WO2008006505A2

WO2008006505A2 - Laser device

Info

Publication number: WO2008006505A2
Application number: PCT/EP2007/005967
Authority: WO
Inventors: Maxim Darsht; Aleksei Mikhailov; Vitalij Lissotschenko; Iouri Mikliaev
Original assignee: Limo Patentverwaltung Gmbh & Co. Kg.
Priority date: 2006-07-14
Filing date: 2007-07-05
Publication date: 2008-01-17
Also published as: WO2008006505A3

Abstract

The invention relates to a laser device comprising at least one semiconductor laser (1, 1') and/or at least one optical semiconductor amplifier that is provided with a plurality of emitters (6). The inventive laser device further comprises means for coupling the phase of the laser light (11) of at least a plurality of the emitters, particularly all the emitters (6), said phase coupling means being arranged outside the semiconductor laser (1, 1').

Description

"Laser device"

The present invention relates to a laser device comprising at least one semiconductor laser and / or at least one semiconductor optical amplifier having a plurality of emitters.

Such semiconductor lasers, which are embodied, for example, as laser diode bars, represent a significant advancement in terms of beam quality over conventional wide-band laser diode bars, which can only emit multi-mode laser radiation. In the case of these single-mode laser diode bars, which are comparatively new on the market, a plurality, for example 49, single-mode individual lasers are arranged at a distance from one another in a bar. Each of these single lasers has a beam quality factor M ² of 1 or slightly more than 1. The diffraction factor M ² is a measure of the

Quality of the laser beam. Due to the fact that in a single-mode laser diode bar, for example, 49 single-mode single lasers are combined, the entire laser light emanating from the single-mode laser diode bar has a diffraction factor M ² of 49 or not much more than 49. These

Diffraction factor M ² is approximately equal to 49 and thus much smaller than in conventional multi-mode laser diode bars. Their diffraction factor M ² can be significantly more than 1000. But this is the light of the single-mode laser diode bar much better coupled into an optical fiber with a small cross-section.

A disadvantage of conventional laser devices with such single-mode laser diode bars proves to be the fact that even the diffraction factor M ² of about 49 or more is still relatively large, so that the focusability of such Laser radiation into an optical fiber with a small cross-section is still not very good. The same applies to the focusing in a small focus area for welding or cutting applications, for example, where a power density of 10 ⁶ W / cm ^{2 is} required. Such power densities can be achieved with single-mode

Laser diode bars are achieved under optimal conditions. However, then no power reserve remains.

The problem underlying the present invention is thus the creation of a laser device of the type mentioned, which is better focusable.

This is inventively achieved by a laser device of the type mentioned above with the characterizing features of claim 1. The subclaims relate to preferred embodiments of the invention.

According to claim 1 it is provided that the laser device comprises means for r phase coupling of the laser light of at least a plurality of emitters, in particular of all emitters, wherein the means for phase coupling are arranged outside the at least one semiconductor laser. By a phase coupling of the laser light of a plurality of the emitter, in particular by a phase coupling of the

Laser light of all the emitters can be achieved so that the semiconductor laser no longer lasing on a number of modes corresponding to the number of emitters, but that ideally the semiconductor laser only lasers in a single longitudinal and / or transversal mode. This would ideally result in a single

Mode laser light with a diffraction factor of M ² = 1 or insignificantly larger = 1. However, this laser light can be focused much better in an optical fiber of small cross-section than the light of a known from the prior art Laser device. In particular, this results in a significantly greater light power which can be coupled into an optical fiber.

There is the possibility that the means for phase coupling comprise lens means for Fourier transformation of the laser light. For example, it may be provided that the means for

Phase coupling comprise mirror means, of which the laser light can be partially reflected back into the at least one semiconductor laser.

It can be provided according to a preferred embodiment of the present invention that the mirror means in the

Fourier level of the lens means are arranged. In particular, in such an arrangement, the mirror means may comprise spaced first portions which may at least partially reflect the laser light, between these first portions second portions are angeord net, which have a different, in particular a lower reflectivity for the laser light than the first sections, wherein the second portions, in particular, can not reflect the laser light or only to a small degree or only scattering back into the at least one semiconductor laser. In this case, the first and the second sections may be arranged such that they correspond to a Fourier-transformed intensity distribution of the phase-coupled laser light of a plurality, in particular all emitters of the semiconductor laser in the Fourier plane of the lens means. In this way it can be ensured that only those portions of the laser light which correspond to the complete phase coupling of the laser light of a plurality, in particular of all emitters, are effectively reflected back into the semiconductor laser and influence the mode spectrum of the semiconductor laser. Ideally, therefore, due to this measure, the semiconductor laser becomes on a single longitudinal and / or transversal mode to lasers, so that ultimately single-mode laser light can be generated.

