JPH0747891Y2 - Solid-state laser device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an optically pumped solid-state laser for use as a light source for measurement, etc., in which a semiconductor laser or parallel light having linearly polarized light is used as an excitation light source for laser oscillation. The present invention relates to a solid-state laser device used.

[Prior Art] Conventionally, a solid-state laser device has been known as a laser light source that can easily obtain an oscillation output, has a simple device structure, or has excellent spectrum monochromaticity and a small wavelength shift due to temperature. There is. In such a solid-state laser device, a laser rod made of YAG crystal or glass doped with active ions, a light source such as a xenon lamp, and the outer circumference of the laser rod are covered, and the excitation light emitted from the light source is reflected. A highly accurate elliptic cylindrical condenser for intensively irradiating the laser rod, a cooling mechanism for preventing overheating, and the like are used.

Further, a so-called semiconductor laser pumped solid-state laser in which a condenser and a cooling mechanism can be omitted by making laser light amplified in an optical resonator enter in the longitudinal direction from both end faces of the laser rod has been devised. There is.

[Problems to be Solved by the Invention] However, in a solid-state laser excited by a xenon lamp or the like, a condenser and a cooling mechanism for preventing overheating are required, so that the device becomes large. Further, in a semiconductor laser pumped solid-state laser in which pumping light is incident in the longitudinal direction of the laser rod, there is a limit to the arrangement that can efficiently guide the pumping light to the laser rod, so the pumping light amount cannot be increased,
The emitted laser light was weak.

[Object of the Invention] The present invention has been made in order to solve the above-described problems, and is achieved by combining a polarization beam splitter with a solid-state laser device that emits excitation light from both directions of a laser rod. It is an object of the present invention to provide a solid-state laser having a simple structure, a small size, and a large output.

[Means for Solving the Problems] In order to achieve this object, the solid-state laser device of the present invention is
It includes a laser rod, an optical resonator that bidirectionally excites the laser rod in the longitudinal direction, and a polarization beam splitter that synthesizes a set of laser beams whose polarization planes intersect at right angles into a single beam.

[Operation] In the present invention having the above configuration, the laser rod emits fluorescence peculiar to the element contained in the laser rod when the excitation light of a specific wavelength enters. A semiconductor laser or linearly polarized parallel light is used as excitation light for the laser rod,
A pair of lights whose polarization directions are orthogonal to each other are combined into one by a polarization beam splitter. The optical resonator amplifies this fluorescence and emits it as laser light having a uniform phase.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of a polarization beam splitter (hereinafter referred to as PBS) 20. As is well known, PBS20 has a shape in which two right-angle prisms are optically laminated. For example, when light 10a polarized in the direction perpendicular to the paper surface is incident on PBS20, it is reflected by the bonding surface and is parallel to the paper surface. Transmits when 10 is incident.

FIG. 2 shows an example of a solid-state laser device.

In the illustrated embodiment, a fiber shaped laser rod is used. This fiber 100 is, for example, a normal glass fiber doped with neodymium or a YAG crystal doped with neodymium with a core diameter of 4
Those processed into a fiber shape of about 6 μm can be suitably used. A resonant mirror 130 that transmits light having a wavelength of 810 nm and reflects 100% of light having a wavelength of 1064 nm is closely attached to one end of the fiber 100. The other resonant mirror 330
Is arranged between the other end of the fiber 100 and a convex lens 320 and a half mirror 310.
It reflects 100% of 0 nm light and 90% of 1064 nm light. The half mirror 310 transmits 810 nm light and transmits 1064 nm light to 10
0% reflection. 4 semiconductor lasers 200a, 200b, 200c, 2
The oscillation wavelength of 00d is 810 nm, and the polarization directions of the two semiconductor lasers 200b and 200c are parallel to the bonding planes of the PBS 230 and 300, and the other two semiconductor lasers 200a and 200c.
It is arranged so that the polarization direction of 0d is orthogonal to this.
This semiconductor laser 200a, 200b, 200c, 200d and PBS 230, 30
Between 0, four collimator lenses 210a, 210b, 210c and 210d for shaping the laser light into parallel light are respectively arranged, and between the PBS 230 and the resonance mirror 130, a convex lens 2 is provided.
20 are arranged.

In the configuration as described above, the semiconductor laser 20
The light emitted from 0a, 200b, 200c, and 200d is collimated by collimator lenses 210a, 210b, 210c, and 210d, and then PBS2.
It is incident on 30 and 300 respectively. Light from the semiconductor lasers 200b and 200c whose polarization directions are parallel to the bonding planes of the PBS230 and 300 is reflected by the PBS230 and 300, respectively, and light from the semiconductor lasers 200a and 200d whose polarization direction is perpendicular to this is PBS230 and 300.
Through. Therefore, the lights from the two semiconductor lasers 200a and 200b are combined by the PBS 230, and the lights from the two semiconductor lasers 200c and 200d are combined by the PBS 300. The light combined in this way is that the light from one PBS 230 is converged by the convex lens 220, then passes through the resonance mirror 130 and enters the fiber 100. The light from the other PBS 300 passes through the half mirror 310 and then enters the fiber 100 by the convex lens 320. Neodymium in the fiber 100 is photoexcited by this semiconductor laser light, and fluorescence of about 1064 nm is emitted.
This fluorescence is amplified by the two resonance mirrors 130 and 330, and a part thereof is emitted from one resonance mirror 330. At this time, the laser output can be increased by increasing the amount of pumping light by the above configuration, because when the amount of pumping light exceeds the threshold value of laser oscillation, the increase in amount of pumping light is proportional to the increase in output.

[Effects of the Invention] As is clear from the above description, according to the present invention, by using the polarization beam splitter, the light beams whose polarization directions are orthogonal to each other from one set of excitation light sources are converted into one light beam. Since they can be combined, all of the incident light can be used without loss, and the amount of excitation light can be increased with a simple configuration.

[Brief description of drawings]

1 to 2 show an embodiment embodying the present invention, FIG. 1 is an explanatory view of a polarization beam splitter, and FIG. 2 is a perspective view showing a solid-state laser device of the present invention. Is. 20 (230, 300) is a polarization beam splitter, 100 is a fiber, 130 and 330 are resonant mirrors, and 200a, 200b, 200c and 200d are semiconductor lasers.

Claims (1)

[Scope of utility model registration request] 1. A solid-state laser device using a plurality of semiconductor lasers or parallel light having linearly polarized light as an excitation light source for laser oscillation, comprising a polarizing beam splitter formed by laminating two right-angled prisms, and With respect to the beam splitter, a pair of excitation light sources in which the polarization directions of the lights are orthogonal to each other, the light emitted from one of the excitation light sources passes through the polarization beam splitter, and the light emitted from the other is transmitted by the polarization beam splitter. A solid-state laser device, which is arranged so as to be reflected so that lights emitted from respective pumping light sources and having polarization directions orthogonal to each other can be combined into one light by the polarization beam splitter.