WO2008087008A1 - Apparatus for shaping a light beam - Google Patents

Abstract

Apparatus for shaping a light beam, comprising a first lens array (1) through which the light beam to be shaped can pass, a second lens array (2) which is arranged behind the first lens array (1) in the propagation direction of the light beam such that light which has passed through the first lens array(1) can pass through the second lens array (2), and first lens means (3) which are arranged between the first and the second lens array (1, 2) and can mutually superpose light components, which have passed through the first lens array (1), in the region of the second lens array (2).

Description

 "Apparatus for forming a light beam"

The present invention relates to a device for shaping a light beam according to the preamble of claim 1. Furthermore, the present invention relates to a laser device according to the preamble of claim 22. Furthermore, the present invention relates to

Invention a method according to the preamble of claim 25.

Definitions: In the propagation direction of the light to be influenced, the mean propagation direction of the light means, especially if this is not a plane wave or at least partially divergent. By light beam, sub-beam or beam is meant, unless expressly stated otherwise, an idealized beam of geometric optics, but a real light beam, such as a laser beam with a Gaussian profile, which has no infinitesimal small, but an extended beam cross-section. Pitch means the distance between the centers of the lenses

Arrays to each other in the direction in which the lenses are arranged side by side in the array.

From EP 1 489 438 A1 a device for shaping a light beam of the type mentioned is known. The device described therein comprises two arrays of cylindrical lenses, which are arranged one behind the other in the propagation direction of the light beam to be formed. Behind the second of the two lens arrays a biconvex lens is arranged, which can superimpose the light which has passed through the lens arrays in a working plane. By means of such a device, for example, a laser beam, which has a Gaussian profile corresponding intensity distribution, are formed such that it has a intensity distribution corresponding to a so-called top hat in the working plane. In such a device, individual points of an input-side intensity distribution are transmitted to specific points of an output-side intensity distribution. This proves to be disadvantageous, because thus the shape of the intensity profile in the working plane is highly dependent on the input side

Intensity distribution of the light beam to be formed. For example, a shift in the light beam on the input side or a change in the angle at which the light beam strikes the device causes a change in the shape of the intensity profile. Therefore, the adjustment of the device designed very expensive.

The problem underlying the present invention is the provision of a device for forming a light beam of the type mentioned, the more tolerant to input side changes in the intensity distribution of the forming

Light beam is, especially when the light of the light beam is coherent. Furthermore, a laser device of the type mentioned is to be developed. Furthermore, a method of the type mentioned is to be specified.

This is according to the invention in terms of the device for shaping a light beam by a device of the type mentioned above with the characterizing features of claim 1, with respect to the laser device by a laser device of the type mentioned above with the characterizing features of claim 22 and in terms of the method by a method of achieved at the outset type with the characterizing features of claim 25. The subclaims relate to preferred embodiments of the invention. According to claim 1 it is provided that the device comprises first lens means, which are arranged between the first and the second lens array and can pass through the first lens array passed through portions of the light before the second lens array or in the region of the second lens array with each other. The first lens array divides the input intensity distribution into several or many sections. The greater the number of lenses of the first lens array, the more defined is the intensity distribution of the portions of the light that have passed through the individual lenses. For example, the shape of the lenses may dictate an output intensity distribution, such as a top hat distribution. If the lenses of the first lens array are the same, each of the lenses will perform the same predetermined beam transformation. The intensity distributions of the individual sections or partial beams resulting from the passage through the lenses are superimposed by the first lens means in the region of the second lens array or shortly before it. Advantageously, the light of the light beam to be formed is coherent or at least partially coherent, so that this superposition leads to strong interference effects. The resulting interference patterns are periodic and repeat the input intensity distribution on a different scale several times. The envelope of this periodically repeating intensity distribution still has the desired given intensity distribution. In the area of this superimposition, the second lens array is positioned in order to straighten the interference patterns as much as possible and to keep only the envelope. The lenses of the second lens array may have a shape adapted to the input intensity distribution. The intensity distribution or field distribution resulting behind the second lens array is tolerant to changes in the intensity distribution before the first lens array. -A-

When changing this input-side intensity distribution only changes the overall intensity of the light beam, but not the intensity distribution or field distribution. By means of the device according to the invention, a defined output-side can be obtained from an input-side intensity distribution

Achieve intensity distribution, which is designed for example as a top hat distribution. However, there is also the possibility that the output-side intensity distribution corresponds to or equals the input-side intensity distribution, wherein the beam quality of the light beam can then be improved by the device according to the invention.