According to a preferred embodiment of the present invention, it is possible for the laser device to comprise a lens array on which the mirror means are formed, for example by means of a corresponding surface coating. This lens array can simultaneously serve for collimating the laser light. For this reason, it can be provided that the reflective surface coating is formed as only partially reflective coating, so that a part of the

Laser light is coupled out through the lens array, whereas another part for influencing the mode spectrum is reflected back into the semiconductor laser. It proves to be advantageous in this case that, depending on the design of the lens means, the distances of the first sections from each other in the Fourier plane or in the plane of the lens array can be greater than the distances between the individual emitters of the semiconductor laser. For this reason, the use of a lens array with a comparatively large distance between the individual lenses relative to one another is possible in the Fourier plane, so that the manufacturing costs of this lens array can thereby be reduced compared to lens arrays which would be arranged, for example, directly behind the single-mode laser diode bar.

There is the possibility that the means for phase coupling comprise a spatial filter. This can be arranged in the Fourier plane of the lens means. Due to this arrangement, also after feedback of a part of the laser light into the semiconductor laser, the phase and possibly also the wavelength of the laser light emitted by the emitters can be influenced. There is also an alternative or additional possibility that the means for phase coupling comprise at least one seed laser whose laser light can be at least partially coupled into the semiconductor laser. It can be provided that the at least one seed laser as a single-mode

Laser diode or as a laser diode bar with single-mode single emitters or as an array of single-mode laser diodes is formed. In this way it can be ensured that the at least one semiconductor laser lasers in a single longitudinal and / or transverse mode. It may be provided that the seed laser is used only for adjusting the laser device.

It may further be provided that the emitters of the at least one semiconductor laser are designed such that they can each generate single-mode laser light.

There is the possibility that the semiconductor laser is designed as a laser diode bar with single-mode single emitters or as a stack of laser diode bars with single-mode single emitters. Furthermore, there is the possibility that the laser device comprises a plurality of laser diode bars with single-mode single emitters or also a plurality of stacks. In this case, an antireflection coating may be provided on one or both end surfaces of the semiconductor laser, so that it no longer serves as a laser but as an optical amplifier. Further features and advantages of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings. Show in it

Fig. 1 is a schematic side view of a first

Embodiment of a device according to the invention;

FIG. 2 shows a first embodiment of a lens array serving as a mirror means; FIG.

3 shows a second embodiment of a lens array serving as a mirror means;

4 shows a schematic illustration of the phase coupling in a laser device according to the invention;

Fig. 5 is a schematic side view of another

Embodiment of a laser device according to the invention;

Fig. 6 is a schematic plan view of the embodiment of FIG. 5;

Fig. 7 is a schematic side view of another

Embodiment of a laser device according to the invention;

8 shows a schematic side view of a further embodiment of a laser device according to the invention; 9 shows a clarification of the separation of an incident portion of the laser light from a reflected-back portion of the laser light by means of polarization cubes;

Fig. 10 is a schematic side view of another embodiment of an inventive

Laser device;

FIG. 1 shows a laser device according to the invention comprising a semiconductor laser 1, a lens means 2 and a lens array 3. The semiconductor laser 1 may be formed, for example, as a laser diode bar with single-mode single emitters.

The lens means 2 may be a plano-convex or biconvex lens or a multiple lens. The lens array 3 may for example be a cylindrical lens array, wherein in the illustrated embodiment, the cylinder axes may extend into the plane of the drawing.

