WO2012084425A1

WO2012084425A1 - Stripline laser amplifier and laser arrangement with a stripline laser amplifier

Info

Publication number: WO2012084425A1
Application number: PCT/EP2011/071240
Authority: WO
Inventors: Hermann Hage; Jörg Porath
Original assignee: Rofin-Sinar Laser Gmbh
Priority date: 2010-12-23
Filing date: 2011-11-29
Publication date: 2012-06-28
Also published as: DE102010064147B4; DE102010064147A1

Abstract

A stripline laser amplifier contains a plurality of electrodes (4a-c), which are arranged stacked one above the other and extended areally, the flat sides of said electrodes lying opposite one another, and in each case one narrow discharge space (6a, b) being formed between said electrodes, in which a carbon dioxide (CO₂)-containing laser gas is located, wherein in each case one folding mirror (10a, b) is arranged at the end sides (8a, b) of each discharge space (6a, b) and the discharge spaces (6a, b) are connected optically one behind the other with a coupling mirror arrangement (12).

Description

description

Band conductor laser amplifier and laser arrangement with a band conductor laser amplifier

The invention relates to a stripline laser amplifier and a laser arrangement with a stripline laser amplifier.

The extraction of high power from a laser oscillator is due to the associated increase in size of the Laseros ^¬ cillator associated with a variety of limitations, for example, in terms of beam quality, beam stability and the pulse length, which generally increases the minimum achievable pulse length with increasing output power. In order to achieve a high laser power with good beam quality, high stability of the optical properties and the shortest possible pulse length, it is known to produce a laser beam with a relatively small laser oscillator and low output power and this with the aid of one or more series-connected Amplify laser amplifier. A band conductor or slab laser oscillator is a laser oscillator known, for example, from EP 0305893 A2 or US Pat. No. 4,719,639 A, whose resonator is a combination of a waveguide resonator and an unstable resonator of the positive or negative branch. In such a band conductor laser oscillator is located

Carbon dioxide containing CO ₂ gas mixture in a narrow discharge formed between two flat plate-shaped electrodes formation space. By applying a high-frequency electromagnetic field, the gas mixture located between the electrodes is excited. A resonator mirror is arranged in each case opposite the end faces of the narrow parallelepiped discharge space formed in this way. The resonator mirrors form in a direction parallel to the narrow side of the Entla ^¬ dung space unstable confocal resonator with a free beam propagation. Transversely to this direction, the propagation conditions of the electromagnetic radiation arising within the discharge space are determined by the waveguide properties of the electrodes.

Such shaped discharge space can also be used as a laser amplifier when are ^¬ arranged on the front sides of the discharge space instead of resonator mirrors folding mirrors, which deflect an incoming parallel at the edge of the discharge space to the long side into the discharge space laser beam zigzag so that it repeatedly the Traversing the discharge space and experiencing a gain. A laser arrangement in which a strip laser amplifier is connected downstream of a laser oscillator is known, for example, from DE 10 2009 024 360 A1.

To achieve a high gain with a stripline laser amplifier, it is basically possible to increase the electrode area accordingly. An enlargement of the electrode surfaces, however, is only possible to a limited extent since the production of very large electrodes encounters production-related limits with the accuracy required with regard to their planicity. In addition, such a scaling leads to a laser structure with undesirable in practice longitudinal ^¬ or transverse expansions. The invention is based on the object to provide a Bandlei ^¬ ter laser amplifier with which a high gain can be achieved with a compact design. In addition, the invention is based on the object to provide a laser array with a ribbon conductor laser amplifier, with which it is possible to achieve a high performance in a likewise compact structure.

As regards the strip conductor laser amplifier, the object is achieved according to the invention solved by the features of the Patenanspru ^¬ ches 1. According to these features, the Bandleiter- laser amplifier comprises a plurality of stacked arranged areally extended and with their flat sides of opposed electrodes between which a narrow discharge chamber is formed, in which a

Carbon dioxide CO ₂ containing laser gas is. A folding mirror is arranged in each case on the end sides of each ^¬ discharge space and discharge spaces are connected with a coupling Spie ^¬ gelanordnung optically behind the other.

