JP3163779B2 - Laser equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser device used in an optical information processing field or an optical applied measurement control field.

[0002]

2. Description of the Related Art The use of a semiconductor laser as an excitation light source for a solid-state laser to obtain near-infrared light and the obtaining of green and blue light sources by high-efficiency wavelength conversion using a non-linear crystal are required in the field of optical information processing and optical applied measurement. It is required in the control field and the like. In particular, a light source having a short wavelength is required for high-density recording of an optical disc, image processing, and the like. The output light obtained here is Gaussian in transverse mode and can be focused to near the diffraction limit.
It is necessary that a single longitudinal mode be used, and that the output be about several mW and be stable both in frequency and time.

In order to obtain a stable near-infrared light or short-wavelength light source using a semiconductor laser as an excitation light source, a semiconductor laser excitation solid-state laser or an internal resonator type in which a wavelength conversion element is inserted inside a resonator to obtain a harmonic. Solid lasers are influential.

FIG. 5 shows a schematic configuration diagram of an internal cavity type short wavelength light source of a semiconductor laser pumped solid laser. Light emitted from the semiconductor laser 501 is converted into a parallel beam by a collimating lens 502, and a laser material (for example, Nd: YVO ₄ ) 504 is focused by a focusing lens 503.
Is collected. Incident side end surface 505 of laser material 504
Has an anti-reflection (AR) coating for the wavelength (809 nm) of the semiconductor laser, and a high reflection (HR) coating for the oscillation wavelength (1.064 μm) and the harmonic wavelength (532 nm). The end face 506 has 1.
AR coating is applied to 064 μm and 532 nm. The output mirror 507 is coated with a reflectance of 97% for a wavelength of 1.064 μm, and the output mirror 507 and the end face 505 of the laser material 504 constitute a resonator having a fundamental wave of 1.064 μm. The resonator length is 50 mm.

In the conventional resonator structure, the output mirror 5 shown in FIG.
Reference numeral 07 is fixed to the output mirror holder 601 as shown in FIG. 6, and a micrometer 603 is attached to the rear part of the mirror holder 601. By linearly moving the micrometer 603, the output mirror 602 becomes θ,
The resonator was rotated in the φ direction and the resonator was adjusted to satisfy the oscillation conditions.

[0006]

SUMMARY OF THE INVENTION A semiconductor laser-excited solid-state laser is small and can stably obtain high-output near-infrared light or visible light both in terms of time and frequency. However, adjustment of the optical axis in assembling the laser device is troublesome, and particularly adjustment of the resonator as the oscillator is the most difficult.
In the case of adjustment in the θ and φ directions such as the mirror holder, if the size is reduced, the accuracy of the adjustment becomes coarse, and it becomes more difficult to adjust the resonator.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser device which can easily and accurately satisfy a resonator condition.

[0008]

According to the present invention, there is provided a laser apparatus comprising: (1) at least a semiconductor laser for excitation, a laser oscillation material and a spherical output mirror, and light from the semiconductor laser to the laser oscillation material. And a coupling optical system for forming a resonator on the fixed base , the resonator comprising an excitation-side end face of the laser oscillation material and the output mirror.
Up and down with respect to the optical axis of the semiconductor laser
And the laser oscillation material by linearly moving left and right.
Changing the position at which the material is excited by the semiconductor laser,
This is for adjusting the oscillation conditions of the resonator .

