JP2006093386A - Laser oscillation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit the manufacture of a miniaturized and inexpensive laser oscillation device, high in the output thereof compared with a conventional device, and oscillating a plurality of kinds of laser beams, since a plurality of dope units 3, 4 are provided in one non-dope unit 2. <P>SOLUTION: The laser oscillation device is provided with a laser crystal 1 equipped with a plurality of dope units 3, 4 in the non-dope unit 2 while the plurality of dope units 3, 4 are arranged in one set of resonator optical path 11. In another way, a plurality of resonator optical paths are provided and at least one dope unit is arranged in each resonator optical path. These dope units can be units for exciting laser beams of the same wavelength or can be units for exciting at least two kinds of laser beams having wavelengths different from each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser oscillation device, and more particularly to a laser oscillation device including a laser crystal.

Conventionally, as a laser oscillation apparatus equipped with a laser crystal, a laser crystal provided with a doped portion therein, excitation light irradiation means for exciting the doped portion by irradiating the laser crystal with excitation light, and oscillation from the doped portion There is known a laser beam path including a resonator optical path for resonating the laser beam between a front mirror and a rear mirror and emitting the laser beam from the front mirror.
When the output is increased in this type of laser oscillation device, a plurality of laser crystals are provided, and one resonator optical path is provided in common to the plurality of laser crystals (Patent Document 1).
JP 2004-172534 A

When a plurality of laser crystals are provided in order to increase the output, each laser crystal needs to be provided with an excitation light irradiation means, so that there is a disadvantage that the entire apparatus becomes expensive and becomes large.
Furthermore, for example, when two types of laser beams having different wavelengths are required, two types of laser crystals capable of oscillating laser beams of the respective wavelengths must be prepared, and the entire apparatus is also expensive and large. There was a drawback.
In view of such circumstances, the present invention can provide a small-sized laser oscillation device with a large output or a small-sized laser oscillation device capable of oscillating laser beams of a plurality of wavelengths at low cost. is there.

The invention of claim 1 includes a laser crystal having a doped portion therein, excitation light irradiation means for irradiating the laser crystal with excitation light to excite the doped portion, and laser light oscillated from the doped portion. In a laser oscillation device including a resonator optical path that resonates between a front mirror and a rear mirror and emits the light from the front mirror,
A laser oscillation device is provided, wherein a plurality of doped portions are provided in the laser crystal, and a plurality of doped portions are arranged in at least one resonator optical path.
Even if the plurality of doped portions oscillate laser beams having the same wavelength as described in the invention of claim 4, at least two kinds of doped portions are provided as described in the invention of claim 5. May oscillate laser beams having different wavelengths.

According to a second aspect of the present invention, there is provided a laser crystal provided with a doped portion therein, excitation light irradiation means for irradiating the laser crystal with excitation light to excite the doped portion, and laser light oscillated from the doped portion. In a laser oscillation device including a resonator optical path that resonates between a front mirror and a rear mirror and emits the light from the front mirror,
Provided is a laser oscillation device characterized in that a plurality of doped portions are provided in the laser crystal, a plurality of the resonator optical paths are provided, and at least one doped portion is disposed in each resonator optical path. .
Even if the plurality of doped portions oscillate laser beams having the same wavelength as described in the invention of claim 4, at least two kinds of doped portions are provided as described in the invention of claim 5. May oscillate laser beams having different wavelengths.

In the first aspect of the present invention, since a plurality of doped portions are provided in the laser crystal and a plurality of doped portions are disposed in at least one resonator optical path, the number of doped portions is one inside the laser crystal as in the prior art. Compared with the case where two doped portions are provided, and a plurality of such laser crystals are provided, it is possible to manufacture at a low cost and in a small size.
When the plurality of doped portions oscillate laser beams having the same wavelength as described in claim 4, the output can be increased by the plurality of doped portions. On the other hand, when the plurality of doped portions oscillate laser beams having different wavelengths as described in claim 5, the laser beams having different wavelengths can be oscillated by the plurality of doped portions. .

In the invention of claim 2, since a plurality of doped portions are provided in the laser crystal, a plurality of the resonator optical paths are provided, and at least one doped portion is disposed in each resonator optical path. The laser light can be oscillated by each device. Therefore, when a plurality of laser beams are required, a single doped portion is provided inside a single laser crystal as in the prior art, and it can be manufactured at a lower cost and smaller than when a plurality of such laser crystals are provided. It becomes possible.
If the plurality of doped portions oscillate laser beams having the same wavelength as described in claim 4, a plurality of laser beams having the same wavelength can be oscillated, When the plurality of doped portions oscillate laser beams having different wavelengths as described in claim 5, laser beams having different wavelengths can be oscillated by the plurality of doped portions.

