Method and system for generating different laser radiation

Abstract

The invention relates to a method for generating different laser radiation in a laser resonator, comprising the method steps of: generating first laser radiation using a first laser medium; changing the position of the first laser medium; changing the position of a second laser medium; and generating second laser radiation using the second laser medium; wherein the first and the second laser medium differ in terms of a physical property. The invention further relates to a device for generating different laser radiation, comprising a laser resonator; a first laser medium which can be arranged in the beam path of the laser resonator; a second laser medium which can be arranged in the beam path of the laser resonator; and a positioning device which is suitable for positioning the first and / or second laser medium in the beam path, wherein the first and the second laser medium differ in terms of a physical property.

Description

[0001] METHOD AND SYSTEM FOR GENERATING DIFFERENT LASER RADIATION

[0002] The invention relates to a method for generating different laser radiation in a laser resonator, comprising the method steps of generating a first laser radiation with a first laser medium, changing the position of the first laser medium, changing the position of a second laser medium, and generating a second laser radiation with the second laser medium, wherein the first and second laser media differ in a physical property. The invention further relates to a device for generating different laser radiation, comprising a laser resonator, a first laser medium that can be arranged in the beam path of the laser resonator, a second laser medium that can be arranged in the beam path of the laser resonator, and a positioning device that is suitable for positioning the first and / or second laser medium in the beam path, wherein the first and second laser media differ in a physical property.

[0003] State of the art

[0004] Certain applications in laser material processing and marking, as well as in other fields such as spectroscopy, require the use of lasers with tunable, i.e., variable, wavelengths. However, such tunable lasers often emit insufficient laser power. Therefore, higher-power, non-tunable lasers are used. Changing the wavelength of the emitted laser radiation requires changing the laser or the active laser medium. Changing the laser, however, often requires extensive, frequently manual, adjustment to ensure the beam paths of the respective lasers are consistent. Such adjustment is time-consuming and therefore costly.It is therefore an object of the present invention to provide a method for generating different laser radiation, which generates different laser radiation while simultaneously avoiding extensive adjustment. It is also an object of the present invention to provide a device for generating different laser radiation, which generates different laser radiation while simultaneously avoiding extensive adjustment.

[0005] The object is achieved by means of the method for generating different laser radiation according to claim 1. Advantageous embodiments of the invention are set out in the subclaims.

[0006] The inventive method for generating different laser radiation comprises four process steps: In the first process step, a first laser radiation is generated using a first laser medium. A laser medium, in the context of this document, is the active medium. The laser medium can be solid, liquid, or gaseous, among other things.

[0007] In the second method step, the position of the first laser medium is changed. In the third method step, the position of a second laser medium is changed. The positions of both laser media are preferably changed simultaneously, but can also be offset in time. Optionally, the position of the second laser medium is changed in such a way that the second laser medium, after the change in position, is arranged at the same location as the first laser medium before its position was changed. Likewise optionally, the position of the second laser medium is changed in such a way that the second laser medium, after the change in position, has the same optical axis as the first laser medium before its position was changed, in other words the optical axis of the first laser medium before its position was changed and the optical axis of the second laser medium after its position was changed are arranged in the same way.In the fourth method step, a second laser beam is generated using the second laser medium. The first laser medium is optionally deactivated and does not emit any first laser beam. According to the invention, the first and second laser media differ in one physical property.

[0008] In a further development according to the invention, the physical property in which the two laser media differ is a laser-optical property. In an optional embodiment of the invention, the physical property or the laser-optical property is the crystal type, crystal doping and other crystal properties, such as thermal properties and / or the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency, and / or the radiation emitted by the laser media differs from one another with regard to its power, pulsed or continuous wave operation, number and type of transverse modes, polarization (linear, circular), absorption linewidth, emission linewidth and / or wavelength.

[0009] The method according to the invention therefore enables a simple and rapid change of the emitted laser radiations in order to provide different laser radiations for different applications, wherein optionally the optical axes of the laser media emitting the laser radiations remain unchanged when changing the emitted laser radiations.

