JPH0311681A - Semiconductor laser excitation solid-state laser apparatus - Google Patents

Abstract

PURPOSE:To easily process a reflecting face and a radiating face by a method wherein the reflecting face and the radiating face are formed at a protruding part which has been formed at an end part of a polygonal-pillar constituent face of a polygonal pillar-shaped rod. CONSTITUTION:Protrusions 5e and 5f whose cross section is a triangle are formed near both end faces of a polygonal pillar-shaped rod 5; a reflecting face 5a and a radiating face 5b which have an angle of inclination to a polygonal-pillar constituent face are formed at the protrusions; the radiating face 5b is processed to be a convex instead of an external reflecting mirror 7. Thereby, the reflecting face 5a and the radiating face 5b which have been formed at a polygonal pillar-shaped solid-state laser medium can be processed easily; as a result, a convex spherical face of the radiating face 5b can be processed; it is possible to obtain an apparatus which is not provided with the external reflecting mirror, which is subminiature, whose output is high and whose cost is low.

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.

(Prior art) Conventionally, arc lamps, flash lamps, etc. have been used to excite solid-state laser devices, but due to low excitation efficiency, the efficiency of the entire laser is poor, and the heat dissipation of the lamp and solid-state laser medium is poor. Therefore, the device had to be large. In recent years, with the development of high-power semiconductor lasers,
This has come to be used as an excitation light source for solid-state lasers.

Among them, the method of axially exciting the axial end face of the Nd:YAG laser medium with a semiconductor laser is a method that can efficiently and stably generate T E of W.
It is attracting attention as a method of oscillating in Mo mode.

A conventional semiconductor laser-excited solid-state laser device of this type will be explained with reference to FIG. In the same figure, a conventional semiconductor laser pumped solid-state laser device has a structure in which a Nd:YAG rod 1 injected with neodymium (Nd) is sandwiched between the Nd:YAG
A YAG laser in which an optical resonator is formed by a planar internal reflecting mirror formed on the rear end surface of the AG rod 1 and a concave external reflecting mirror 2; a semiconductor laser 3 that excites the Nd:YAG rod 1; The emitted light of the semiconductor laser 3 is
: Consisting of a condensing lens 4 that condenses light onto the rear end surface of the YAG lot 1.

The output light of the semiconductor laser 3 is converted into Nd:YAG by the condenser lens 4.
The method of exciting the YAG laser by focusing light on the axial end face of the rod 1 not only has high excitation efficiency, but also has high coupling efficiency between the semiconductor laser light and the YAG laser light due to axial excitation.
It works stably in TEMoo mode, but only one excitation point
Moreover, since there is a limit to increasing the output of the semiconductor laser 3, there is a problem in that it is difficult to increase the output of the YAG laser.

As a solution to this problem, the inventors proposed the method shown in FIG.

Polygonal columnar Nd:YAG as shown in Figures 6 and 7
We have proposed a side excitation method in which the YAG laser beam is reflected in a spiral shape on each polygonal prism surface of the rod 1, and the reflection points (marked with *) on each surface are excited by a plurality of semiconductor lasers.

A side-pumping type semiconductor laser-pumped solid-state laser device proposed by the inventor will be described. FIG. 5 is a perspective view showing the configuration of a semiconductor laser pumped solid-state laser device by the present inventor, FIG. 6 is a perspective view showing the solid-state laser section, FIG. 7 is a developed view of the solid-state laser medium, and FIG. It is an output characteristic diagram.

In FIG. 5, the semiconductor laser-excited solid-state laser device according to the present invention has a hexagonal prism shape with a width of 5 m on the negative side and a length of 32 m, and has an interior with an angle O of 11° with respect to the central axis at the center of both end faces. The Nd:YA, G rod 5 has a reflecting surface 5a serving as a reflecting mirror and an output surface 5b, and the YAG rod 5 moves from the reflecting surface 5a to the output surface 5b while repeating internal reflection, as shown by the broken line in FIG. A plurality of lens-integrated semiconductor lasers 6 are arranged to face each of the constituent surfaces 5d of the hexagonal prism in accordance with each reflection point 5C of the laser beam, and a concave surface side is arranged to face each of the constituent surfaces 5d of the hexagonal prism, and a concave surface side is arranged so as to face the emission surface 5b. It consists of an external reflecting mirror 7 with a radius of curvature of 1 m. Furthermore, the reflectance and transmittance of these components are determined by Nd:Y
The reflective surface 5a of the AG rod 5 has a reflectance of 99% or more for a wavelength of 1.06 m, and its output surface 5b has a reflectance of 1.0 m for the same wavelength.
Transmittance of 99% for 6 houses, whose hexagonal prism constituent surface 5d is the wavelength], Reflectance of 99% or more for 067 m and transmission of 90% or more for wavelength 0.809 μm The coating was applied so that the concave mirror surface of the external reflecting mirror 7 had a reflectance of 80% for a wavelength of 1.06 mm.