It can be provided in particular that the distance between the lens means 2 to the semiconductor laser 1 and to the lens array 3 is in each case the same size, in particular as large as the focal length of the lens means 2. In this case, a Fourier transformation results in the intensity distribution of the laser light in the

Exit plane 4 of the semiconductor laser in the entrance plane 5 of the lens array. 3

In Fig. 1, the individual emitter 6 of the semiconductor laser 1 are illustrated by dots. The laser light emanating from them is superimposed by the lens means 2 in the entry plane 5 in such a way that there arises a Fourier transformation of the intensity distribution in the exit plane 4. 2, an exemplary embodiment of the lens array 3 is indicated. The lens array 3 comprises on its entrance side a plurality of parallel aligned cylindrical lenses 7, on whose crests first sections 8 are arranged, which are partially mirrored. For example, the first portions 8 may have a reflectivity between 10% and 20%. The second sections 9 arranged between these first sections 8 consist in part of the flanks of the cylindrical lenses 7 and partly of the wave troughs 10 of the cylindrical lenses 7. These wave troughs 10 can in particular be roughened or coated in a targeted manner, so that no reverse reflection can take place from these areas. From the flanks of the cylindrical lenses 7, no direct or only a very small back reflection of the laser light can take place. Only the first sections 8 are provided with a partially reflective coating, so that the laser light 1 1 occurring on these first sections 8 is reflected back as a reflecting laser light 12. The non-reflected portions of the laser light 1 1 pass through the lens array 3 and can be collimated by this, for example, in a manner known per se from the prior art.

In particular, it can be provided that the arrangement of the first sections 8 in the entrance plane 5 or in the Fourier plane of the lens means 2 corresponds to a Fourier transformation of an intensity distribution of the laser light, which would result if all emitters 6 were phase-locked. With others

Words can by the in Fig. 2 or in Fig. 3 example indicated arrangement of the first sections 8 can be achieved that only laser light 12 is reflected back, which corresponds to a phase-locked operation of all the emitter 6 of the semiconductor laser 1. The width of the first portions 8 in the direction in which the first and the second portions 8, 9 arranged side by side are, is small compared to the center distance (pitch) P ₂ of the first portions 8. For example, in a number of 50 emitters 6, which are operated out of phase coupled, the pitch P ₂ is about 50 times as large as the width of each of the first portions 8 For example, the pitch P _{2 may be} about 0.5 mm and the width of the first portion may be about 10 μm. This corresponds to a Fourier transformation of the phase-coupled intensity distribution of the emitters 6. In this Fourier transformation, narrow maxima are separated by large regions in which the intensity is zero or approximately zero.

In Fig. 4, a phase-coupled state of the back-reflected laser light 12 is indicated. In this case, levels 13 of the same phase of the laser light 12 are indicated. The laser light 12 is reflected back from the first portions 8 by the lens means 2 in the emitter 6 and affects after entering the emitter 6 the

Phase and possibly also the wavelength of the emitted from these emitters 6 laser light. Due to the feedback of the laser light 12 according to the invention, it would be possible, in the ideal case, to achieve that all the emitters are phase-coupled, and thus the entire semiconductor laser only lasers in a longitudinal and / or transversal mode. A phase-coupled state indicated in FIG. 4 can be found both in the embodiments according to FIGS. 1 to 3 and in the embodiments of FIGS. 5 and 6, FIG. 7, described in detail below. 8 and Fig. 10 are present.

Fig. 3 shows a Fig. 2 corresponding embodiment in which the first portions 14 are formed in the troughs of the cylindrical lenses 7. In this embodiment, the wave crests 15 are coated or roughened, so that they can not be targeted back reflection. Between the first one Sections 14 in FIG. 3, second sections 16 extend, which in addition to the flanks of the cylindrical lenses 7 also include the correspondingly treated wave crests 15.

In particular, the spacing between the individual sections 8, 14 relative to one another in the direction in which the sections 8, 14 are arranged next to one another can be significantly greater than the spacing of the individual emitters 6 relative to one another. In particular, the pitch P _{2 of} the first sections 8, 14 (see FIG. 2) relates to the center distance Pi of the emitter 6 (see FIG. 4) as well

with λ equal to the wavelength of the laser light. F denotes the focal length of the lens means 2. Thus, for a given wavelength of the laser light by suitable choice of the focal length of the lens means 2, the center distance P _{2 of} the first sections are selected to each other. In particular, the center distance can be chosen to be significantly larger than the center distance Pi of the emitter to each other. In this way, however, a lens array 3 can also be manufactured with respect to devices known from the prior art with considerably less effort, so that the laser light can collimate. On the other hand, even with technically possible single-mode

Laser diode bar with significantly smaller center distance Pi, as is common nowadays, by a suitable choice of the focal length of the lens means 2, a lens array 3 are used for collimating the laser light. In particular, it is no longer necessary, as known from the prior art, to position a lens directly in front of each emitter 6.

