JPH01230276A - Solid laser beam oscillating device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a solid-state laser oscillation device equipped with a solid-state laser medium such as YAG.

(Prior Art) In general, in a solid-state laser oscillation device, a laser rod such as YAG, which is a laser medium, is always water-cooled during oscillation in order to prevent thermal effects during excitation. The laser rod is held at both ends by cylindrical holders, but an O-ring is interposed between the laser rod and the holder to create a watertight structure so that cooling water does not flow around the end surfaces of the laser rod. This prevents the end face from being contaminated by cooling water and prevents a drop in oscillation output. However, even with water cooling as described above, it is difficult to completely eliminate thermal effects, and if laser oscillation continues for a long time, the laser rod will optically change and the oscillation optical axis of the laser beam will shift. In addition, especially in so-called multi-stage laser oscillators in which multiple laser rods are arranged in series, the resonance mode becomes complex, and there is a high probability that the laser beam emitted from one rod end face will not enter the other laser rod end face. . For this reason, there is a problem in that the laser beam, which is reflected from the resonant mirrors provided at both ends of the holder and whose optical axis is shifted, deviates from the end face of the laser rod, irradiates the O-ring, and deteriorates it. In order to solve this problem, for example,
The following technology is disclosed in the issue. That is, as shown in FIG. 3, a laser rod (3) and an excitation lamp (4) are incorporated in a main body (2) filled with cooling water (1). In order to fix the laser rod (3), both ends of it are attached to a holder (2) fixed to the main body (2).
5) is inserted and held. In this holding, a set screw (8) is screwed through an O-ring (6) as a sealing material and a washer (7). In addition, the laser rod (
A plate (9) is provided on the end surface (3a) of 3) so as to annularly cover the outer periphery of this end surface (3a), and a plate (9) is provided on the end surface (3a) of the end surface (3).
10) is fixed within the holder (5).

(Problem to be Solved by the Invention) In the conventional configuration described above, the laser beam whose optical axis has shifted during laser oscillation is blocked by the plate (9), but the plate (9)
Sputtering occurs in the annular part of the laser rod, and the gasified material adheres to and contaminates the end face (3a), reducing oscillation efficiency and causing the end face to heat up and damage the laser rod. Ta.

In addition, if this sputtering continues for a long time, a hole will appear in a part of the plate (9), and the laser beam with the optical axis will leak through the hole, causing the O-ring (6) to deteriorate. . The present invention has been made in view of these circumstances, and provides a solid-state laser oscillation device that prevents the deterioration of the watertight sealing material, thereby preventing the end face of the solid-state laser medium from being contaminated, and stabilizing laser oscillation. The purpose is to provide

[Configuration of the Invention (Means and Effects for Solving the Problems) An excitation lamp, a solid-state laser medium excited by the excitation lamp, and both ends of this solid-state laser medium held watertight so that the inside is the above-mentioned solid-state laser medium. a pair of holders formed in a cylindrical part having a cross section similar to that of the end face and having a small cross-sectional area;
The holder is configured to include a pair of reflecting mirrors that are provided on both ends of the holder and constitute an optical resonator, so that sputtering is less likely to occur during laser oscillation, and the end face of the solid-state laser medium is also less likely to be contaminated.

(Example) EMBODIMENT OF THE INVENTION Hereinafter, this invention will be explained based on drawing which shows an Example.