[0010] In an advantageous embodiment of the invention, the first laser medium is arranged in a first laser resonator and the second laser medium is arranged in a second laser resonator, wherein when the position of the first laser medium is changed, the position of the first laser resonator is changed and when the position of the second laser medium is changed, the position of the second laser resonator is changed. In a preferred embodiment, the laser medium can be arranged in a laser resonator which, for example, has one or two parallel or confocally arranged mirrors. This can, for example, also be achieved by a structure comprising a vapor-deposited crystal and a mirror. Furthermore, an output mirror can also be applied directly to the crystal, or a highly reflective mirror, or both, so that the crystal, in conjunction with the coatings applied to it, represents a laser resonator.Optionally, both mirror layers can be designed so that they are also transparent to the respective pump radiation. Furthermore, a so-called saturable absorber can be connected to the crystal, which generates passively Q-switched pulses. In this case, the output mirror or the highly reflective mirror is applied to the end face of the saturable absorber.

[0011] In a further development of the invention, by changing the position of the first laser medium, the first laser medium is removed from the active beam path of the laser resonator. The active beam path is determined in this document by the arrangement of the components of the laser resonator, e.g. arrangement and spacing of two oppositely arranged mirrors, and is independent of whether a laser medium arranged in a laser resonator emits laser radiation or not. In a further development, the active beam path is defined by any optical components arranged in the beam path of the laser radiation emitted by the laser resonator, e.g. lenses, prisms and / or gratings, or by the optical axes of the optical components, whereby it is also irrelevant whether the laser medium emits laser radiation or not.

[0012] In a further embodiment of the invention, by changing the position of the second laser medium, the second laser medium is positioned in the active beam path of the laser resonator. After positioning the second laser medium in the active beam path, the second laser radiation emitted by the laser resonator has the same beam path as the first laser radiation emitted by the laser resonator using the first laser medium. In a further embodiment of the invention, the first laser medium is pumped with pump radiation having a first pump wavelength and the second laser medium is pumped with pump radiation having a second pump wavelength, wherein the first pump wavelength can be different from the second pump wavelength. Different laser media usually require different pump wavelengths to achieve population inversion in the first and second laser medium.

[0013] In a further embodiment of the invention, the pump radiation with the first pump wavelength and the pump radiation with the second pump wavelength are generated by a pump medium, wherein the pump medium is suitable for generating pump radiation with different wavelengths. In a further configuration of the invention, the pump medium generates pump radiation with the first pump wavelength and pump radiation with the second pump wavelength. The first and second laser media can be pumped particularly effectively using only one pump medium, whose pump wavelength is optionally adjustable or has a correspondingly large spectral range.

[0014] In a further development of the invention, the position of the pump medium remains unchanged during the change in the position of the first laser medium and / or during the change in the position of the second laser medium. The pump medium is thus fixed and pumps the first and second laser medium in such a way that the pump medium pumps the first laser medium with a suitable first pump radiation and the second laser medium with a suitable second pump radiation.

[0015] In a further embodiment of the invention, the first laser medium is pumped with the pump radiation generated by a first pump medium and the second laser medium is pumped with the pump radiation generated by a second pump medium. In a further configuration of the invention, the first laser medium is pumped with the pump radiation generated by a first pump diode and the second laser medium is pumped with the pump radiation generated by a second pump diode. Each laser medium is pumped by a respective pump medium such that the first pump medium pumps the first laser medium with a suitable first pump radiation and the second pump medium pumps the second laser medium with a suitable second pump radiation. Each laser medium is pumped by one or more pump media, wherein the first pump medium(s) pump(s) the first laser medium with a suitable first pump radiation and the second laser medium with a suitable second pump radiation.If pumping occurs through multiple pump media, different arrangements are conceivable, such as pumping from both sides of the laser medium. Another arrangement could also consist of a laser pump module capable of directly emitting different pump wavelengths or, alternatively, being fiber-guided.

[0016] In a further embodiment of the invention, the position of the first pump diode is changed by changing the position of the first laser medium. The first pump medium is preferably arranged at a defined distance from the first laser medium and, along with the first laser medium, its position is also changed during the change in the position of the first laser medium.

[0017] In a further development of the invention, the position of the second pump diode is changed by changing the position of the second laser medium. The second pump medium is preferably arranged at a defined distance from the second laser medium and, along with the second laser medium, its position is also changed along with the second laser medium.

[0018] In a further embodiment of the invention, the radiation emitted by the first laser medium is offset from the radiation emitted by the second laser medium. The first laser medium and the second laser medium typically have different beam paths. The different beam paths are spaced apart from one another—the offset. Likewise, the beam path of the first laser medium before its position change can be offset from the beam path of the second laser medium after its position change.