The present invention will be described below with reference to the illustrated embodiments. In FIGS. 1 and 2, the laser crystal 1 is composed of a laser mother crystal having a thin plate shape and a circular cross section, and a plurality of the same wavelengths are used in the illustrated embodiment. Two doped portions 3 and 4 to which laser active ions capable of oscillating the laser beam are added. These two doped portions 3 and 4 are respectively provided in the thickness direction of the laser crystal 1, and in the illustrated embodiment, each doped portion 3 and 4 reaches them between the upper surface and the lower surface of the laser crystal 1. However, it is not always necessary to reach the upper surface or the lower surface. A portion other than the doped portion of the laser crystal is defined as an undoped portion 2.
As shown in FIG. 2, the laser crystal 1 is placed in close contact with the upper surface of a cooling means 5 such as a heat sink, and is cooled by the cooling means 5. It is desirable to provide the dope portions 3 and 4 apart from the point of the cooling effect.

Outside the side portion of the laser crystal 1, excitation light irradiation means 6 for irradiating the laser crystal 1 with excitation light and exciting the doped portions 3 and 4 is provided. In the illustrated embodiment, the excitation light irradiation means 6 includes a semiconductor laser array 7 in which semiconductor lasers are arranged in a line, and the longitudinal direction of the semiconductor laser array 7, that is, the arrangement direction of the semiconductor laser in a line is The first laser light is arranged in a direction perpendicular to the radial direction of the circular laser crystal 1, and the direction of the first axis of the semiconductor laser light, which is excitation light, is the thickness direction of the laser crystal.
A rod lens 8 is integrally provided on the light emitting portion side of the semiconductor laser array 7, and the excitation light emitted from the semiconductor laser array 7 has a first axis direction substantially equal to the thickness of the laser crystal by the rod lens 8. The light is condensed to the extent that it can be irradiated onto the doped portions 3 and 4. Instead of providing the rod lens 8, a condenser lens may be provided between the semiconductor laser array 7 and the laser crystal 1.
The slow axis direction of the semiconductor laser light is condensed by passing through the circular outer peripheral surface of the laser crystal 1 so that the width of the excitation light substantially coincides with the combined width of the doped portions 3 and 4. On the outer peripheral surface of the laser crystal 1, there is provided a reflective film 9 that allows transmission of excitation light from the outside to the inside but does not allow transmission from the inside to the outside but totally reflects it. In this way, if the cross section of the pumping light is matched to the side shape of the doped parts 3 and 4 and most of the pumping light is absorbed in one pass with respect to the doped parts 3 and 4, the pumping efficiency is very high. It is possible to perform good laser oscillation. In addition, you may provide the said excitation light irradiation means 6 in multiple numbers outside the side part of the laser crystal 1 as needed.

Next, in this embodiment, one resonator optical path 11 is provided, and the two doped portions 3 and 4 are arranged in series in this one resonator optical path 11. That is, the resonator optical path 11 includes a front mirror 12, a rear mirror 13, a reflection mirror 14, and a reflection film 15. The reflection film 15 is formed between the lower surface of the laser crystal 1 and the upper surface of the cooling means 5. It is provided in between so that the laser beam L can be totally reflected.
Accordingly, the laser light L oscillated from the two doped portions 3 and 4 is reflected by the front mirror 12 and is also rear-mirrored through the doped portion 3, the reflective film 15, the reflective mirror 14, the doped portion 4 and the reflective film 15. 13, and is resonated between the front mirror 12 and the rear mirror 13, and finally emitted from the front mirror 12 to the outside.

In the above embodiment, if the laser light is emitted from the excitation light irradiation means 6 to the laser crystal 1 and the dope portions 3 and 4 oscillate the laser light, the laser light L is transmitted through the resonator optical path 11 as described above. Resonated and eventually emitted from the front mirror 12 to the outside.
In the above embodiment, two doped portions 3 and 4 that can oscillate laser light of the same wavelength are provided in one laser crystal 1, and thus one doped portion is provided in one laser crystal. The output can be increased as compared with the conventional apparatus. On the other hand, as compared with the conventional apparatus in which two laser oscillators each having one doped portion provided in one laser crystal are arranged in series to increase the output, the entire apparatus can be reduced in size.

