JPH0415970A - Semiconductor laser exciting solid laser device - Google Patents

Abstract

PURPOSE:To prevent instable mode pattern by alternately forming first films, which reflect solid laser beams and transmit semiconductor laser beams, and second films, which have at least either functions of passing solid laser beams or reflecting semiconductor laser beams. CONSTITUTION:Since the reflection points of YAG laser beams are positioned at intervals of 1mm on three places of exciting faces 1d, two kinds of coatings should be positioned at intervals of 1mm, so two kinds of coatings are applied alternately at intervals of 1mm. To the parts (white part) corresponding to the reflection points of YAG laser beams and the focus points of semiconductor laser beams, high reflection coating, for the wavelength of YAG laser beams, and nonreflecting coating, for the wavelength of semiconductor laser beams, are applied, and to each section between reflection points (oblique line part), high reflection coating is applied to the wavelength of semiconductor laser beams. By the above constitution, the stability of mode pattern and the alignment with excellent accuracy can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-output semiconductor laser-excited solid-state laser device used for processing metals, semiconductors, ceramics, etc., or for medical purposes as a coagulator.

Conventional technology Traditionally, arc lamps, flash lamps, etc. have been used to excite solid-state laser devices. The equipment for heat dissipation had to be large. In recent years, with the development of high-power semiconductor lasers, they have come to be used as excitation light sources for solid-state lasers. Semiconductor lasers can match the wavelength to the absorption band of the solid-state laser medium, which not only greatly improves the excitation efficiency, but also does not absorb excess spectrum, so it does not generate heat, making it a highly efficient and compact semiconductor laser. A pumped solid-state laser device is obtained.

Conventionally, a YAG laser beam as a solid-state laser beam is reflected in a spiral manner on each polygonal columnar surface of a polygonal columnar Nd:YAG rod having three side surfaces that intersect with each other at 60 degrees, and the reflection points of each component surface are reflected. A side pumping method has been proposed in which the laser beam is pumped by an array type semiconductor laser.

A conventional side pump type semiconductor laser pumped solid-state laser device will be described below.

FIG. 4 is a perspective view showing the configuration of a conventional semiconductor laser pumped solid-state laser device. In FIG. 4, a side-pumping type semiconductor laser pumped solid-state laser device has a hexagonal column-shaped Nd:YAG rod 1 as a solid-state laser medium, and an array is arranged so as to face each other on three side surfaces that intersect with each other at 60 degrees. It consists of a type semiconductor laser 2, a fiber lens 3 for condensing light, and an external reflecting mirror 4. In the case of FIG. 4, the structures of the array type semiconductor laser 2 and the fiber lens 3 are also present on the other two sides, but they are omitted here because the drawing becomes complicated. This hexagonal columnar Nd:Y
As shown in the exploded view of FIG. 6, the AG rod 1 has a hexagonal cross section with sides of lengths 2 and 3.8 lengths arranged alternately.
It is a hexagonal prism with a height of 11- and has a reflection surface 1a and an output surface 1b on the top and bottom surfaces, which serve as internal reflection mirrors and are inclined at an angle .theta.=4 degrees with respect to the normal direction of both surfaces. YAG
As shown in Figure 5, the laser beam is a hexagonal columnar Nd:YA
Inside the G rod 1, the reflecting surface 1a, which is an internal reflecting mirror, and the external reflecting mirror 4 are used as resonators, and 3 of the Nd:YAG rod 1 is
By reflecting off the side surface 1c, a spiral optical path is drawn. 10 GRlN-8C are placed at 1-intervals for each reflection point (marked with a mark) on the three side surfaces 1c of the Nd:YAG rod 1.
Each beam from an arrayed semiconductor laser 2 consisting of an R-QW relay is focused and excited by a fiber lens 3. Furthermore, the reflecting surface 1a is a flat surface, and the output surface 1a has a reflectance of 99% or more for the wavelength of 1.06 μm of YAG laser light.
b is a flat surface that has a transmittance of 99% or more for this wavelength of 1.06 μm;
Hexagonal columnar Nd
: The side surface 1c of the YAG rod 1 has a reflectance of 99% or more for a wavelength of 1.06 μm and a reflectance of 0.05% for a wavelength of semiconductor laser light.
The coatings are applied so that each has a transmittance of 90% or more at 809 μm.

Problems to be Solved by the Invention However, in the above-mentioned conventional method in which the fiber lens 3 focuses the semiconductor laser beams from the array type semiconductor laser 2 onto the excitation surface IC, each semiconductor laser beam in the length direction of the fiber lens 3 is Because the light concentration is not sufficient,
As the excitation input of the semiconductor laser is increased, the YAG
The mode pattern of the laser beam is T EMoo ([ta
There is a phenomenon that the reflection point of the YAG laser beam on the excitation surface lc and the convergence point of the semiconductor laser beam are aligned, and the reflection point is determined on the excitation surface lc. There was a problem in that it was difficult to match accurately because there was no such thing.

The present invention solves the above-mentioned conventional problems, and provides a semiconductor laser excitation system that can prevent the mode pattern from becoming unstable due to the increase in the output power of the semiconductor laser, and can accurately focus the excitation light onto the reflection point of the YAG laser beam. The purpose of this invention is to provide a solid-state laser device.

