JPH02260678A - Laser device - Google Patents

Abstract

PURPOSE:To obtain laser rays of a high output power with a simple structure by a method wherein a light ray route diverting means, which forms an optical path different from an oscillation optical path inside a laser medium and enables laser rays to travel through the above optical path diverting its route, is provided. CONSTITUTION:Resonating light (r) travels between a total reflection mirror 2 and a partially transmissive mirror 3 in a laser medium 1 irradiated with an exciting lamp 4 to start a laser oscillation so as to obtain laser ray r0. The laser ray r0 is diverted from its course as being reflected by reflective mirrors 5 and 6, incident on the laser medium 1, and optically amplified to be an intense laser ray r1 passing through the medium 1. The laser ray r1 is reflected by reflective mirrors 7 and 8 to be incident on the medium 1 passing through an optical path different from that of the laser ray r0. The laser ray r1 is amplified passing through the medium 1 and projected outside as an intense laser ray r2. In this case, the resonating light (r) and the laser rays r0 and r1 are made to pass different optical paths inside the medium 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser device having a function of laser oscillation and a function of optically amplifying the oscillation light.

[Prior Art] Laser devices that optically amplify oscillated laser light and output it as a powerful laser light have been known.

Fig. 2 is a block diagram showing an example of a conventional laser device of this type. Fig. 2(a) shows a case where the optical amplification stage is one stage, and Fig. 2(b) shows a case where the optical amplification stage is two stages. Each case is shown.

In the apparatus shown in FIG. 2(a), a high-quality laser beam r is oscillated by a laser oscillation stage consisting of a laser medium 201 made of glass or crystal, a total reflection mirror 202, a reflection mirror 203, and an excitation lamp 204. is passed through a laser medium 201a made of glass or crystal excited by an excitation lamp 204a, amplified at a predetermined amplification factor, and extracted as a large output laser beam r1. The excitation lamps 204 and 2.4a are driven by excitation lamp driving power supplies 205 and 205a, respectively.

The laser device shown in FIG. 2(b) is similar to the laser device shown in FIG. 2(a).
) In addition, one more layer is added to the optical amplification stage of the laser device shown in
It is equipped with an optical amplification stage.

That is, the laser medium 201b, the excitation lamp 204
This device is equipped with an optical amplification stage consisting of an excitation lamp driving power source 205b and an excitation lamp driving power source 205b.
2.

Further, as another example, there is one described in Japanese Patent Application Laid-Open No. 82-189778.

In this example, a wide slab-type laser medium is used, laser oscillation is performed in a part of this laser medium, and the oscillated laser beam is made incident on another part of the laser medium. It is designed to perform optical amplification.

[Problems to be Solved by the Invention] By the way, in the conventional laser device shown in FIG.
Equipment approximately equal to or greater than the laser oscillation stage is required. That is, in order to configure the optical amplification stage, at least the same laser medium as the laser oscillation stage, an excitation lamp, a power source for driving the excitation lamp, etc. are required.

For this reason, multiple amplification stages are used to achieve the desired high output.
When attempting to construct a laser device that obtains high-quality laser light, there are problems in that the device becomes complicated and large, difficult to install and adjust, and the manufacturing cost becomes extremely high.

Furthermore, the method described in JP-A-62-189778 requires a special shaped laser medium that is significantly wider than a normal laser medium for laser oscillation, and in order to excite this laser medium, In this case, it is necessary to use a special excitation lamp depending on the width of the laser medium, or to use a plurality of lamps, resulting in the same inconvenience as the example shown in Fig. 2 above. It will happen.

The present invention was made against the above-mentioned background, and provides a high-quality, high-output laser beam with a relatively simple configuration.
The object of the present invention is to provide a laser device that can be formed compactly, is easy to install and adjust, and is inexpensive to manufacture.

"Means for Solving the Problems" The present invention solves the above problems by having the following configuration.

A laser device having a function of laser oscillation and an optical amplification function of amplifying the laser light obtained by the laser oscillation, the laser device changing the course of the laser light obtained by the laser oscillation, The structure is characterized by comprising a beam path changing means configured to form an optical path different from a laser oscillation optical path in the laser medium in the laser medium in which the laser oscillates, and to cause the beam to pass through the laser medium.

[Function] In the above structure, the laser beam oscillated by the laser medium passes through the laser medium so as to form an optical path different from the laser oscillation optical path in the laser medium due to the action of the beam path changing means. . therefore,
Since the laser light is subjected to an amplification effect during this passage, by extracting this light, it is possible to obtain a laser light that is an amplified version of the oscillation laser light. In this case, since laser oscillation and optical amplification are performed using one laser medium, there is no need to provide a separate laser medium, excitation lamp, etc. for optical amplification.