[0009]

[0010]

According to the present invention, in a semiconductor laser pumped solid-state laser, an output mirror having a resonator structure is provided with an adjusting mechanism for linearly moving up and down and left and right, so that the resonator conditions can be easily and accurately satisfied. became.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the schematic configuration diagram of FIG. 5, a semiconductor laser pumped solid-state laser converts light emitted from a semiconductor laser 501 into a parallel beam by a collimating lens 502, and a laser material (for example, Nd) by a focusing lens 503. : YVO ₄ ) 504. Nd: YVO ₄
The end face 505 of the semiconductor laser 504 has a wavelength (809 nm) of a semiconductor laser.
An anti-reflection (AR) coat, a high reflection (HR) coat for an oscillation wavelength (1.064 μm) and a harmonic wavelength (532 nm) are applied. The end face 506 is provided with an AR coating for 1.064 μm and 532 nm. The output mirror 507 is coated with a coating having a reflectivity of 97% for a wavelength of 1.064 μm, and a fundamental wave of 1.064 μm is formed between the output mirror 507 and the end face 505 of Nd: YVO ₄ 504.
m resonators are constructed.

In general, a flat mirror or a spherical mirror is used as the output mirror 507, but a spherical mirror is used for high efficiency oscillation. For example, since the shape of a spherical mirror having a polar ratio of 50 mm is a part of a sphere having a radius of 50 mm, the same state of oscillation can be obtained using any part of the spherical mirror.

FIG. 1 shows a schematic configuration diagram of an adjusting mechanism of a resonator structure according to the present invention. The resonator is composed of the incident side end face of Nd: YVO ₄ 104 and the output mirror 102, and the length of the resonator is 50 mm. The Nd: YVO ₄ 104 and the output mirror 102 have the same coating as the schematic configuration diagram of FIG. The output mirror holder 101 of FIG. 1 is different from the output mirror holder 601 shown in FIG. 6 in that, for example, a screw or a micrometer 103 is attached to the upper or lower part and the side of the output mirror holder so that the output mirror 102 moves up, down, left, and right. Installed. The output mirror 102 is fixed to the holder with an adhesive or a screw. The output mirror 102 is a spherical mirror having a porosity of 50 mm. By moving the output mirror 102 up, down, left, and right, a part of the spherical surface can satisfy the oscillation condition of the resonator.

The accuracy of the conventional output mirror holder and the mirror holder of the present invention will be described with reference to FIGS. 1 and 6, the size of the output mirror holders 101 and 601 is about 10 mm square, the resonator length is 50 mm, and the porosity of the output mirror is 50 mm. Here micrometer 103
2 and 3, how much the optical axis of the output mirror deviates from the resonance condition when 10 and 603 are moved by 10 μm.

In the conventional output mirror of FIG. 2, a micrometer is attached at a point 5 mm away from the center of the output mirror. This micrometer has an output mirror 60
2 is to be moved in the θ and φ directions. When this micrometer is moved by 10 μm, the output mirror becomes A
To B. The tilt angle θ ₁ of the output mirror accompanying this movement is θ ₁ = 10 μm / 5 mm = 2 (mrad).

On the other hand, in the output mirror of the present invention shown in FIG.
When moved, the tilt angle θ ₂ of the output mirror 102 accompanying this movement is θ ₂ = 10 μm / 50 mm = 0.2 (mrad).

From the above, the inclination angle of the output mirror of the mirror holder of the present invention is one-tenth of that of the conventional mirror holder for the same moving amount of the micrometer, and the output mirror can be adjusted with higher precision. I understand.

FIG. 4 is a schematic structural view of an adjusting mechanism of the resonator structure according to the present invention. FIG. 4 differs from FIG. 1 in that the resonator is adjusted not by moving only the output mirror but by moving the entire resonator composed of the laser material and the spherical output mirror. is there.