The periodically repeating interference patterns resulting from the interference effects form local intensity intensities which are spaced apart from one another in the region of the second lens array. Advantageously, the distance corresponds to this local

I ntensitätsmaxima to each other the center distance of the lenses of the second lens array to each other.

There is the possibility that the lenses of the first lens array and / or the lenses of the second lens array are each designed in such a way, in particular in each case in their edge regions such

Curvature that thereby diffraction-related effects are reduced. In this case, the lenses may have a cross-section in a middle region, which essentially corresponds to a second-order aspherical cross-section, such as, for example, a hyperbolic or a parabolic cross-section.

Furthermore, the lenses can have a cross-section in their edge regions that deviates from a second-order aspherical cross-section. As a result of this design of the lenses of the lens arrays, a very uniform top hat profile of the output-side intensity distribution can be achieved. According to a preferred embodiment of the present invention it can be provided that the device comprises a filter unit for reducing the diffraction factor M ^{2 of} the light beam to be formed. This filter unit can be designed as a Fourier filter unit. This can, for example, the

Filter unit comprising second and third lens means for the double Fourier transform of the light beam, which are arranged such that the output-side Fourier plane of the second lens means corresponds to the input-side Fourier plane of the third lens means. Furthermore, the filter unit a

Include aperture diaphragm, which is net angeord net in the output side Fourier plane of the second lens means and / or in the input-side Fourier plane of the third lens means. Inhomogeneities in the intensity distribution behind the second lens array will usually repeat several times periodically. These

Periodicity may arise from the fact that the first and the second lens array are periodic, their periodicities being correlated by the superimposition in the region of the second lens array. This effect occurs in particular when the light of the light beam to be formed is spatially coherent or at least spatially partially coherent. The periodicity can then cause strong diffraction effects. The inhomogeneities in the intensity distribution behind the second lens array are diffracted by the first Fourier transformation into the zeroth, the first and further diffraction orders and can be filtered out of the light beam by a spatial filter such as the aperture stop. This further improves the quality of the intensity distribution. For example, only the zeroth order may be passed through the aperture stop and the first and higher orders filtered out of the aperture stop. Or the zeroth and first order are allowed through and the second as well as higher orders are filtered out. There is the possibility that the first lens means and / or the second lens means and / or the third lens means each comprise a lens or a lens array or a plurality of lenses or lens arrays. It can be provided that the lenses of the at least one lens array of the first, second or third

Lens means have a pitch, which differs from the center distance of the first lens array and / or the distance of local intensity maxima before the second lens array to each other. Due to the different center distances can optionally on arranged behind the lens arrays lenses for

Overlay is omitted because this function can be transferred to the lens or the array.

According to claim 22 it is provided that in the resonator, a device according to the invention is arranged to influence the exiting laser beam intracavity. This can prevent the laser device from oscillating in undesired modes, so that a laser beam with a very small diffraction factor M ² can be generated.

It can be provided that the emerging laser beam has a top hat profile corresponding intensity distribution.

As a result, the laser beam is particularly suitable for applications such as material processing or the like.

Alternatively, it may be provided that the exiting laser beam has a Gaussian profile corresponding intensity distribution, wherein the laser radiation in the interior of the resonator at least partially has a top hat profile corresponding intensity distribution. By an at least partially top hat-shaped intensity profile in the interior of the resonator, the efficiency of the laser can be increased. 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 with schematic intensity distributions of a light beam to be formed at different locations of the device;

2 shows a schematic side view of a second embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

Fig. 3 is a schematic side view of a third

Embodiment of a device according to the invention with schematic intensity distributions of a to be formed

Light beam at different locations of the device;

Fig. 4 is a schematic side view of a fourth

Embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

Fig. 5a is a schematic side view of a fifth

Embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

5b shows a detailed view of the embodiment according to FIG. 5a;

FIG. 5c shows a detailed view according to the arrow Vc in FIG. 5b; FIG. 6a shows a schematic side view corresponding to FIG. 5b of a sixth embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

FIG. 6b shows a detail view according to the arrow VIb in FIG. 6a; FIG.