By means of such a series connection of narrow discharge spaces stacked one above the other, a high gain with technologically controllable electrode surfaces can be achieved with a compact construction of the stripline laser amplifier in accordance with the number of discharge spaces stacked one above the other. Thus, a resonator surrounding Vakuumge ^¬ fäß must be only slightly enlarged in its height corresponding to the number of superposed in the stack electrodes. In addition, the necessary for holding the resonator substructure need not be increased, as would be the case in next ^¬ each other or arranged one behind another laser amplifiers. A particularly compact construction is achieved if adjacent discharge spaces are spatially separated from each other by a common electrode. A further advantage of such an arrangement is also that the intermediate electrodes experience a symmetrical thermal load, ie both flat sides are thermally loaded in the same way, so that a bending caused by different thermal load ^¬ bending of these electrodes can no longer occur.

In particular, flat mirrors are provided as folding mirrors, the mirror surfaces of which are preferably inclined slightly, i. are arranged obliquely to each other to exclude optical feedback and to ensure that the propagating between the folding mirrors laser beam is not reflected back into itself.

With regard to the laser arrangement, the object is achieved according to the invention with the features of claim 4.

According to these features, the laser arrangement comprises a first and at least one second discharge space, each of which is stacked between two stacked and flat electrodes and opposite to each other, in which a laser gas containing carbon dioxide CO ₂ is located. Is at the end faces of a first discharge space in each case a resonator mirror being ^¬ assigns that form an unstable resonator in a direction parallel to the flat sides oriented direction, wherein at the end faces of the at least one second discharge space depending ^¬ weils a folding mirror is arranged, and first and second discharge space with a coupling mirror arrangement optically mitei- are coupled together. In other words, the first Entla ^¬ formation space forms a strip conductor laser oscillator, together with the resonator mirrors, which is used during at least an overlying second discharge space as Bandleiter- laser amplifier.

In this way, it is possible to use a laser array herzustel ^¬ len, which generates a laser beam with high power with a compact structure and with technologically controllable electrode surfaces.

For further explanation of the invention reference is made to the embodiments illustrated in the figures. Show it :

1 shows a stripline laser amplifier according to the invention in a schematic side view,

2 and 3 each have a parallel to the electrode surfaces extending cross section through the band conductor laser amplifier of FIG. 1 in different sectional planes,

4 shows a laser arrangement according to the invention also in a schematic view on the longitudinal side,

Fig. 5, the laser arrangement shown in Fig. 4

Cross section parallel to the electrode surfaces.

1, three electrodes 4a, 4b and 4c are stacked in a stack in a band conductor laser amplifier according to the invention on a common base 2. Zvi ^¬ rule the electrodes 4a and 4b and between the electrodes 4b and 4c, respectively, a narrow discharge space 6a and 6b is formed, in which a carbon dioxide CO2 containing

Lasergas is located. In the discharge space 6a, a laser beam LSi _{n is} coupled to an end face 8a, which is generated by an external laser oscillator, not shown in the figure and propagates parallel to the longitudinal side of the discharge ^¬ space 6a.

Opposite the end faces 8a of the discharge space 6a folding mirrors are arranged 10a, which reflect the propagating within the Entla ^¬ dung space 6a and emerging on the end faces 8a laser beam LS in the discharge space 6a and b, so that this discharge space 6a between the opposed Folded mirrors 10a repeatedly zigzag passes through and is amplified in each pass until it exits at a lateral edge of the Entla ^¬ training space 6a and a coupling mirror assembly 12 which couples the laser beam LS in the overlying discharge space 6b, he between the opposite

End faces 8b of this discharge space mirror 6b arranged folding ^¬ 10b also traversed repeatedly until it is coupled out of the discharge space 6b as emerging reinforced laser beam LS _o ut. The two superposed discharge chambers 6a, b are accordingly optically connected in series by the coupling ^¬ mirror assembly 12.