The Nd: YVO ₄ 401 and the output mirror 402 are mounted on a YZ fixed base 403 made of brass, invar, or stainless steel and movable in the YZ directions. N
d: YVO ₄ 401 and output mirror 402 are coated with the same coating as in FIG. 5, and a resonator is formed between end face 404 and output mirror 402. Since Nd: YVO ₄ 401 is excited by a semiconductor laser and rises in temperature to 100 ° C. or higher, it is fixed with an adhesive having good thermal conductivity. Nd: YVO ₄ 401
Has a size of 5 mm square and a thickness of 0.5 mm. The semiconductor laser for excitation is focused on the end face 404 of Nd: YVO ₄ 401 to a diameter of about 10 μm. End face 4 of Nd: YVO ₄ 401
04 (not shown) is coated on the entire surface with a high reflectance coating for a wavelength of 1.064 μm.
It is possible to oscillate even if any part of is used as a resonator.
A spherical mirror with a radius of curvature of 50 mm is used as the output mirror
Was done. From this, YZ from the optical axis of the semiconductor laser
When the fixed base 403 is moved up, down, left and right, the output mirror can be adjusted with high accuracy by the same principle as that of FIG. That is,
As shown in FIG. 5, which is a conventional example, a semiconductor laser 5 for excitation
01, collimating lens 502, focusing lens
The member corresponding to 503 is on the back of Nd: YVO ₄ 401 in FIG.
It is placed on a fixed stand independent of the YZ fixed stand,
YZ fixed table 40 with respect to the optical axis of the semiconductor laser for excitation
3 moves in the YZ directions, so that the end face 4 of Nd: YVO ₄ 401
The condensing point on 04 also moves in the YZ directions. This allows
It is the same as moving the output mirror up, down, left and right in FIG.
The effect is obtained, and the resonator condition can be adjusted. As schematic diagram of FIG. 4, when installed the output mirror and the laser material to the same fixed base, the laser material and the output Mi against vibration
Since the tuning is performed , a more stable resonator can be obtained.

In this embodiment, Nd-doped YVO ₄ is used for the laser crystal. However, rare-earth-doped YAG, LiSrF, LiCaF, YLF, NAB, KNP, LNP, NYAB, NPP, and GGG are used for the solid laser material. By using a suitable material, near-infrared light of another wavelength can be obtained.

In the present invention, near-infrared light can be resonated. However, an organic nonlinear optical material or another inorganic nonlinear optical material such as KTP (KTiOPO ₄ ), KN (KNbO ₃ ), KAP (KAsOPO ₄ ), BBO, LBO
Also, by inserting a bulk type domain inversion element (LiNbO ₃ , LiTaO ₃ etc.), visible light (red, green, blue
etc.).

[0022]

In the solid-state laser pumped by a semiconductor laser, by providing an adjusting mechanism for linearly moving up and down and left and right on an output mirror having a resonator structure, highly accurate adjustment of the resonator can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an adjustment mechanism of a resonator structure according to the present invention.

FIG. 2 is an explanatory view of an adjusting mechanism of a resonator structure according to the present invention.

FIG. 3 is an explanatory view of a conventional adjusting mechanism of a resonator structure.

FIG. 4 is a schematic configuration diagram of an adjustment mechanism of a resonator structure according to the present invention.

FIG. 5 is a schematic configuration diagram of a semiconductor laser pumped solid laser.

FIG. 6 is a schematic configuration diagram of a conventional adjusting mechanism of a resonator structure.

[Explanation of symbols]

101 output mirror holder 102 output mirror 103 micrometer 104 Nd: YVO ₄ 401 Nd: YVO ₄ 402 output mirror 403 YZ fixed table 501 semiconductor laser 502 collimating lens 503 focusing lens 504 Nd: YVO ₄ 505 end face 506 end face 507 output mirror 601 output Mirror holder 602 Output mirror 603 Micrometer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-48-66986 (JP, A) JP-A-4-101479 (JP, A) JP-A-3-3378 (JP, A) 156775 (JP, U) Hikaru Hei 3-81664 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01S 3/05-3/0947

Claims (1)

(57) [Claims] At least a semiconductor laser for excitation,
A laser oscillation material and an output mirror having a spherical shape, and a coupling optical system for guiding light from the semiconductor laser to the laser oscillation material, wherein a resonator is provided from the excitation side end face of the laser oscillation material and the output mirror. By moving the resonator formed on the fixed base linearly up and down and left and right with respect to the optical axis of the semiconductor laser, the position where the laser oscillation material is excited by the semiconductor laser is changed . A laser device for adjusting oscillation conditions of the laser.