7a shows a schematic side view corresponding to FIG. 5b of a seventh embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

Fig. FIG. 7b shows a detail view according to the arrow VI Ib in FIG. 7a; FIG.

FIG. 7c shows a detail view according to the arrow VI Ic in FIG. 7a; FIG.

Fig. 8a is a Fig. 5b corresponding schematic side view of an eighth embodiment of the invention in accordance

Device with schematic intensity distributions of a light beam to be formed at different locations of the device;

8b is a detail view according to the arrow VI I Ib in FIG. 8a;

Fig. 9a a Fig. 5b shows a corresponding schematic side view of a ninth embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

Fig. FIG. 9b shows a detail view according to the arrow IXb in FIG. 9a; FIG. 10a a schematic side view corresponding to FIG. 5b of a tenth embodiment of a device according to the invention with schematic intensity distributions of a light beam to be formed at different locations of the device;

Fig. 10b is a detail view according to the arrow Xb in Fig. 10a.

For better orientation in each case a Cartesian coordinate system is shown in the figures.

The illustrated in Fig. 1 embodiment of a device according to the invention comprises in the propagation direction of a to be formed

Light beam or in the positive Z-direction behind a first lens array 1, first lens means 3, a second lens array 2 and a filter unit 4. The filter unit 4 has in the Z direction behind the other second lens means 5, an aperture diaphragm 7 and third lens means 6.

In the Z direction in front of the first lens array 1, in FIG. 1 shows a Gaussian intensity distribution 8, which is intended to schematically symbolize an incident light beam with a Gaussian profile, such as a typical laser beam. In the embodiment shown, the first lens array 1 comprises a substrate which has cylindrical lenses 9 arranged side by side on its exit side in the X direction, with cylinder axes extending in the Y direction. There is the possibility that cylindrical lenses are also arranged on the entrance side of the substrate, the cylinder axes of which extend in the X direction.

Furthermore, there is the possibility that the first lens array 1 comprises two or more substrates instead of a substrate, on each of which lenses, in particular cylindrical lenses, are arranged Cylinder axes can be aligned parallel and / or perpendicular to each other.

Through the first lens array 1, the light beam to be formed is subdivided into a plurality of sections which each have an intensity distribution which is dependent on the shape of the individual cylindrical lenses 9. The intensity distributions resulting from the passage through the cylindrical lenses 9 are superimposed by the first lens means 3 in the region of the second lens array 2 or shortly before it. The first lens means 3 may be formed as a single lens as shown or as a system of multiple lenses. In this case, the distance between the first lens array 1 and the first lens means 3 may correspond to the sum of the focal lengths of the first lens array 1 and the first lens means 3, so that the first lens array 1 and the first lens means 3 form a telescope or a telescope-like arrangement.

Furthermore, the distance between the second lens array 2 and the first lens means 3 may correspond to the sum of the focal lengths of the second lens array 2 and the first lens means 3, so that the second lens array 2 and the first lens means 3 are also one

Telescope or form a telescope-like arrangement.

The first lens means 3 thus form a telecentric arrangement with the lens arrays 1, 2. Furthermore, the first lens means 3 are arranged such that in the output-side focal plane of the lens means 3 a Fourier transformation of the input side

Focal plane of the lens means 3 is formed.

Due to the superimposition of the individual sections or partial beams of the light which has passed through the cylindrical lenses 9, in the In the case of coherent or partially coherent light, strong interference effects occur. The reference numeral 10 designates in FIG. 1 an intensity distribution or a field distribution which may arise shortly before or in the region of the second lens array 2. This intensity distribution 10 has interference patterns resulting from the overlay, which are periodic and repeat the input intensity distribution on a different scale several times. The envelope of this periodically repeating intensity distribution still has the desired predetermined intensity distribution, such as a top-hat profile.