[Example] (First Example) FIG. 1 is a block diagram showing a laser device according to a first example of the present invention. This embodiment is an example in which a slab type laser medium is used as the laser medium. The first embodiment will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a slab type laser medium, and reference numeral 2 indicates a slab type laser medium.
and 3 are a fully reflecting mirror and a partially transmitting mirror for forming a laser resonant optical path, respectively; numeral 4 is an excitation lamp; numeral 5 is
．． 6: 7. s is a reflecting mirror constituting the beam path changing means. Although not shown, the excitation lamp 4 is configured to be driven by an excitation lamp drive power source.

The slab type laser medium 1 has a length of 240' mm,
A plate-shaped laser glass with a width of 70 mm and a thickness of 20 mm (for example, LHG-5 manufactured by HOYA Corporation can be used)
The end face in the longitudinal direction is cut at an angle of 60' (angle α in FIG. 1) with respect to the longitudinal direction. Note that this end face is not Brewster's angle, so
It is coated with an anti-reflection coating (AR coating).

As is well known, this slab type laser medium 1 has the total reflection mirror 2 and the partial transmission mirror 3 disposed in a predetermined arrangement relationship, and excitation light is irradiated from the front and back surfaces by the excitation lamp 4. By doing so, resonant light r is formed that travels in a zigzag pattern through the laser medium 1 while being totally reflected alternately on the front and back surfaces, and travels between the total reflection mirror 2 and the partially transmission mirror 3. Laser oscillation is performed to obtain laser light RO.

Further, the reflecting mirror 5.6 reflects the oscillated laser beam ro, changes its traveling direction, and makes it enter the laser medium 1 from the entrance/exit surface of the laser resonant beam r of the laser medium 1. In this case, the incident direction is a direction in which the light beam travels in a zigzag manner through the laser medium 1, forming an optical path different from that of the laser resonance light r, and is emitted from the other end face.

Furthermore, the reflecting mirrors 7 and 8 receive the laser beam r that is incident on the laser medium 1 by the reflecting mirror 5.6. The course of the emitted light r1 from the other end face of the laser medium 1 is changed and the light r1 is made to enter the laser medium 1 again. In this case, the incident direction is such that the laser beam r1 passes through the laser medium 1 as a resonant beam r.
The light beam r2 travels along a different optical path from the optical path of the oscillation laser beam r□, and is emitted from the other end face in the form of a beam r2.

In the above configuration, the laser beam r obtained by laser oscillation by the laser medium 1, the total reflection mirror 2, and the partial transmission mirror 3. is optically amplified by passing through the laser medium 1, and becomes a laser beam r1 more powerful than ro. Furthermore, this laser beam r1 passes through the laser medium 1 again, is optically amplified, and becomes a more powerful laser beam r2. In this case, the resonance light r and the laser lights ro and rl each pass through separate optical paths in the laser medium 1.

According to this embodiment, one laser medium for normal laser oscillation and one laser medium for normal laser oscillation to excite the medium are used.
A laser device that performs laser oscillation and optical amplification can be constructed only by a set of laser medium excitation means (consisting of an excitation lamp, a power source for driving the lamp, etc.). In other words, this makes it possible to create a laser device that has a relatively simple configuration, is small, easy to install and adjust, is inexpensive to manufacture, and can obtain high-output laser light at a good price. This is what you are getting.

(Second Embodiment) FIG. 3 is a diagram showing the configuration of a laser device according to a second embodiment of the present invention. This embodiment is also an example in which a slab type laser medium is used as the laser medium.

In FIG. 3, numeral 21 is a slab type laser medium, numerals 22 and 23 are a total reflection mirror and a partial transmission mirror, respectively, for forming a laser resonant optical path, numeral P1 is a prism, and numeral Pc is a Q during laser oscillation. A Bockel cell for switching, symbol P O1 is a polarizer that converts the resonant light r into a linearly polarized light parallel to the plane of the paper in order to enable the Bockel cell Pc optical resonator loss modulation, and a symbol A1 is a polarizer that converts the resonant light r into a linearly polarized light parallel to the plane of the paper. This is an aperture that focuses the beam to convert the oscillation laser light ro into a laser light having a transverse mode of TEM00.