As a result, as shown in the output characteristic diagram of FIG. 8, the oscillation threshold input value of the lens-integrated semiconductor laser 6 for the semiconductor laser pumped solid-state laser device proposed by the inventor to oscillate is 0.9W, the maximum. Output is 3.2W when input value is IOW
Met. Note that the output per lens-integrated semiconductor laser 6 at this time is 0.28W.

(Problems to be Solved by the Invention) The above-mentioned side-pumping type semiconductor laser pumped solid-state laser device proposed by the inventor uses semiconductor laser light and YAG laser light, similar to the conventional axial-pumping type solid-state laser device shown in FIG. Not only is the excitation efficiency high because of the good coupling efficiency of T E M
, , mode, and is excited by a large number of lens-integrated semiconductor lasers 6, a high-output semiconductor laser pumped solid-state laser device can be obtained. However, since the end faces of the hexagonal columnar Nd:YAG rod 5 are processed to form the reflective surface 5a and the output surface 5b that protrude from both end faces, it is easy to process them into a flat surface, but it is difficult to process them into a spherical surface. The problem was that it was difficult.

Therefore, it is necessary to make the output surface 5b a flat surface and provide an external reflecting mirror 7, which poses a problem in that it is difficult to further downsize the device.

The present invention solves the above problems and provides an ultra-small, high-output semiconductor laser pumped solid-state laser device without an external reflecting mirror.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides hexagonal columnar Nd:
A reflecting surface and an emitting surface are formed on the protrusion provided at the end of the hexagonal prism-constituting surface of the YAG rod.

(Function) With the above configuration, the processing of the reflection surface and the emission surface is not hindered by the end face, so it becomes easy. Therefore, since the exit surface can be easily processed into a spherical surface, an external reflecting mirror can be omitted, and further miniaturization can be achieved.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1, FIG. 2, and FIG. 3 are perspective views showing the configuration of a semiconductor laser pumped solid-state laser device according to the present invention, respectively;
FIG. 2 is a perspective view of the solid-state laser section and a developed view of the solid-state laser medium.

The difference between the embodiments shown in these figures and the examples proposed by the inventors shown in FIGS. 5 to 8 is that the hexagonal columnar Nd:YAG
Protrusions 5e and 5f with a triangular cross section are formed near both end faces of the rod 5, and a reflecting surface 5a and an output surface 5b are provided thereon, forming an inclination angle O of 11° with the axial center line, and an external reflecting mirror 7. Instead, the output surface 5b is processed into a convex surface with a radius of curvature of 1 m, and coated to have a reflectance of 80% for a wavelength of 1.067 m. Since the other components are the same, the same components are given the same reference numerals and their explanations will be omitted.

Furthermore, since its operation and output characteristics are the same as those proposed by the inventor, their explanation will be omitted.

Although the hexagonal columnar Nd:YAG rod 5 is used in the present invention, the number of angles may be increased, and the number of lens-integrated semiconductor lasers installed facing each component surface may be increased. Also,
Although a condensing lens is integrated, an optical fiber may be used to excite the reflection point 5C.

(Effects of the Invention) As explained above, according to the present invention, it is extremely easy to process the reflection surface and the emission surface formed on the polygonal columnar solid-state laser medium, so it is possible to process the emission surface into a convex spherical surface.
An ultra-small, high-output, and inexpensive semiconductor laser-excited solid-state laser device without an external reflecting mirror can be obtained. Therefore, it greatly contributes to processing and medical applications that require high output.

[Brief explanation of drawings]

1, 2, and 3 are perspective views showing the configuration of a side-pumped type semiconductor laser pumped solid-state laser device according to the present invention, a perspective view of its hexagonal columnar Nd:YAG rod, and a developed view thereof, and FIG. 4. 7 is a perspective view of a conventional axially pumped semiconductor laser pumped solid-state laser device, and FIGS. 5, 6, 7, and 8 are side-pumped semiconductor laser pumped solid-state laser devices proposed by the inventor A perspective view showing the configuration, a perspective view of the solid-state laser part,
FIG. 2 is a developed diagram and an output characteristic diagram of the solid-state laser medium. 1 ・Nd:YAG rod, 2, 7 ... external reflecting mirror, 3 ... semiconductor laser, 4 ... condensing lens, 5 ... hexagonal columnar Nd:YAG rod, 5a...
・Reflection surface, 5b... Output surface, 5c... Reflection point,
5d...Hexagonal prism configuration surface, 5e, 5f...Protrusion,
6...Lens integrated semiconductor laser.

Claims (1)

[Claims] It has a polygonal column shape, and a reflecting surface and an output surface having an inclination angle with the polygonal column forming surfaces are formed on protrusions provided on the polygonal column forming surfaces near both ends, and the reflecting surface is a flat surface and the output surface is a plane. A semiconductor laser-excited solid-state laser device comprising a solid-state laser medium with an optical resonator configured as a convex spherical surface, and a plurality of semiconductor lasers arranged so as to focus light on a spiral reflection point of the polygonal prism configuration surface. .