The second lens array 2 comprises in the illustrated embodiment, two substrates 1 1, 12, of which the first substrate 1 1 arranged on its inlet side and the second substrate 12 on its exit side in the X direction side by side

Cylindrical lenses 13, 14 having extending in the Y direction cylinder axes. There is the possibility that cylinder lenses are likewise arranged on the exit side of the first substrate 11 and / or on the entry side of the second substrate 12, whose cylinder axes extend in the X direction. Furthermore, there is the possibility that the second lens array 2 instead of two substrates 1 1, 12 comprises only one substrate on which on the entrance and / or on the exit side lenses, in particular cylindrical lenses are arranged, the cylinder axes aligned parallel and / or perpendicular to each other could be .

The interference patterns resulting in periodically repeating interference patterns 10 form local intensity intensities spaced from one another in the region of the second lens array 2. Advantageously, the distance of these local intensity maxima from one another corresponds to the center distance Cylindrical lenses 13 and / or 14 of the second lens array 2 in the X direction to each other. This can be achieved in particular by the fact that

F * λ

P =

is selected, where P 'is the center distance of the cylindrical lenses 13 and / or 14 of the second lens array 2. This center distance P 'also corresponds to the width of the cylindrical lenses 13 and / or 14 of the second lens array 2 in the X direction. F denotes the focal length of the first lens means 3. λ is the wavelength of the light beam to be formed. P is the pitch of the cylindrical lenses 9 of the first

Lens arrays 1 in the X direction, which corresponds to the width of the cylindrical lenses 9 of the first lens array 1 in the X direction.

The second lens array 2 is used to straighten the interference pattern of the intensity distribution 10 as possible and possibly only to maintain the envelope. The cylindrical lenses 13, 14 of the second lens array 2 can be connected to the

Input intensity distribution have adapted form. The intensity distribution 15 or field distribution resulting behind the second lens array has inhomogeneities in the illustrated exemplary embodiment, which repeat themselves periodically several times. This periodicity may result from the fact that the first and the second lens array 1, 2 are periodic, their periodicities being correlated by the superposition in the region of the second lens array 2. This periodicity can cause strong diffraction effects, especially with coherent or at least partially coherent light. Due to these diffraction effects, the filter unit 4 is able to filter out the inhomogeneities from the intensity distribution or from the field distribution of the light beam to be formed. For this purpose, the second lens means 5, the aperture diaphragm 7 and the third lens means 6 are accommodated in a Fourier arrangement in the device. This means that each of the lens means 5, 6 effects a Fourier transformation of the light beam to be formed, wherein the aperture diaphragm 7 is arranged in the output-side Fourier plane of the second lens means 5 and / or in the input-side Fourier plane of the third lens means 6. This can be achieved, for example, in that the distance between the second lens means 5 and the aperture diaphragm 7 corresponds to the focal length of the second lens means 5 and / or that the distance between the third lens means 6 and the aperture diaphragm 7 corresponds to the focal length of the third lens means 6.

There is the possibility that the second lens means 5 and / or the third lens means 6 each consist of a lens as shown, or else comprise a plurality of lenses.

In FIG. 1, reference numeral 16 schematically indicates an intensity distribution or field distribution resulting from a single Fourier transformation by means of the second lens means 5 in the region of the aperture diaphragm 7. In this case, a peak 17 is arranged in the middle, which corresponds to a zeroth order of the Fourier-transformed intensity distribution 16. Laterally outward or in the positive and negative X direction offset from the zero-order peak 17, two peaks 18 corresponding to the first order of the Fourier-transformed intensity distribution 16 are arranged. Spaced laterally outwards relative to the peaks 18 are peaks 19, 20 which correspond to higher orders of the Fourier-transformed intensity distribution 16. The Aperture diaphragm 7 is dimensioned in the X direction and possibly also in the Y direction in such a way that only portions of the light which correspond to the peak 17 of the zeroth order are transmitted.

It is important to note at this point that the periodicity in the field distribution before and / or behind the second lens array 2 is a prerequisite for the possibility of influencing the field distribution by means of the filter unit 4. A non-periodic or homogeneous field distribution before and / or behind the second lens array 2 does not offer the possibility with which

Filter unit 4 to filter out portions of light corresponding to higher orders than, for example, the zeroth order. This filtering out filters out the periodic component from the field distribution.

