JPH07112084B2 - Array semiconductor laser pumped solid-state laser device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an array semiconductor laser pumped solid-state laser device that optically pumps a solid-state laser device by optically mixing array semiconductor laser outputs as a pumping light source with high efficiency. .

[Prior Art] Solid-state lasers using a semiconductor laser as an excitation light source are attracting attention because they can achieve high efficiency, long life, and miniaturization. In particular, in the end-face pumping method in which the solid-state laser is optically pumped from the optical axis direction (see, for example, Japanese Patent Laid-Open No. 58-52889), the pumping space by the output light of the semiconductor laser is well matched to the oscillation mode of the solid-state laser, thereby achieving high efficiency. Basic transverse mode oscillation can be realized with.

Since the semiconductor laser has a large beam divergence angle, it is necessary to dispose the condensing system close to the semiconductor laser for condensing.
It is not easy to collect oscillation light.

In order to increase the output of a semiconductor laser pumped solid-state laser, it is necessary to increase the output of a semiconductor laser for pumping. A semiconductor laser takes out laser light from a stripe-shaped active layer, but since output from a single stripe is limited,
In order to further increase the output, it is necessary to form an array in which a plurality of stripes are arranged.

[Problems to be Solved by the Invention] When such an array semiconductor laser is used as a pumping light source, the width of the array extends about 1 cm, and therefore a plurality of beams are formed into one spot shape by using an ordinary lens system. Since it is impossible to narrow down to 2, it is not possible to adopt the end face excitation method with good excitation efficiency, and it can be applied only to the side surface excitation method (see, for example, JP-A-1-107587).

The present invention has been made in view of the above circumstances, and condenses a plurality of beams with a large divergence angle emitted from a multi-striped array semiconductor laser so as to match the spatial mode of oscillation of the solid-state laser, and efficiently solid-state laser. An object of the present invention is to provide a semiconductor laser pumped solid-state laser device that can generate output light.

[Means for Solving the Problems] In order to achieve the above object, in an array semiconductor laser pumped solid-state laser device of the present invention, as an optical coupler for condensing array semiconductor laser output and optically pumping a solid-state laser element, The distributed index lenses are arranged corresponding to the respective stripes of the array semiconductor laser, and the array distributed refractive index lenses for collimating the respective stripe light of the array semiconductor laser and the respective striped light collimated are collectively condensed to form one. An aspherical lens used as a focusing lens for exciting the end face of the solid-state laser element was placed on top of each other.

In the above-mentioned array semiconductor laser pumped solid-state laser, an array semiconductor laser stack is formed by stacking a plurality of array semiconductor laser parts in the thickness direction, and accordingly, an array distributed index lens in which the same number of array distributed index lens parts are stacked. Replaced by stack.

[Operation] The lateral mode characteristics of the semiconductor laser pumped solid-state laser are determined by the shape of the optical pumping space in the solid-state laser element in the case of the end-face pumping method. Therefore, in order to obtain the fundamental transverse mode, it is desirable that the intensity distribution of the pumping light that has been narrowed down should be as close to a Gaussian distribution shape as possible to stably form a beam spot of a certain size in the solid-state laser element.

A semiconductor laser light with a large divergence angle is obtained by using a distributed index lens, which is an optical glass body having a refractive index distribution in which the refractive index gradually decreases from the central axis toward the outer peripheral surface, as an optical coupler of a semiconductor laser pumped solid-state laser. Can be easily collected. By utilizing the fact that the laser light from each stripe can be condensed by using this distributed index lens, the light emitted from each stripe of the array semiconductor laser is condensed by the array distributed index lens and no spherical aberration occurs. High-quality fundamental transverse mode light can be obtained by narrowing the total light into one beam spot with an aspherical lens and exciting the solid-state laser element. Further, by using an array semiconductor laser stack in which a plurality of array semiconductor lasers are stacked in the thickness direction and an array distributed index lens stack corresponding thereto, an even stronger excitation light intensity can be obtained.

[Examples] In order to further clarify the features and advantages of the present invention, a detailed description will be given below based on examples.