In the embodiment of the figure, two discharge spaces b are arranged one above the other. In principle, however, such discharge spaces can be arranged one above the other.

2 illustrates the zigzag course of the laser beam LSi _n coupled into the discharge space 6a. These are In the exemplary embodiment, the mirror surfaces of both folding mirrors 10a are arranged obliquely to a system axis 14 extending in the longitudinal direction parallel to the flat ^{sides of} the electrodes 4a, b. In principle, however, the mirror surface of one of the two folding mirrors 10a may be arranged perpendicular to this system axis 14. It is only important that the mirror surfaces of the two folding mirrors 10a are not arranged parallel to one another but slightly inclined relative to one another or at an angle to one another.

After repeatedly traversing the discharge space 6a of the exiting laser beam LS is coupled from the coupling mirror assembly 12 in the overlying discharge space 6b, he, as shown in Fig. 3 is also repeatedly zigzag between the equally inclined folding mirrors 10b runs through until he also at the edge of a the faces exits.

According to FIG. 4, three electrodes 4a, b, c are likewise arranged one above the other in a stack in a laser arrangement, so that a first discharge space 6a and a second discharge space 6b are formed, which are arranged one above the other. In contrast to the example shown in Fig. 1-3 execution ^¬ example, however, 6a resonator mirror 20 are arranged so that a strip conductor laser oscillator is formed over the end faces 8a of the first discharge space. The laser beam LS generated in this band-conductor laser oscillator is decoupled from the unstable resonator formed in this way and coupled via the coupling mirror arrangement 12 into the discharge space 6b located above it, on the end faces 8b of which folding mirrors 10b are respectively arranged, so that the discharge space 6b coupled laser beam LS this multiple traverses zigzag and is thereby reinforced. With walls ^¬ ren words. In the example shown in Figure 4 Construction laser oscillator and strip conductor laser amplifier are integrated into a stack, is which is in the exemplary embodiment is a negative branch resonator as a laser oscillator is also a strip conductor laser oscillator provided inside focus F acts, as illustrated by the in Fig. 5 Darge ^¬ presented beam path and the concave resonator 20. In this embodiment as well, a plurality of stripline laser amplifiers can be arranged in a stack over the stripline laser oscillator.

As an alternative to the flat folding mirrors shown in the exemplary embodiments, folding mirrors with slightly concave or convexly curved mirror surfaces can also be provided.

Claims

claims

1. stripline laser amplifier having a plurality of stacked arranged extensively and with their flat sides opposite each other electrodes (4a-c), between each of which a narrow discharge space (6a, b) is formed, in which a carbon dioxide CO ₂ containing laser gas is wherein at the end faces (8a, b) of each Ent ^¬ cargo space (6a, b) each include a folding mirror (10a, b) is angeord ^¬ net and the discharge spaces (6a, b) are connected with a coupling Spie ^¬ gelanordnung (12) optically behind the other are.

2. stripline laser amplifier according to claim 1, wherein the adjacent discharge spaces (6a, b) by a common electrode (4b) are spatially separated from each other.

3. stripline laser amplifier according to claim 1 or 2, wherein the folding mirror (10 a, b) have flat mirror surfaces which are arranged obliquely to each other.

4. Laser arrangement with a band conductor laser amplifier having a first and at least one second stacked between two stacked out ^¬ stretched and with their flat sides opposite electrodes (4a-c) formed narrow discharge space (6a, b), in which a Laser gas (LG) containing carbon dioxide CO ₂ is located, wherein on the end faces (8a) of the first discharge space (6a) in each case a resonator mirror (20) is arranged, which form an unstable resonator in a direction parallel to the flat sides direction, and at the front ends (8b) of the second discharge space (6b) in each case a folding mirror (10b) is arranged, wherein the first and second discharge space (6a, 6b) and second discharge spaces (6b) with a coupler gel ^¬ gelanordnung (12) are optically connected in series.

5. A laser arrangement according to claim 4, wherein the adjacent discharge spaces (6a, 6b) by a common electrode (4b) are spatially separated from each other.