Also, the code P2. P3 is a prism, symbol L1°L2. P
4. P5 and P6 are used to transmit the circular oscillation laser beam r□ with a cross-sectional shape of 2 mm in diameter to the excitation cross-sectional shape of the laser medium 21 (
A spherical lens and a prism constitute a beam shaping means A2 that shapes the light into an elliptical diameter ro1 with a minor axis of 32 mm and a major axis of 60 mm, which has a shape approximating a width of 50 mm and a thickness of 20 mm. Note that the lenses L1 and L2 have a cross-sectional shape of 2. mm diameter circular laser beam r. The cross-sectional shape is 32
Change it to a circular light with a diameter of mm. Further, as shown in FIG. 4, the prisms P5 and P6 are arranged so that the incident angle θB of the light incident on each prism becomes the Brewster's angle. The beam shaping means A2 is configured to control the oscillation laser beam r.
The beam shape of the laser beam 21 is shaped to be substantially the same as the incident end face of the laser medium 21, so that optical amplification can be carried out effectively.

Further, reference numeral P7 denotes a columnar prism, and as shown in FIG. 5, the long axis (short axis) of the elliptical light emitted from the prism P6 can be rotated by 90' to be incident on the end face of the laser medium 21. At the same time, P-polarized light is converted to S-polarized light.

Further, reference numeral P o 2 is a polarizing plate that reflects S waves and transmits P waves, and the laser beam emitted from the columnar prism P 7 is polarized by r. 1 (S wave) is reflected and made incident on the laser medium 21. This laser beam r. 1 undergoes first optical amplification within the laser medium 21 and is emitted from the other end face of the laser medium 21 as an optically amplified laser beam r1.

Code M1. M2 is a reflecting mirror that reflects the laser beam r1 emitted from the laser medium 21 and makes it enter the laser medium 21 again. Also, code L3. L4 is a spherical lens constituting a so-called image relay 11 for preventing the transverse mode of the laser beam r1 from being distorted due to the long optical path from the laser medium 21 until it enters again. . Note 1. The focal point (fl, f
2) are the midpoint of the laser medium 21 and the reflecting mirror M1. It is located at the midpoint of the line connecting M2.

The laser light r11 that has passed through the image relay (1) enters the laser medium 21 again. The incident angle in this case is a different angle from that of the resonance light r and the emitted light r1. The laser beam r11 incident on the laser medium 21 undergoes a second optical amplification within the laser medium 21, and then the laser beam r11 enters the laser medium 21.
The amplified laser beam r2 is emitted from the other end face of the laser beam r2.

Symbol M3 is a relatively small reflecting mirror that reflects the laser beam r2 in the same direction as the incident direction, and symbols L5L6 and A3 are the small reflecting mirrors M that reduce the beam diameter of the laser beam r2.
The beam diameter r21 can be reflected by 3, and
It is a spherical lens and an aperture that return the light r21 reflected by the reflecting mirror M3 to the light r22 having the original beam diameter. Further, the symbol λ/4 is a 174-wave plate disposed between the spherical lens L6 and the reflecting mirror M3. This 17
By passing through the four-wavelength plate λ/4, the plane of polarization of the light is rotated by 45 degrees, so the light r that has passed through this twice
22 is the medium 2 which is converted from S wave to P wave as described above.
1 from the same direction as the emission direction of the laser beam r2. Laser light r2 incident on this laser medium 21
2 undergoes a third optical amplification within the laser medium 21 and becomes a laser beam r3, which is emitted from the other surface of the laser medium 21. Incidentally, the spherical lenses L5 and L6 constitute a second image relay (2).

The laser beam r3 follows an optical path opposite to that of the laser beam r11 (rl), becomes a laser beam r31, and enters the laser medium 21 again. The laser beam r31 incident on the laser medium 21 undergoes a fourth optical amplification within the laser medium 21, becomes a laser beam r4, and is emitted from the other end face of the laser medium 21. Since this laser beam r4 is a P wave, it is transmitted through the polarizing plate PO2.

Code P8. P9 is a prism constituting the beam cross section shaping means A4, which shapes the beam cross section of the laser beam r4 to form a rectangular beam r4 of 50 mm x 50 mm.
It is formatted into 1 and stored. Although not shown in FIG. 3, an excitation lamp is provided near the laser medium 21 so as to face the front and back surfaces of the laser medium 21, and this excitation lamp is driven. A power source for driving an excitation lamp is provided. Moreover, the prism p1. P2. P4, the columnar prism P7, the polarizing plate P02, and the reflecting mirrors Mi, M2, and M3 constitute a beam path changing means in the present invention.

FIG. 6 is an explanatory diagram of the optical path when each light beam passes through the laser medium 21 in FIG. 3. FIG. As shown in the figure, each ray r, ro2 . r11°r22. r31
is incident on the laser medium 21 where the center of the beam and the center of the incident end face of the laser medium 21 almost coincide.

