JPH0794811A - Semiconductor laser exciting solid-state laser apparatus - Google Patents

Abstract

PURPOSE:To enable an increase in the number of semiconductor lasers and also enable an improvement in output of LD exciting solid-state laser apparatus. CONSTITUTION:Since laser resonators are formed in such a number corresponding to the number of microspherical surfaces 15 by forming a plurality of recessed microspherical surfaces 15 at the surface, opposed to the other end surface 8a of a rod 7, of an output mirror 14 arranged in the side of the other end surface 8a of a solid-state laser rod 7 for inputting the LD beam 4 for excitation to the one end surface 8, the oscillation region 9 in the solid-state laser rod 7 can be spread. Therefore, the number of LD beams 4 for excitation can be increased and a remarkable improvement of output of the LD exciting solid-state laser apparatus can also be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor laser pumped solid state laser device.

[0002]

2. Description of the Related Art An optical arrangement of a conventional semiconductor laser (Laser-Diode; hereinafter abbreviated as LD) pumped solid-state laser device is shown in FIG. The optical arrangement shown in FIG. 2 is an arrangement called a fiber bundle end face excitation system. The operation of the conventional device shown in FIG. 2 will be described. The laser light emitted from one pumping LD is radiated to the outside via the optical fiber 2.

The end of the optical fiber 2 is formed into a bundle fiber 3, and the LD light 4 emitted from the optical fiber 2 is collimated by a collimator lens 5 and condensed by a condenser lens 6 to form a laser medium. The light is incident on the solid-state laser oscillation region 9 from the end face 8 of the solid-state laser rod 7.

The end face 8 of the laser rod 7 is provided with a coating that transmits the LD light 4 well and reflects the solid-state laser oscillation light 10. On the other hand, most (90 to 99%) of the solid-state laser oscillation light 10 is reflected on the concave surface 12 side of the concave mirror 11,
The coating is slightly (1-10%) transparent.

The central axes of the end surface 8 of the laser rod 7 and the concave surface 12 of the concave mirror 11 coincide with each other and constitute a laser resonator. The solid-state laser oscillation light 10 excited by the LD light 4 is amplified by the resonator, and a part thereof becomes the output light 13 and is emitted from the concave area 11.

Generally, the LD pumped solid-state laser device has a characteristic of high oscillation efficiency (output power / pumping light power) as compared with the conventional rare gas discharge lamp pumped solid-state laser device. There is a reason. One is L
This is because the oscillation wavelength of D is single, and by making it coincide with the absorption wavelength band of the laser rod, the absorption rate is improved.

The other one is that the size of the light source of the LD is smaller than that of the conventional rare gas discharge lamp (1 mm ² or less) and the divergence angle is small. This is because the light can be concentrated and injected into the oscillation region of the laser, and the spatial matching between the excitation light and the oscillation region of the solid-state laser is very good. This high spatial alignment has the additional benefit of providing a high quality output beam (single mold).

As described above, the LD-pumped solid-state laser device is excellent, but has a drawback that the output is smaller than that of the conventional solid-state laser. This is because the output of the pumping LD is as small as about several watts, and even if it oscillates with high efficiency, the absolute output is far short of the conventional lamp pumping. By the way, the lamp output is several kilowatts or more at the maximum level, and the oscillation efficiency is 1/1 of that of semiconductor laser excitation.
It is as low as 0 or less, but the absolute output is much larger.

Therefore, pumping by a plurality of LDs is required. As shown in FIG. 2, the optical fibers 2 are connected to the pumping LDs 1, respectively, and the tips of the optical fibers 2 are connected via lenses 5 and 6. The end face 8 of the solid-state laser rod 7 was irradiated with the LD light 4.

[0010]

In the conventional LD pumped solid state laser device of the end face pumping type of fiber bundle,
Although it was possible to excite with a plurality of LDs and the output could be improved, there were still the following problems.

That is, in order to increase the output of the solid-state laser,
The number of LDs should be increased. However, as the number of LDs increases, the area of the end face of the bundle increases, so the diameter of the excitation laser beam narrowed down by the condenser lens 6 increases. When the beam diameter becomes thicker, the beam diameter becomes larger than the oscillation beam diameter of the solid-state laser, so that the spatial matching with the oscillation region of the solid-state laser deteriorates and the oscillation efficiency decreases.