Due to the phase coupling achieved with the device according to the invention can stabilize the wavelength of the Laser light can be achieved. Furthermore, the laser light emitted by the semiconductor laser 1 can have a smaller spectral width than the laser devices known from the prior art. Furthermore, the phase coupling makes the laser device more stable, in particular more independent of external influences such as temperature changes, vibrations and the like.

In the embodiment according to FIG. 5 and FIG. 6, the same parts are provided with the same reference numerals as in FIG. 1. Instead of a partially mirrored lens array, a spatial filter 17 is used which is arranged in a Fourier plane 18. Furthermore, a partially transmissive mirror 51 is provided.

The laser light 52 emanating from the semiconductor laser 1 is collimated by collimating lens means disposed behind the semiconductor laser 1. This can be a fast-axis collimation lens

53 and a slow axis collimating lens array 54. In the propagation direction of the laser radiation behind these collimating lens means, lens means 55 are provided, which in the illustrated embodiment consist of three separate lenses 56, 57, 58. The lenses 56, 58 are cylindrical lenses whose cylinder axes extend in the Y direction, so that they only influence the slow axis of the laser light 52. In contrast, the middle lens 57 is a cylindrical lens whose cylinder axis extends in the X direction so as to influence only the fast axis of the laser light 52.

The focal lengths of the lens means 55 are chosen so that a

Fourier transformation from a plane 59 into which the Fourier plane 18 takes place. The plane 59 may have a distance from the exit plane 4, which corresponds to twice the focal length f of the fast-axis collimating lens 53. In particular, the Distance of the central lens 57 from both the plane 59 and the Fourier 18 correspond to twice their focal length F.

In the simplest case, the spatial filter 17 arranged in the Fourier plane 18 may consist of a disk with a hole or a gap. But there is also the possibility of a hole or

Provide gap pattern that corresponds to a Fourier transform an intensity distribution of the laser light, which would result if all emitters 6 were phase-coupled.

Between the spatial filter 17 and the partially transmitting mirror 51, there is provided a lens means 60 which is shown in FIG

Embodiment is designed as a biconvex lens. The distances between the spatial filter 17 and 51 the lens means 60 and between the lens means 60 and the partially transmissive mirror 51 respectively correspond to the focal length F of the lens means 60. The intensity distribution in the Fourier plane 18 is thus Fourier-transformed into the plane of the partially transmissive mirror 51, so that an inverse transformation takes place.

Behind the partially transmissive mirror 51, lens means 61 are provided which can couple the laser light passing through the mirror 51 into an optical fiber 62. The laser light reflected back from the partially reflecting mirror is coupled into the individual emitters 6 and, after entering the emitters 6, influences the phase and possibly also the wavelength of the laser light emitted by these emitters 6. Thus, in the ideal case, a phase-locked operation can be realized, as in

Fig. 4 is shown.

It is possible, one or more correction elements for optical path extension and thus for phase matching in the To arrange device. These may be, for example, glass blocks or glass wedges. Such correction elements for the optical extension of partial beams of the laser light 52 may be required if the individual emitters 6 are offset from one another, for example due to a so-called "smiley face".

Glass wedges have the advantage that they can be displaced, thereby changing the path difference caused by them. "Preferred locations for the arrangement of the optical extension elements are the plane 59 and the Fourier plane 18.

The embodiments of laser devices according to the invention depicted in FIGS. 7, 8 and 10 each include a seed laser 19; this seed laser 19 may in particular be a single-mode laser diode. Also by the use of such a seed laser 19, a phase-locked operation can be realized, as shown in Fig. 4.

In the embodiment according to FIG. 7, the laser light 20 of the seed laser 19 is coupled via a collimating lens 21 and a lens array 22 into the side opposite the exit side of the emitter 6 of the semiconductor laser 1 (from the left in FIG. 7). The light emerging from this to the right in FIG. 7 may be phase-locked and is collimated, for example, by a lens array 23.