Furthermore, FIG. 7 shows the incident angle θ (the angle that the incident ray makes with a straight line perpendicular to the end face) when light is incident on the laser medium 21, and the total reflection of this light within the laser medium 21. It is an explanatory diagram showing the relationship with the number of times.The laser medium 21 in this case has a length of 240 mm, a width of 70 mm,
A plate-shaped laser glass with a thickness of 20 mm (for example, HOY
LHG-5) manufactured by A Corporation.

In the above embodiment, the obtained laser beam r41(Q
The giant pulse laser beam produced by the switch is extremely powerful because it is obtained by optically amplifying the oscillation laser beam r□ four times. Moreover, the obtained laser beam r41 is TE
It is of extremely high quality and has a transverse mode of M00. That is, according to this embodiment, laser oscillation is performed using one laser medium 21, which is a normal slab type laser medium, and the oscillated laser light is optically amplified four times to produce extremely powerful and high-quality laser light with a good mode. This is what makes it possible to obtain.

Moreover, the cross-sectional shape of each light beam incident on the laser medium 21 for optical amplification is shaped so that the beam cross-section is approximately the same as the cross-section of the laser medium 21. Therefore, the optical amplification effect is performed throughout the laser medium 21, making it possible to perform extremely efficient optical amplification.

(Third Embodiment) FIG. 8 is a diagram showing the configuration of a third embodiment of the present invention, and FIG. 3 (a> is a plan view, and FIG. 3 (b) is a side view.
In this embodiment, a polygonal plate-shaped laser medium 31 is used as the laser medium.

In FIG. 3, a laser medium 31 and a
Laser oscillation is performed by a total reflection mirror 32, a partial transmission mirror 33, and an excitation lamp 34, which are arranged on both sides of the mirror. The oscillated laser beam r. The beam path is changed by the reflecting mirrors 35 and 36, and the beam is again incident on the laser medium 31 from a direction different from the direction of the resonant beam r in the laser oscillation.

The laser beam r''0 incident on the laser medium 31 is optically amplified by passing through the laser medium 31, becomes an amplified laser beam r1, and is emitted from the other end face of the laser medium 31.

This amplified laser beam r1 is further reflected by reflecting mirrors 37 and 38, changed course, and is made to enter the laser medium 31 again from a direction different from that of the resonance beam r and the amplified laser beam r1. . Then, the laser beam r1 undergoes a second optical amplification and becomes an even more powerful laser beam r2, which is emitted from the laser medium 31.

In this case, the reflecting mirrors 35, 36, 37, and 38 constitute the beam path changing means in the present invention.

Thereby, a powerful laser beam r2 can be obtained.

This embodiment also provides substantially the same effects as those of the embodiments described above.

[Effects of the Invention] As detailed above, the present invention provides a laser device having a function of laser oscillation and an optical amplification function of amplifying the laser light obtained by the laser oscillation. A beam path changing means for changing the path of the laser beam obtained by the laser beam so that the laser beam passes through the laser medium in which the laser oscillation is performed by forming an optical path different from the laser oscillation optical path in the laser medium. By adopting a configuration characterized by the following features, it is possible to obtain a high-quality, high-output laser beam, and it has a relatively simple configuration, can be formed into a small size1, is easy to install and adjust, and has a low manufacturing cost. This also provides an inexpensive laser device.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a laser device according to a first embodiment of the present invention, FIG. 2 is a block diagram showing an example of a conventional laser device, and FIG. 3 is a block diagram showing the configuration of a laser device according to a second embodiment. A block diagram showing the configuration, FIG. 4 is a partially enlarged view of FIG. 3, FIG. 5 is an explanatory diagram of the columnar prism P7 in FIG. 3, and FIG. 6 is a laser medium 21 passing through in FIG. 3. FIG. 7 is an explanatory diagram showing the relationship between the angle of incidence on the laser medium and the number of total reflections. FIG. 8 is a diagram showing the configuration of a third embodiment of the present invention. 1.21.31... Laser medium, 2.22.32...
・Total reflection mirror, 3, 23. 33...Partial transmission mirror, 4゜2
4.34...excitation lamp, 5, 35.6, 36°7
．． 37, 8.38. M engineering, M2, M3...Reflecting mirrors constituting the beam course changing means, Pi, P2, P4
...Prim, rhythm, P7 that constitutes the beam course changing means
...Columnar prism, PO2, which constitutes the light beam course changing means
...Polarizing plate that constitutes the beam path changing means.

Claims (1)

[Claims] A laser device having a function of laser oscillation and an optical amplification function of amplifying the laser light obtained by the laser oscillation, the laser device changing the course of the laser light obtained by the laser oscillation. A laser device comprising: a beam path changing means configured to form an optical path different from a laser oscillation optical path in the laser medium so that the laser beam passes through the laser medium in which the laser oscillates.