Usually, the oscillation beam diameter of a solid-state laser is 500
Since it is less than μm and the diameter of the optical fiber is similar,
In the case of the conventional device, the number of LDs was limited to about 10. Therefore, the output of the solid-state laser could not be improved any further. The present invention is intended to solve the above problems.

[0013]

The LD-pumped solid-state laser device of the present invention serves as an output mirror in an LD-pumped solid-state laser device that oscillates a laser by exciting the solid-state laser rod by injecting LD light into the solid-state laser rod. It is characterized by using an output mirror integrally formed by arranging a plurality of concave minute spherical surfaces facing the rod.

[0014]

In the above, since the number of laser resonators corresponding to the number of microspheres of the output mirror is formed, the oscillation region in the solid-state laser rod expands, and when LD light enters the rod, the microspheres are formed. It is possible to generate the number of solid-state laser oscillation lights corresponding to the number.

In the present invention, as described above, since the oscillation region in the solid-state laser rod is expanded as compared with the conventional device, it is possible to increase the number of LD light for excitation.
It is possible to significantly improve the output of the pumped solid-state laser device.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An LD pumped solid state laser device according to an embodiment of the present invention is shown in FIGS. This embodiment shown in FIGS. 1A and 1B is a plurality of pumping LDs that emit LD light 4.
1, an optical fiber 2 having one end connected to each of the pumping LDs 1 and an LD light 4 emitted from the pumping LD 1 having a bundle fiber 3 formed at the other end, and an LD emitted from the optical fiber 2 Collimating lens 5 with light 4
And an LD pumped solid-state laser device provided with a solid-state laser rod 7 which is incident from one end face 8 thereof via a condenser lens 6, in addition to the solid-state laser rod 7 provided on the anti-collection lens 6 side of the solid-state laser rod 7. Output mirror 1 having a plurality of concave minute spherical surfaces 15 provided on the surface facing the end surface 8a
It is equipped with 4.

In the above description, each of the minute spherical surfaces 15 provided on the surface of the output mirror 14 has its central axis perpendicular to the incident side end surface 8 of the LD light 4 of the solid-state laser rod 7.
Since the respective laser resonators are formed, the number of the solid-state laser oscillation lights 10 is the same as the number of microspheres, and the entire forehead region in the solid-state laser rod 7 is almost the oscillation region 9.

Therefore, as in the conventional device, the exciting LD is used.
When the LD light 4 emitted from No. 1 enters the solid-state laser rod 7 from the end face 8 via the optical fiber 2, a plurality of solid-state laser oscillation lights 10 oscillate, and a part thereof becomes the output light 13 and is output. It is emitted from the mirror 14.

As described above, almost the entire region within the solid-state laser rod becomes the oscillation region, its cross-sectional area is increased and the number of pumpable LDs can be increased as compared with the conventional device, so that the laser output is increased. Is proportionally improved. For example, if the rod diameter is about 5 mm, the diameter of the microsphere is 1 mm.
This is sufficient, and more than 10 oscillating beams can be formed, so that the output is increased by 10 times.

[0020]

According to the LD pumped solid-state laser device of the present invention, the surface of the output mirror disposed on the other end surface side of the solid-state laser rod which enters the LD light for pumping into one end surface, faces the other end surface of the rod. By forming a plurality of concave microspheres in the laser cavity, the number of laser resonators corresponding to the number of microspheres is formed, so that the oscillation region in the solid-state laser rod is expanded and the number of LD light for excitation is increased. Can be LD
It is possible to significantly improve the output of the pumped solid-state laser device.

[Brief description of drawings]

FIG. 1 is an explanatory view of an LD-pumped solid-state laser device according to an embodiment of the present invention, in which (a) is a plan view and (b) is A- in (a).
FIG.

2A and 2B are explanatory views of a conventional semiconductor laser pumped solid-state laser device, FIG. 2A is a plan view, and FIG. 2B is a view taken along the line BB of FIG.

[Explanation of symbols]

 1 LD 2 Optical fiber 3 Bundle fiber 5 Collimating lens 6 Condensing lens 7 Solid-state laser rod 8, 8a End surface 14 Output mirror 15 Micro spherical surface

Claims (1)

[Claims] 1. In a semiconductor laser pumped solid-state laser device that excites a solid-state laser rod by injecting the semiconductor laser light into the rod to oscillate the solid-state laser rod, a plurality of concave microspheres facing the rod are used as output mirrors. A semiconductor laser pumped solid-state laser device comprising an output mirror integrally formed side by side.