By caused by the third lens means 6 second

Fourier transformation of the light beam to be formed is then transferred to a state in which it has an intensity distribution 21 and field distribution, as shown on the right edge of FIG. 1. This intensity distribution 21 corresponds to a top hat profile, in which only in the lateral

Flanks light artifacts occur that arise due to the limited numerical aperture of the lenses or the aperture 7. However, the intensity profile 21 is defined very precisely and can be converted by simple means into a very homogeneous top hat profile.

In FIGS. 2 to 10 b, the same parts are provided with the same reference numerals as in FIG. 1. Fig. 2 shows an embodiment of the device according to the invention, in which behind the filter unit 4, a Schmidt plate 22 and imaging means 23 are arranged. By means of these additional refractive means, the intensity distribution 21 can be converted into an intensity distribution 24 corresponding to a top hat profile.

Fig. 3 shows an embodiment of the device according to the invention, in which behind the second lens array 2 serving as a field lens imaging means 25 are arranged. By means of these additional refractive means, instead of the intensity distribution 21 behind the filter unit 4, a top hat

Profile corresponding intensity distribution 26.

4 shows an embodiment of the device according to the invention, in which the cylindrical lenses 9 of the first lens array 1 and, under certain circumstances, the cylindrical lenses 13, 14 of the second lens array 2 are shaped in such a way that the interference-related

Artifacts on the flanks of the intensity distribution do not arise. Rather, the light beam to be formed has an intensity distribution 27 behind the filter unit 4, which corresponds to a top hat profile. The cylindrical lenses 9 and optionally also the cylindrical lenses 13, 14 can be shaped in this case, like the cylindrical lenses described in DE 10 2004 020 250 A1. These cylindrical lenses each have such a curvature in their edge regions that diffraction-related effects are thereby reduced. In particular, the cylindrical lenses in a middle region have a cross-section which is substantially an aspherical cross-section second

Order, such as a hyperbolic or a parabolic cross section corresponds, wherein the cylindrical lenses at the same time in their edge regions have a cross section which differs from a second-order aspherical cross section. It can be seen from FIG. 4 that the intensity distribution 10 in front of the second lens array 2 already has a somewhat different envelope than that of the intensity distribution 10 achieved in FIGS. 1 to 3. In particular, the envelope is slightly lower at the lateral edges. This change in the intensity distribution 10 in front of the second lens array 2 ultimately contributes to the generation of the output hat-related intensity distribution 27 corresponding to a top hat.

FIGS. 5a to 5c show an embodiment in which the first lens means are formed by two separate lenses 3a and 3b. Even with the use of two separate lenses 3a, 3b can also be provided a telescopic arrangement or telescope-like arrangement. In particular, in this embodiment, the system of the lenses 3a, 3b with the lens arrays 1, 2 form a telecentric arrangement. Furthermore, the lenses 3a, 3b are arranged such that in the output side focal plane of the

Systems from the lenses 3a, 3b, a Fourier transformation of the input-side focal plane of the system of the lenses 3a, 3b is formed. The output-side focal plane or Fourier plane of the system of the lenses 3a, 3b corresponds to the input-side focal plane of the second lens array 2.

FIG. 5b and FIG. 5c show that local intensity maxima 28 which are spaced apart from one another in the X direction in front of the second lens array 2 or even in front of the second lens 3b, each having a Gaussian profile in accordance with the intensity distribution 10 also drawn. In Fig. 5a and Fig.

5b illustrates that the envelope 29 of the intensity distribution 10 can correspond to a top hat profile.

In the embodiment according to FIGS. 5a to 5c, the second lens array 2 comprises only one substrate 12, but can also be like the one already described embodiments have two or more substrates.

The first lens 3a can cause the Fourier transformation, whereas the second lens 3b causes the telecentricity of the system. If the second lens 3b is omitted with the same arrangement of the first lens 3a, the intensity distribution 10 is not changed. Only the mean propagation directions of the partial beams emanating from the local intensity maxima 28 will no longer be parallel to one another.