In the embodiment of FIG. 8, the coupling of the laser light 20 of the seed laser 19 via the exit plane 4 of the emitter 6 and thus from the right in Fig. 8. This is done before the

Lens array 23 arranged at the same time for coupling in the laser light of the seed laser 19. The generally linearly polarized laser light 20 is deflected via a polarization cube 24 to a Faraday rotator 25, which in particular the Polarization direction of the laser light can rotate by 45 °. Since the Faraday rotator 25 irrespective of the direction of propagation of the light passing through it, the polarization direction each time in the same direction d re, the polarization direction by another 45 ° gedet by the repeated passage, so that the exiting from the emitters laser light 26th to the right in Fig. 8 passes through the polarizing cube 24 hind. Instead of the Faraday rotator 25, another non-reciprocal optical element may be used.

In Fig. 9, the rotation of the linear polarization direction of light

27 be clarified. For this purpose, a quarter wavelength plate 28 and a mirror 29 are shown in FIG. 9 next to the polarization cube 24. The light 27 entering the polarizing cube 24 from above in FIG. 9 is deflected to the left in FIG. 9 because of its linear polarization direction. There it passes through the quarter wavelength plate 28 and is converted to circularly polarized light 30. This light 30 is reflected on the mirror 29 and undergoes a phase jump. Due to the phase jump, the back-reflected light 31 is linearly polarized by the quarter wavelength plate 28

Converted light 32 with a polarization direction which is perpendicular to that of the original light 27. Thus, however, this light 32 will pass through the polarization cube 24 from left to right. This effect is the effect in Fig. 10 illustrated embodiment to use, ie he will be described in more detail below.

The laser light 20 emanating from the seed laser 19 is deflected onto a lens array 34 via a beam splitter optics 33. After passing through the lens array 34, the laser light 20 passes through an additional collimating lens 35 and is then from a polarization cube 36 to the left in Fig. 10 deflected. A left side adjoining quarter wavelength plate 37 converts the laser light 20 into circularly polarized laser light 38. This laser light 38 is split in a further polarization cube 39 into two linearly polarized laser light components 40, 41 with mutually perpendicular polarization direction. These laser light components 40, 41 are coupled via lenses 42, 43 and lens arrays 44, 45 into two semiconductor lasers 1, 1 'and influence their mode spectra. Before the lower semiconductor laser 1 in Fig. 10, a half-wavelength plate 46 is still arranged to the

Polarization direction to rotate by 90 ° (see the polarization directions clarifying arrows 47, 48 in Fig. 10). This polarization direction rotated by 90 ° corresponds to that of the semiconductor laser 1, so that a more efficient coupling or phase coupling is made possible.

The laser light components 40, 41 coupled into the semiconductor lasers 1, 1 'undergo reflection on the rear sides of the semiconductor lasers 1, 1' and thus a phase jump. As a result, after merging the laser light components 40, 41 in the polarization cube 39, that propagates to the right in FIG

Laser light 49 has a circular polarization which rotates the other way round than that of the oppositely moving laser light 38. However, after passing through the quarter wavelength plate 37, laser light 50 with a linear polarization perpendicular to that of the originally coupled laser light 20 of the

Seed laser 19 is aligned. Thus, however, the phase-coupled laser light 50 emanating from the semiconductor lasers 1, 1 'occurs to the right in FIG. 10 through the polarizing cube 36 therethrough.

In this way, an elegant coupling of the laser light 20 of the seed laser 19 into the semiconductor laser 1, 1 'is achieved. It exists definitely the possibility to couple in this way, the laser light 20 in only one or more than two semiconductor lasers 1, 1 '.

Furthermore, it is possible to couple the laser light 20 of the seed laser 19 into the at least one semiconductor laser 1 in various ways. On the one hand, a Fourier transformation of the

Laser light 20 are performed on the exit plane 4 of the semiconductor laser 1. On the other hand, an image of the laser light on the exit plane 4 of the semiconductor laser 1 can be performed. Furthermore, it is possible to let the laser light 20 of the seed laser 19 enter the at least one semiconductor laser 1 as a plane wave.

There is also the possibility of combining the active phase coupling by means of seed laser 19 with the passive phase coupling by Fourier transformation (see the embodiments according to FIGS. 1 to 6).

There is also the possibility of providing the end faces of the semiconductor laser 1 with an antireflection coating so that no appreciable reflections occur at these end faces. In this case, the semiconductor laser 1 does not function as a laser but as an optical amplifier for that of the seed laser

19 outgoing laser light. Alternatively or additionally, partially reflective coatings may also be provided on one or both end surfaces.