Note that parts common to those in FIG. 3 are given the same reference numerals, and since the structure is symmetrical about the axis of the solid-state laser medium, the structure on the left side will be described. That is, in FIG. 1 showing the left side above, the laser rod (3)
The end of the holder (15) is fixed to the main body (2).
kept watertight. The inside of the holder (15) is formed into a holding part (15a) for the laser rod (3) and a cylindrical part (15b) having a smaller diameter than the laser rod (3) and longer than the holding part (15a). There is. Holding part (15a)
The boundary between the laser rod (3) and the cylindrical portion (15b) is formed on a tapered surface (15c) facing toward the end surface (3a) of the laser rod (3). In the holding part (15a), a male thread is formed on the outer circumferential part, and the end face is protruded inward, and the insertion part is an annular face (
16). The end of the laser rod (3) is inserted into this holding part (15a), and the O-ring (6) that was previously inserted into the outer surface of the annular surface (16) is inserted, and the O-ring (6) is inserted in the same manner as the O-ring (6). A fastening body (17) inserted in advance and having a female thread on the inside is screwed together. This screwing deforms the O-ring (6) and attaches it to the laser rod (3).
The laser rod (3) is held in close contact with the laser rod (3) in a watertight manner. On the other hand, as shown in FIG. 2, a plurality of grooves (18) are radially carved on the outer side of the cylindrical portion (15b) of the holder (15). These grooves (18) each extend near the other end of the holder (15).

The other end of the holder (15) is inserted into a holder (19) fixed to the outer end of the main body (2), and is fitted with an O-ring (20).
), making it watertight. An annular flow path (21) communicating with the valley groove (18) is provided inside the holder (19). This flow path (21) communicates with a drain pipe (22) connected to the holder (19) through a flow path (23).

By the way, the laser rod (3) is coaxially surrounded by a glass tube (24). This glass tube (24) is a fastener (
The end portion of the side plate (25) is fitted into a part of the side plate (25) which is inserted through the side plate (25). Glass tube (24)
Cooling water is introduced into the space between the side plate (25) and the tightening body (17), the groove (18) and the channel (21), (
23) and exits to the drain pipe (22). Note that (26) is a communication passage that continues to a cooling channel for an excitation lamp (not shown), and (27) is one of the resonant mirrors forming the optical resonator.

In the above configuration, the optical axis is shifted and the light is blocked by the cylindrical part (15a), and the Taber surface (15C)
The laser is reflected on the end face of the laser rod (3), and the O ring (6
) cannot be irradiated with a laser beam whose optical axis is shifted. Furthermore, this cylindrical portion (15a) functions as an aperture, making it unnecessary to provide a separate aperture outside the laser resonator.

Furthermore, since the holder (15) is constantly cooled as a whole, the occurrence of sputtering is extremely reduced.

In addition, in the above embodiment, a groove (
18) to form a cooling water flow path, however, the present invention is not limited to this, and grooves may be radially carved on the main body (2) side and these may be used as flow paths. Further, the length ratio in the axial direction of the holding part (15a) and the cylindrical part (15b) is the length ratio of the cylindrical lock part (
It is better for L5a) to be as long as possible.

In the above embodiment, the solid laser medium is a rod with a circular cross section, but the present invention is also applicable to a laser oscillation device using a so-called slab type laser medium with a rectangular cross section. In this case, the cross section of the cylindrical portion is formed to have a cross-sectional shape that is similar to the end face of the laser medium and has a small area.

[Effects of the invention] The laser beam that is misaligned with the optical axis is reliably prevented from entering the O-ring, the O-ring maintains watertightness, and the occurrence of sputtering is extremely reduced, so that the laser beam that is misaligned with the optical axis is prevented from entering the O-ring. This eliminates contamination and allows stable laser oscillation to be maintained for a long time. Furthermore, since the aperture operating portion is formed inside the holder, the device can be made more compact.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
A cross-sectional view taken along line A--A in FIG. 3 is a cross-sectional view showing a conventional example. (3) Laser rod (15) Holder (15a) Holding part (15b) Cylindrical part Cooling water (cooling means) (22)... drain pipe

Claims (2)

[Claims] (1) An excitation lamp, a solid-state laser medium excited by this excitation lamp, and both ends of this solid-state laser medium are held watertight, and the interior has a cross section similar to the end face of the solid-state laser medium and has a small cross-sectional area. What is claimed is: 1. A solid-state laser oscillation device comprising: a pair of holders formed in a cylindrical portion; and a pair of reflecting mirrors provided at both ends of the holder and forming an optical resonator. (2) The solid-state laser oscillation device according to claim 1, wherein the holder has a cooled outer side.