainage annular flow path 15 and the connection flow path 16
Is formed between the outer peripheral portion of the rod holder 4 and the inner surface of the flow tube 7, and connects the cooling water annular flow path 8 to water supply means and drainage means.

In the laser oscillating device thus constructed, the rod 10 is supplied by supplying or draining water from the water supply / drainage annular flow path 15 to the cooling water annular flow path 8 via the connection flow path 16. Cooling is performed, and at this time, sealing is performed by the sealing material 9.

When the excitation light from the excitation lamp 2 described in FIG. 3 reaches the rod 10 via the flow tube 7, the uneven surface 10a is formed on most of the outer peripheral surface of the rod 10. , The excitation light is scattered on the outer surface of the rod 10 by the uneven surface 10a,
Although it is not guided to the inside of the rod and does not form a sharp focus inside the rod, the excitation light that spreads inside the rod 10 excites the laser substance in the entire traveling path to generate laser light. The laser can be excited over a wide range.

A part of the excitation light is directed from the rod 10 in the direction of irradiating the sealing material 9 as shown by the chain line in FIG. However, since the reflection film 11 is interposed in the optical path, the excitation light is totally reflected by the reflection film 11,
The occurrence of the phenomenon that the excitation light reaches the sealing material 9 is suppressed. In this case, since the reflection film 11 is formed on the polishing surface 10b, the adhesion is improved, the dimensional accuracy is high, and the reflectance of the excitation light is increased to increase the energy. Generation of loss is suppressed and high temperature is prevented.

[0019]

The laser oscillating device according to the present invention has the following effects. By adopting a configuration in which a reflective film is integrally formed on the contact surface of the outer peripheral surface of the rod with the seal material, the excitation light is reflected by the reflective film even in the direction of the seal material via the rod. To prevent the deterioration of the sealing property due to deterioration of the sealing material and the occurrence of chemical contamination and contamination of the rod due to the generation of gas, and to maintain the laser characteristics for a long period of time. You can

[Brief description of drawings]

FIG. 1 is a front sectional view with a part omitted showing an embodiment of a laser oscillator according to the present invention.

FIG. 2 is a front sectional view for explaining the influence of excitation light in the example of FIG.

FIG. 3 is a front cross-sectional view showing a conventional example of a rod holder and a lamp holder in a laser oscillator, with some parts omitted.

[Explanation of symbols]

 2 Excitation Lamp 3 Reflecting Tube (Reflecting Surface) 4 Rod Holder 4a Inward Flange 7 Flow Tube 8 Cooling Water Circular Flow Path 9 Sealing Material (O Ring) 10 Rod (Laser Light Generation Rod) 10a Uneven Surface 10b Polishing Surface 11 Reflective Film 12 insert member 13 screw part 14 outer seal material 15 water supply / drainage annular flow path 16 connection flow path

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiro Nishimi 3-15-15 Toyosu, Koto-ku, Tokyo Ishikawajima Harima Heavy Industries Co., Ltd. Toji Technical Center (72) Inventor Shono Toyosu, Koto-ku, Tokyo 3-chome 1-15 Ishikawajima Harima Heavy Industries Co., Ltd. Toji Technical Center

Claims (1)

[Claims] 1. Cooling water is caused to flow between a laser light generating rod and a flow tube surrounding the rod,
A laser oscillating device in which a sealing material is arranged between an outer peripheral surface of an end portion of a laser light generating rod and a rod holder, wherein a laser beam is applied to a contact portion of the outer peripheral surface of the end portion of the laser light generating rod with the sealing material. A laser oscillating device, wherein a reflecting film for reflecting the excitation light passing through the light generating rod is integrally formed.