[0019] The object is further achieved with the device according to the invention for generating different laser radiation. Further advantageous embodiments of the invention are also set forth in the subclaims.

[0020] The device according to the invention for generating different laser radiation has a laser resonator and a first laser medium that can be arranged in the beam path of the laser resonator, as well as a second laser medium that can be arranged in the beam path of the laser resonator. The laser resonator has a beam path that is defined by the optical elements, e.g. mirrors. The device also has a positioning device that is suitable for positioning the first and / or second laser medium in the beam path of the laser resonator. The first and second laser medium are preferably fixedly arranged on the positioning device; by moving the positioning device, the first and / or second laser medium is positioned in the beam path of the laser resonator such that the second laser medium, after the change in position, is arranged at the same location as the first laser medium before its change in position.Also optionally, the position of the second laser medium is changed such that the second laser medium, after the change in position, has the same optical axis as the first laser medium before its position change. The optical axis of the first laser medium before its position change and the optical axis of the second laser medium after its position change are thus arranged in the same way. According to the invention, the first and second laser medium differ in one physical property.

[0021] In an optional embodiment of the invention, the positioning device is designed with respect to its material in such a way that the positioning device, in addition to the positioning function, is also suitable and intended to dissipate the heat generated in the positioning unit.

[0022] In a further development according to the invention, the physical property in which the two laser media differ is a laser-optical property. In an optional embodiment of the invention, the first and second laser media differ in their crystal type, crystal doping and other crystal properties, such as the thermal properties and / or the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency, and / or the radiation emitted by the laser media with regard to power, pulsed or continuous wave operation, the number and type of transverse modes, the polarization (linear, circular), the absorption linewidth, the emission linewidth and / or the wavelength.

[0023] In one development of the invention, the first laser medium can be positioned in the active beam path and outside the active beam path of the laser resonator. In a further embodiment of the invention, the second laser medium can be positioned in the active beam path and outside the active beam path of the laser resonator. After the second laser medium is positioned in the active beam path, the second laser radiation emitted by the laser resonator has the same beam path as the first laser radiation emitted by the laser resonator via the first laser medium, and vice versa.

[0024] In a further embodiment of the invention, the first laser medium is arranged in a first laser resonator and the second laser medium is arranged in a second laser resonator, wherein the position of the first laser resonator is changed when the position of the first laser medium is changed, and the position of the second laser resonator is changed when the position of the second laser medium is changed. The laser medium can be arranged in a laser resonator which, for example, has one or two parallel or confocally arranged mirrors. The first and second laser media can also differ with regard to crystal type, crystal doping and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0025] In a further embodiment of the invention, the first laser medium can be pumped with pump radiation having a first pump wavelength, and the second laser medium can be pumped with pump radiation having a second pump wavelength, wherein the first pump wavelength differs from the second pump wavelength. Different laser media typically require different pump wavelengths to achieve population inversion in the first and second laser media.

[0026] In a further embodiment of the invention, the device comprises a pump medium, wherein the pump radiation having the first pump wavelength and the pump radiation having the second pump wavelength can be generated by this pump medium, and wherein the pump medium is suitable for generating pump radiation having different wavelengths. In an advantageous embodiment of the invention, the pump medium is suitable for generating pump radiation having the first pump wavelength and pump radiation having the second pump wavelength. The first and second laser media can be pumped particularly effectively using only one pump medium, the pump wavelength of which is optionally adjustable or has a correspondingly large spectral range.

[0027] In a further embodiment of the invention, the position of the first laser medium and / or the position of the second laser medium can be changed independently of the position of the pump medium. The pump medium is preferably fixed, immovable, and pumps the first and second laser medium such that the pump medium pumps the first laser medium with a suitable first pump radiation and the second laser medium with a suitable second pump radiation.

[0028] In a further embodiment of the invention, the first laser medium can be pumped with the pump radiation generated by a first pump medium, and the second laser medium can be pumped with the pump radiation generated by a second pump medium. Each laser medium can be pumped by a respective pump medium such that the first pump medium can pump the first laser medium with a suitable first pump radiation, and the second pump medium can pump the second laser medium with a suitable second pump radiation.