Means for Solving the Problems In order to solve the above-mentioned problems, the semiconductor laser pumped solid-state laser device of the present invention provides a solid-state laser device excited by a semiconductor laser. A semiconductor laser-excited solid-state laser device in which array-type semiconductor lasers having an array corresponding to the reflection points of the solid-state laser light that draw an optical path are provided on all surfaces of the solid-state laser medium having the reflection points, the solid-state laser A first lens provided on a side surface of the solid-state laser medium having a light reflection point at a position corresponding to the reflection point to reflect the solid-state laser light and transmit the semiconductor laser light from the array type semiconductor laser. A film and a second film provided at a position between the reflection points and having at least one function of transmitting the solid-state laser light or reflecting the semiconductor laser light are formed alternately. It is something.

Effect With the above configuration, a second film having at least one function of transmitting the solid-state laser light or reflecting the semiconductor laser light is provided between the reflection points of the solid-state laser light, and the solid-state laser Reflection loss is caused to the light, and excitation loss is caused to the semiconductor laser light, so even if an array type semiconductor laser is used as the excitation source and the output is increased, it will not deviate from the mode pattern as in the past. Without this, a stable TEMoo mode can be obtained, the reflection point of the solid-state laser beam can be easily determined, and the excitation light of the semiconductor laser beam can be accurately matched with the reflection point of the solid-state laser beam.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the configuration of a semiconductor laser pumped solid-state laser device according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the pumping surface in FIG. 1. The basic structure is the same as that of the conventional example, so the same reference numerals are given and the explanation is omitted.
Here, the stripe coat excitation surface 1d will be explained. In FIGS. 1 and 2, YA is placed on the excitation surface 1d.
Since the reflection points of the G laser beam are located at intervals of ~1 mm, the two types of coatings are also applied alternately at intervals of 1 mm. The part (white part) corresponding to the reflection point of the YAG laser beam and the condensing point of the semiconductor laser beam is coated with HR (high reflection) coating for the wavelength of 1.06 μm of the YAG laser beam, and for the wavelength of the semiconductor laser beam. A for 0.809μm
R (non-reflection) coating is applied, and between each reflection point (shaded area), the wavelength 080 of the semiconductor laser light is applied.
HR (high reflection) coating is applied to 9 μm.

The width of each part is ~04-1 for the former (white part) and 04-1 for the latter (hatched part)
is ~0.6m. Two types of similar stripe-like coatings are applied to the excitation surface 1d at three locations.

FIG. 3 shows the input/output characteristics of this embodiment. In Figure 3, when the maximum input power of the semiconductor laser is 20W, the YAG output is 6.9W.
Stable TEM ao while providing laser output
Operation in mode was obtained.

In this example, the coating between the reflection points (shaded areas) on the excitation surface d was applied to the wavelength of the semiconductor laser light, which was 0809 μm.
Although HR (high reflection) coating was applied to the
A similar effect can be expected by applying an AR (anti-reflection) coating to the wavelength of 1.06 μm of the YAG laser beam, or an even greater effect can be expected if it is applied in both directions. In other words, between each reflection point of the YAG laser beam, there is either an AR (anti-reflection) coating for the YAG laser beam with a wavelength of 1.06 μm, or an HR (high reflection) coating for the wavelength of 0,809 μm of the semiconductor laser beam. Either one or both coatings are applied between each reflection point of the YAG laser beam to give a reflection loss to the wavelength of 1.06 μm of the YAG laser beam, and
A coating is applied to give an excitation loss to the wavelength of the semiconductor laser light of 0.8 H μm, thereby making it possible to obtain stable mode patterns and highly accurate alignment.

Effects of the Invention As described above, according to the present invention, the reflection of the solid-state laser beam is achieved by alternately applying two types of films, the first and the second, on the side surface of the solid-state laser medium having the reflection point of the solid-state laser beam. It is possible to prevent the conventional mode pattern from becoming unstable due to high output by adding loss to areas other than the point, and to accurately focus the excitation light of the semiconductor laser beam onto the reflection point of the solid-state laser beam. It is something that can be done.

In particular, it has great effects as a solid-state laser for processing, medical, and other applications that require high output.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of the semiconductor laser pumped solid-state laser device of the present invention, FIG. 2 is an explanatory diagram of the excitation plane in the semiconductor laser pumped solid-state laser device, and FIG. 3 is a diagram showing the structure of the semiconductor laser pumped solid-state laser device. Input/output characteristic diagram; FIG. 4 is a perspective view showing the configuration of a conventional semiconductor laser pumped solid-state laser device;
FIG. 5 is a diagram illustrating the optical path of a YAG laser beam within a conventional solid-state laser medium, and FIG. 6 is a developed view of the conventional solid-state laser medium. 1... Hexagonal columnar Nd: YAG rod, 1b... Strive coat excitation surface, 2... Array type semiconductor laser.

Claims (1)

[Claims] 1. The solid-state laser includes an array-type semiconductor laser having an array corresponding to the reflection points of solid-state laser light that traces a spiral optical path while reflecting from the side surfaces of the solid-state laser medium in a solid-state laser medium that is a columnar body with a polygonal cross section. A semiconductor laser-excited solid-state laser device provided on all surfaces of the medium having the reflection points, the solid-state laser device being provided on a side surface of the solid-state laser medium having the reflection points of the solid-state laser beam at positions corresponding to the reflection points. a first film that reflects the solid-state laser light and transmits the semiconductor laser light from the array type semiconductor laser; and a first film that is provided at a position between the reflection points and transmits the solid-state laser light; A semiconductor laser-excited solid-state laser device in which second films having at least one function of reflecting semiconductor laser light are alternately formed.