The embodiment according to FIGS. 6a and 6b therefore shows a

Device in which the second lens 3b has been omitted and replaced by a lens array 30. The lenses of this lens array 30 are designed as cylindrical lenses 31 with cylinder axes extending in the Y direction. This lens array 30 can also be used as part of the lens array 2 according to the embodiments according to FIGS

Fig. 4 are considered. However, the lens array 30 has a center pitch P _{1 of} the individual cylindrical lenses 31, which is smaller than the distance P _{2 of} the local intensity maxima 28 to one another. By this choice of the center distance Pi, the parallelism of the intensity of the local I ntensitätsmaxima 28 outgoing partial beams can be ensured. In contrast to the embodiments according to FIGS. 5 a to 5 b. 5c are smaller due to the cylindrical lenses 31 which are very small compared to the lens 3b.

In the embodiment according to FIGS. 7 a to FIG. 7c, the first lens 3a is also replaced by a lens array 32. The lenses of this lens array 32 are designed as cylindrical lenses 33 with cylinder axes extending in the Y direction. The lens array 32 has a pitch P _{3 of} the individual cylindrical lenses 33, the is smaller than the center distance P _{4 of} the cylindrical lenses 9 of the first lens array 1 and thus the local intensity maxima 34 generated by these to each other. By this choice of the center distance P ₃ , the function of the lens _{3 a} can be realized by the lens array 32. Again, by the small

Extension of the cylindrical lenses 33 compared to the first lens 3a reduces the aberrations.

The embodiment according to FIGS. 8a and 8b differs from that according to FIGS. 5a to 5c only in that the distance between the second lens means 5 of the filter unit 4 and the second lens array 2 is somewhat smaller. The second lens means 5 according to FIGS. 8a and 8b converge the partial beams emanating from the local intensity maxima 28.

This function of the second lens means 5 according to FIG. 8a becomes in the embodiment according to FIG. 9a and FIG. 9b through the lens array

30 ', which differs from the lens array 30 according to FIGS. 6 a and 6 b only in that the center distance Pi' of the cylindrical lenses 31 'is slightly smaller than the center distance Pi of the cylindrical lenses 31. As a result, the partial beams emanating from the local intensity maxima 28 do not run parallel to one another but already converge a little. With this embodiment, the lens means 5 can thus be saved compared with those shown in FIGS. 6a and 6b.

The embodiment according to FIGS. 10a and 10b corresponds to that according to FIGS. 9a and 9b, except for the fact that the first lens

3a has been replaced by the lens array 32 as in the embodiment of FIGS. 7a and 7b. Thus, there is a device in which can be largely dispensed with large lenses and the Beam shaping is achieved almost exclusively by micro-scanning lenses of the individual lens arrays 1, 32, 30 ', 2.

It is possible to form or change the shape of the individual cylindrical lenses 9, 33, 31, 14 in such a way that no top-hat distribution but an arbitrary predefinable intensity distribution arises at the output of the device.