In the above-described embodiment, the two doped portions 3 and 4 oscillate the laser light L having the same wavelength. However, the present invention is not limited to this, and laser active ions added to the respective doped portions. May be used to oscillate laser beams having different wavelengths.
More specifically, the doped portions 3 and 4 can be set to oscillate laser beams having different wavelengths. In this case, the laser beam L extracted from the front mirror 12 is a laser beam including two types of wavelengths. In this case, it is preferable that two excitation light irradiation means 6 are provided so that excitation light having a suitable wavelength suitable for the absorption wavelength of each of the doped portions 3 and 4 can be irradiated. As long as each dope part 3 and 4 can be excited by the excitation light from the light irradiation means 6, the single excitation light irradiation means 6 may be sufficient.
Even when the doped portions 3 and 4 are set to oscillate laser light L of the same wavelength, or are set to oscillate laser light of different wavelengths, the doped portion is not limited to two. And more can be provided. In this case, the number of doped portions that oscillate laser light L having the same wavelength and the number of doped portions that oscillate laser light having different wavelengths can be set as appropriate.

Next, FIGS. 3 and 4 show a second embodiment of the present invention. In this embodiment, one laser crystal 21 is provided with four doped portions 22, 23, 24, and 25. FIG. These four doped portions 22 to 25 can oscillate laser beams having the same wavelength, and the four doped portions 22 to 25 are arranged in one resonator optical path 26.
For this purpose, the resonator optical path 26 is provided with three reflecting mirrors 29, 30, 31 between the front mirror 27 and the rear mirror 28, and the laser light L oscillated by the respective doped portions 22-25 is Between the front mirror 27 and the rear mirror 28, a reflection film (not shown), a reflection mirror 29, a doping part 23, the reflection film, a reflection mirror 30, a doping part 24, and the like provided on the lower surface of the doped part 22 and the laser crystal 21. Resonance can be achieved through the reflective film, the reflective mirror 31, the doped portion 25, and the reflective film.

In the present embodiment, excitation light irradiation means 35 and 36 each having a semiconductor laser array 33 and a rod lens 34 are provided at two positions facing each other outside the side of the laser crystal 21. Excitation light from the excitation light irradiating means 35 and 36 can be applied to the respective doped portions 22 to 25 while being condensed by the rod lens 34.
At this time, the outer peripheral surface of the laser crystal 21 is formed in a lens shape 21a, and the excitation light from the excitation light irradiation means 35 and 36 is condensed by the lens shape 21a, respectively. The width of light is set to a width that just includes the entire doped portions 22 to 25. In the illustrated embodiment, the lens shape 21a on the outer peripheral surface of the laser crystal 21 is formed in an arc shape that is convex toward the central portion in the longitudinal direction of the semiconductor laser array 33. The excitation light from the irradiation means 35 and 36 can be condensed on the entire dope portions 22 to 25. The lens shape 21a is not limited to an arc shape that is convex toward the central portion in the longitudinal direction of the semiconductor laser array 33, and may have any shape as long as it has a light condensing function.
Although not shown, it is needless to say that this embodiment also includes a cooling means and a reflective film 9 as in the above-described embodiments.
Even with such a configuration, it is clear that a laser output device having a large output can be manufactured in a smaller size and at a lower cost than a conventional device.

Also in the second embodiment, the four doped portions 22 to 25 oscillate the laser light L having the same wavelength, but the present invention is not limited to this.
More specifically, all the doped portions 22 to 25 may be set as doped portions that oscillate laser beams having different wavelengths, or two doped portions oscillate laser beams having the same wavelength, for example. You may make it obtain the laser beam of 2 types of wavelengths as a dope part.
Also in this embodiment, the number of the doped portions 22 to 25 is limited to four, whether they are set to oscillate laser beams of the same wavelength or to oscillate laser beams of different wavelengths. In this case, an appropriate number of doped portions can be provided, and the number of doped portions that oscillate laser light having a different wavelength from the number of doped portions that oscillate laser light having the same wavelength is set appropriately. Of course you can.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, one laser crystal 41 is provided with four doped portions 42, 43, 44, 45. These four doped portions 42 to 45 can oscillate laser beams of the same wavelength, and two resonator optical paths 46A and 46B are provided for the four doped portions 42 to 45. Yes.
One resonator optical path 46A includes a front mirror 47A, a rear mirror 48A, and a reflection mirror 49A, and two doped portions 42 and 43 are arranged in series in the resonator optical path 46A. Therefore, in this resonator optical path 46A, the laser light L excited by the respective doped portions 42 and 43 is provided between the front mirror 47A and the rear mirror 48A on the lower surface of the doped portion 42 and the laser crystal 41 (not shown). Resonance can be achieved through the reflective film, the reflective mirror 49A, the doped portion 43, and the reflective film.