Claims

claims:

1 . Laser device comprising at least one semiconductor laser (1, 1 ') and / or at least one semiconductor optical amplifier having a plurality of emitters (6), characterized in that the laser device

Means for phase coupling of the laser light (1 1, 26, 50, 52) at least a plurality of emitters (6), in particular all the emitter (6), wherein the means for phase coupling outside the at least one semiconductor laser (1, 1 ') arranged are.

2. Laser device according to claim 1, characterized in that the means for phase coupling lens means (2, 55, 60) for Fourier transformation of the laser light (1 1, 52).

3. Laser device according to one of claims 1 or 2, characterized in that the means for phase coupling

Mirror means comprise, of which the laser light (1 1, 52) partially in the at least one semiconductor laser (1, 1 ') can be reflected back.

4. Laser device according to claim 3, characterized in that the mirror means in the Fourier plane of the lens means (2,

60) are arranged.

5. Laser device according to one of claims 3 or 4, characterized in that the mirror means spaced-apart first portions (8, 14) which at least partially the laser light (1 1) can reflect, wherein between these first portions (8, 14) second portions (9, 16) are arranged, which have a different reflectivity for the laser light (1 1) than the first portions (8, 14).

6. Laser device according to claim 5, characterized in that the second sections (9, 16) have a lower reflectivity for the laser light (1 1) than the first sections (8, 14).

7. Laser device according to claim 6, characterized in that the second portions (9, 16) the laser light (1 1) can not reflect or only in a small extent or only scattering in the at least one semiconductor laser (1, 1 ') back.

8. Laser device according to one of claims 5 to 7, characterized in that one of the second sections (9, 16), in particular each of the second sections (9, 16), in the direction in which the first sections (8, 14) are juxtaposed, is wider than one of the first portions (8, 14), in particular as each of the first portions (8, 14).

9. Laser device according to claim 8, characterized in that one of the second sections (9, 16), in particular each of the second sections (9, 16), in the direction in which the first sections (8, 14) are arranged side by side, at least twice as wide, preferably at least ten times as wide, for example between 40 and 60 times as wide as one of the first sections (8, 14), in particular each of the first sections (8, 14).

10. Laser device according to one of claims 8 or 9, characterized in that one of the second sections (9, 16), in particular each of the second sections (9, 16), in the direction in which the first sections (8, 14) juxtaposed, by a factor wider than one of the first Sections (8, 14), in particular each of the first sections (8, 14), this factor corresponding approximately to the number of emitters (6).

1 1. A laser device according to one of claims 5 to 10, characterized in that the first and the second sections

(8, 9, 14, 16) are arranged such that they have a Fourier-transformed intensity distribution of the phase-coupled laser light (1 1) of a plurality, in particular of all emitters (6) of the semiconductor laser (1, 1 ') in the Fourier plane of the lens means (2). correspond.

12. Laser device according to one of claims 3 to 1 1, characterized in that the laser device comprises a lens array (3) on which the mirror means, for example by appropriate surface coating, are formed.

13. Laser device according to one of claims 1 to 12, characterized in that the means for phase coupling comprise a spatial filter (17).

14. Laser device according to claim 13, characterized in that the spatial filter (17) in the Fourierbene (18) of the lens means (55) is arranged.

15. Laser device according to one of claims 1 to 14, characterized in that the means for phase coupling comprise at least one seed laser (19) whose laser light (20) at least partially in the at least one semiconductor laser (1, 1 ') can be coupled ,

16. Laser device according to claim 15, characterized in that the at least one seed laser (19) as a single-mode Laser diode or as a laser diode bar with single-mode single emitters or as an array of single-mode laser diodes is formed.

17. Laser device according to one of claims 15 or 16, characterized in that the laser light (20) of the at least one seed laser (19) through the exit plane (4) or through an opposite surface in the at least one semiconductor laser (1, 1 ') can occur.

18. Laser device according to one of claims 1 to 17, characterized in that the emitter (6) of the at least one

Semiconductor laser (1, 1 ') are designed such that they each can generate single-mode laser light (1 1, 26, 50).

19. Laser device according to one of claims 1 to 18, characterized in that the at least one as a laser diode bar with single-mode single emitters or as

Stack of laser diode bars with single-mode single emitters is formed.

20. Laser device according to one of claims 1 to 19, characterized in that the laser device comprises at least one correction element for optical path extension, which can adapt the phases of the different emitters (6) emanating laser light to each other.