Claims

claims: 1 . Apparatus for shaping a light beam, comprising a first lens array (1) through which the light beam to be formed can pass, - A second lens array (2), in the propagation direction of the Light beam is disposed behind the first lens array (1) so that light passed through the first lens array (1) can pass through the second lens array (2), characterized in that the device comprises first lens means (3) arranged between the first and the second lens array (1, 2) and portions of the light passed through the first lens array (1) in front of the second lens array (2) or in the region of the second lens array (2) can overlap with each other. 2. Apparatus according to claim 1, characterized in that the first lens means (3) and the first lens array (1) form a telescope or a telescope-like arrangement. 3. Device according to one of claims 1 or 2, characterized in that the first lens means (3) and the first lens array (1) are arranged such that the output-side focal plane of the first lens array (1) and the input-side focal plane of the first lens means ( 3) correspond to each other or are arranged approximately in the same area. 4. Device according to one of claims 1 to 3, characterized in that the first lens means (3) and the second lens array (2) form a telescope or a telescope-like arrangement. 5. Device according to one of claims 1 to 4, characterized in that the first lens means (3) and the second lens array (2) are arranged such that the output-side focal plane of the first lens means (3) and the input-side focal plane of the second lens array ( 2) correspond to each other or are arranged approximately in the same area. 6. Device according to one of claims 1 to 5, characterized in that the first lens array (1) and / or the second lens array (2) has a first and a second optically functional interface, which are spaced apart in the propagation direction of the light beam to be formed wherein an array of lenses is formed on each of the interfaces. 7. Device according to one of claims 1 to 6, characterized in that the lenses of the first lens array (1) and / or the lenses of the second lens array (2) are designed as cylindrical lenses (9, 13, 14). 8. The device according to claim 7, characterized in that d the cylinder axes of the arranged on the first and on the second optically functional interface cylinder lenses (9, 13, 14) of the first lens array (1) and / or the second lens array (2) are aligned perpendicular or parallel to each other. 9. Device according to one of claims 1 to 8, characterized in that the lenses of the first lens array (1) and / or the lenses of the second lens array (2) are each designed in such a way, in each case in their edge regions have such a curvature that thereby diffraction-related effects are reduced. 10. The device according to claim 9, characterized in that the lenses in a central region have a cross section which substantially corresponds to a second-order aspherical cross section, such as a hyperbolic or a parabolic cross section. 1 1. Device according to one of claims 9 or 10, characterized in that the lenses have in their edge regions a cross section which differs from an aspherical cross section of the second order. 12. Device according to one of claims 1 to 1 1, characterized in that the device comprises a filter unit (4) for reducing the diffraction factor M ^{2 of} the light beam to be formed. 13. The apparatus according to claim 12, characterized in that the filter unit (4) is designed as a Fourier filter unit. 14. The device according to claim 13, characterized in that the filter unit (4) comprises second and third lens means (5, 6) for the double Fourier transform of the light beam, which are arranged such that the output side Fourier plane the second lens means (5) corresponds to the input-side Fourier plane of the third lens means (6). 15. Device according to one of claims 12 to 14, characterized in that the filter unit (4) comprises an aperture diaphragm (7). 16. The apparatus according to claim 15, characterized in that the aperture diaphragm (7) in the output side Fourierbene the second lens means (5) and / or in the input side Fourierbene the third lens means (6) is arranged. 17. Device according to one of claims 1 to 16, characterized in that the first lens means (3) and / or the second lens means (5) and / or the third lens means (6) each have a lens or a lens array (30, 32) or a plurality of lenses (3a, 3b) or lens arrays (30, 32). 18. The device according to claim 17, characterized in that the lenses of the at least one lens array (30, 32) of the first, second or third lens means (3, 5, 6) have a center distance (Pi, Pi ', P ₃ ), the differs from the center distance (P ₄ ) of the first lens array (1) and / or from the distance (P ₂ ) of local intensity maxima (28) in front of the second lens array (2). 19. Device according to one of claims 1 to 18, characterized in that the device comprises additional refractive means, the influence on the lateral edges of the Intensity distribution of the light beam to be formed can influence. 20. The device according to claim 19, characterized in that the additional refractive means comprise a Schmidt plate (22) and / or imaging means (23, 25). 21. Device according to one of claims 19 or 20, characterized in that the additional refractive means behind the second lens array (2) or behind the filter unit (4) are arranged. 22. A laser device comprising a resonator from which a laser beam can emerge, characterized in that in the resonator, a device according to one of claims 1 to 21 is arranged to influence the exiting laser beam intracavity can. 23. A laser device according to claim 22, characterized in that the exiting laser beam has a top hat profile corresponding I ntensitätsverteilung. 24. Laser device according to claim 22, characterized in that the exiting laser beam has a Gaussian profile corresponding I ntensitätsverteilung, the laser radiation in the inside of the resonator I at least partially corresponding to a top hat profile I ntensitätsverteilung has. 25. A method for shaping a light beam, in particular a spatially coherent or spatially partially coherent light beam, characterized by the following method steps: - Generating an at least in one direction (X) periodic Field and / or intensity distribution of the light beam through at least a first lens array (1) and in the propagation direction (Z) arranged behind this first lens means (3); Filtering out at least part of the periodicity by a filter unit (4) designed as a Fourier filter unit, which filters out orders of a predetermined order from the light beam. 26. The method according to claim 25, characterized in that the periodic field and / or intensity distribution of the light beam before passing through the filter unit (4) by at least a second, in the propagation direction (Z) behind the first lens means (3) arranged lens array ( 2) is at least partially straightened.