In contrast to the one resonator optical path 46A, the other resonator optical path 46B includes a front mirror 47B, a rear mirror 48B, and a reflection mirror 49B, and two doped portions 44 and 45 are connected in series to the resonator optical path 46B. It is arranged in. Therefore, in the resonator optical path 46B, the laser light L excited by the respective doped portions 44 and 45 is provided between the front mirror 47B and the rear mirror 48B on the lower surface of the doped portion 44 and the laser crystal 41 (not shown). Resonance can be achieved through the reflective film, the reflective mirror 49B, the doped portion 45, and the reflective film.
Although not shown, it is a matter of course that this embodiment also includes a cooling means, a reflective film, or an excitation light irradiation means, as in the above-described embodiments.

  According to the third embodiment, two laser beams L having the same wavelength can be extracted by one laser crystal 41. Therefore, when two laser beams L having the same wavelength are required, it is obvious that the laser beam L can be manufactured in a small size and at a lower cost than when two laser oscillation devices are separately provided.

In the third embodiment, the plurality of doped portions oscillate laser beams L having the same wavelength. However, the present invention is not limited to this, and oscillates laser beams having different wavelengths. It may be.
For example, in the third embodiment, the doped portions 42 and 43 in one resonator optical path 46A are doped portions that oscillate laser beams having the same wavelength, and the doped portions 44 and 45 in the other resonator optical path 46B are also included. The doped portions that oscillate laser beams having the same wavelength can be used, and the doped portions 42 and 43 and the doped portions 44 and 45 can be doped portions that oscillate laser beams having different wavelengths.
Alternatively, for each of the resonator optical paths 46A and 46B, the doped portions 42 (44) and the doped portions 43 (45) may be doped portions that oscillate laser beams having different wavelengths.

  As understood from the above description, in the present invention, a plurality of doped portions may be provided inside one laser crystal, and a plurality of doped portions may be arranged in at least one resonator optical path, or A plurality of doped portions may be provided inside one laser crystal, a plurality of the resonator optical paths may be provided, and at least one doped portion may be disposed in each resonator optical path.

The top view which shows 1st Example of this invention. The side view of FIG. The top view which shows 2nd Example of this invention. The perspective view of the principal part of FIG. The perspective view which shows 3rd Example of this invention.

Explanation of symbols

1, 21, 41 Laser crystal 2 Undoped part 3, 4, 22-25, 42-45 Doped part 5 Cooling means 6, 35, 36 Excitation light irradiation means 7, 33 Semiconductor laser array 11, 26, 46A, 46B Resonance Optical path 12, 27, 47A, 47B Front mirror 13, 28, 48A, 48B Rear mirror 14, 29-31, 49A, 49B Reflective mirror 21a Lens shape

Claims (8)

A laser crystal having a doped portion therein; excitation light irradiation means for irradiating the laser crystal with excitation light to excite the doped portion; and laser light oscillated from the doped portion between the front mirror and the rear mirror. In a laser oscillation device comprising a resonator optical path that resonates with and emits from a front mirror,
A laser oscillation apparatus comprising: a plurality of doped portions provided in the laser crystal; and a plurality of doped portions disposed in at least one resonator optical path. A laser crystal having a doped portion therein; excitation light irradiation means for irradiating the laser crystal with excitation light to excite the doped portion; and laser light oscillated from the doped portion between the front mirror and the rear mirror. In a laser oscillation device comprising a resonator optical path that resonates with and emits from a front mirror,
A laser oscillation device comprising a plurality of doped portions in the laser crystal, a plurality of the resonator optical paths, and at least one doped portion disposed in each resonator optical path.   3. The laser oscillation apparatus according to claim 2, wherein a plurality of doped portions are arranged in at least one resonator optical path.   4. The laser oscillation apparatus according to claim 1, wherein the plurality of doped portions excite laser light having the same wavelength.   4. The laser oscillation apparatus according to claim 1, wherein the plurality of doped portions excite at least two types of laser beams having different wavelengths.   A plurality of the excitation light irradiation means are provided, and each excitation light irradiation means can irradiate a suitable excitation light to each of the dope portions that oscillate laser beams having different wavelengths. The laser oscillation device according to claim 5.   The laser crystal is formed in a thin plate shape, and a plurality of doped portions are respectively provided in the thickness direction of the laser crystal, and excitation light from the excitation light irradiation means is incident from the outer peripheral surface of the laser crystal. The laser oscillation device according to any one of claims 1 to 6. 8. The laser oscillation apparatus according to claim 1, wherein the excitation light irradiation means is a semiconductor laser array in which semiconductor lasers are arranged in a line.

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