FIG. 1 is a schematic diagram of an array semiconductor laser pumped solid-state laser device that focuses array semiconductor laser light and pumps a solid-state laser element at an end face. As shown in FIG. 1, Nd: YAG was used as the solid-state laser element 4, and one end face was dichroic coated (Nd: YAG laser oscillation wavelength was 1064 nm for high reflection (HR), and array semiconductor laser light was 808 nm for high transmission (A).
R)), and using that surface as an excitation surface, a resonator is formed with the output mirror 5. Array semiconductor laser used 1
Is 20 active layer stripes 7 with a width of 100 μm, 500 μm
It consists of an array arranged at intervals. The distributed index lens eye 2 as a condensing lens array is composed of 20 distributed index lenses each having a width of 500 μm, and collects and collimates the light emitted from each of the 20 stripes. 20 laser beams are focused by the aspherical lens 3 and overlapped at one place to excite the Nd: YAG laser rod. In the array semiconductor laser-pumped solid-state laser device pumped in this manner, the array semiconductor laser light (wavelength 808 nm) output 5
The fundamental transverse mode oscillation of the Nd: YAG laser (wavelength 1064 nm) at W is obtained through the output mirror 5 at a high output of 1.5 W.

FIG. 2 is a schematic diagram of an array semiconductor laser pumped solid-state laser that collects the oscillation light of the array semiconductor laser stack and pumps the end face of the solid-state laser element. The array semiconductor laser stack 8 used is one in which two array semiconductor lasers 1 described in the embodiment of FIG. 1 are stacked at 300 μm intervals in the thickness direction. The array distributed index lens stack 9 as a condensing lens array has an array distributed index lens whose upper and lower central axis intervals are the same as those of the array semiconductor laser stack 8.
Two of them are overlapped with each other at 0 μm, and each of the emitted lights from 40 stripes is condensed and collimated. In the following, an array semiconductor laser (wavelength 808n
m) The fundamental transverse mode oscillation of the Nd: YAG laser (wavelength 1064 nm) at 10 W at output is obtained at high output of 3 W.

Although the Nd: YAG laser element is used as the solid-state laser element in the embodiments of the present invention, the solid-state laser element is not limited to this. Needless to say, an array semiconductor laser having a wavelength matched to the maximum absorption wavelength is used with the change of the solid-state laser element. Both surfaces of the lens and the polarizing beam splitter are coated with an antireflection coating at the array semiconductor laser wavelength. Furthermore, the number of stages of the array semiconductor laser stack and the array refractive index lens array stack in the second embodiment is not limited to two.

[Effects of the Invention] As described above, a semiconductor laser pumped solid-state laser having such a configuration as an optical coupler enables end-face pumping, which was difficult with an array semiconductor laser, and has high efficiency and high beam quality. A laser can be realized.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an array semiconductor laser pumped solid-state laser device that collects array semiconductor laser light and pumps a solid-state laser element at an end face, and FIG. 2 collects oscillation light of an array semiconductor laser stack and It is a schematic diagram of an array semiconductor laser pumped solid-state laser that pumps a laser element at an end face. In the figure. 1: Array semiconductor laser 2: Array distributed index lens 3: Aspherical lens 4: Solid-state laser device 5: Output mirror 6: Solid-state laser output light 7: Semiconductor laser active layer stripe 8: Array semiconductor laser stack 9: Array distribution Refractive index lens stack

Claims (2)

[Claims] 1. In an array semiconductor laser pumped solid-state laser device for condensing array semiconductor laser light and optically pumping a solid-state laser element, distributed index lenses are arranged corresponding to each stripe of the array semiconductor laser, and array semiconductor laser output is provided. And a lens array for condensing and collimating each of the collimated striped lights at one time and superimposing them on one place, and an aspherical lens used as a focusing lens for exciting the end face of the solid-state laser element. An array semiconductor laser pumped solid state laser device comprising an optical coupler comprising 2. The array semiconductor laser pumped solid-state laser device according to claim 1, wherein the array semiconductor laser section is an array semiconductor laser stack in which a plurality of array semiconductor lasers are stacked in the thickness direction, and the array distribution is accordingly arranged. An array semiconductor laser pumped solid-state laser device, characterized in that the same number of refractive index lens portions are replaced with an array distributed refractive index lens stack in which array distributed refractive index lenses are stacked.