[0029] In a further embodiment of the invention, the position of the first laser medium of the laser resonator is coupled to the position of the first pump medium. The first pump medium is preferably arranged at a defined distance from the first laser medium and, along with the first laser medium, also changes its position during the change in the position of the first laser medium. This is particularly advantageous when the two laser media are excited with significantly different pump wavelengths.

[0030] In a further development of the invention, the position of the second laser medium of the laser resonator is coupled to the position of the second pump medium. The second pump medium is preferably arranged at a defined distance from the second laser medium and, along with the second laser medium, also changes its position when the position of the second laser medium changes. This is particularly advantageous when the two laser media are excited with significantly different pump wavelengths.

[0031] In a further embodiment of the invention, the radiation emittable by the first laser medium is offset from the radiation emittable by the second laser medium. The first laser medium and the second laser medium typically have different beam paths. The different beam paths are offset from one another. Likewise, the beam path of the first laser medium, before its position is changed, can be offset from the beam path of the second laser medium after its position is changed. Exemplary embodiments of the method according to the invention for generating different laser radiation and of the system according to the invention for generating different laser radiation are shown in simplified schematic form in the drawings and are explained in more detail in the following description.

[0032] They show:

[0033] Fig. 1 a: Device for generating different laser radiation, two different laser media

[0034] Fig. 1 b: Device for generating different laser radiation, two different laser resonators

[0035] Fig. 2 a: Device for generating different laser radiation, two different laser resonators and two different

[0036] Frequency doubler, first laser resonator in the active beam path

[0037] Fig. 2 b: Device for generating different laser radiation, two different laser resonators and two different frequency doublers, second laser resonator in the active beam path

[0038] Fig. 3 a: Device for generating different laser radiation, two different laser resonators and two different pump media, second laser resonator in the active beam path

[0039] Fig. 3 b: Device for generating different laser radiation, two different laser resonators and two different pump media, second laser resonator in the active beam path

[0040] Fig. 4 a: Device for generating different laser radiation, two different laser resonators, two different cooling devices and two different pumping media, first laser resonator in the active beam path

[0041] Fig. 4 b: Device for generating different laser radiation, two different laser resonators, two different cooling devices and two different pumping media, second laser resonator in the active beam path Fig. 5 a: Device for generating different laser radiation, two different laser resonators, one cooling device and two different pumping media, first laser resonator in the active beam path

[0042] Fig. 5 b: Device for generating different laser radiation, two different laser resonators, a cooling device and two different pump media, second laser resonator in the active beam path

[0043] Fig. 6: Device for generating different laser radiation, five different laser resonators

[0044] Fig. 7: Device for generating different laser radiation, eight different laser resonators arranged on a cylindrical positioning device

[0045] Fig. 8 a: Device for generating different laser radiation, two laser resonators with two differently arranged parallel beam paths, first position

[0046] Fig. 8 b: Device for generating different laser radiation, two laser resonators with two differently arranged parallel beam paths, second position

[0047] Fig. 9 a: Top view of a device for generating different laser radiation, nine different laser resonators arranged on a cylindrical positioning device

[0048] Fig. 9 b: Cross-sectional view of a device for generating different laser radiation, nine different laser resonators arranged on a cylindrical positioning device

[0049] All lasers shown in this and the following embodiments are solid-state lasers. The laser media 100, 110 are rod-shaped crystals. However, the laser media 100, 110 can also comprise all known laser types, such as gas lasers (including excimer lasers and metal vapor lasers), dye lasers, or free-electron lasers. The laser resonators 10, 11, 12, 13, 14, 15, 16, and 17 can each be operated in either pulsed or continuous wave mode.

[0050] In all of the exemplary embodiments shown, the laser media 100, 110 and the laser resonators 10, 11 differ in particular in the wavelength of the emittable laser radiation, with the first laser resonator 10 and the first laser medium 100 emitting laser radiation at a first wavelength, and the second laser resonator 11 and the second laser medium 110 emitting at a second wavelength. The first and second wavelengths differ from one another. In addition, the emittable laser radiations can differ from one another, for example, in their power levels, pulsed or continuous wave operation, the number and type of transverse modes, and polarization (linear, circular). The first and second laser media can also differ with regard to crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0051] Fig. 1 shows an embodiment of a device 1 for generating different laser radiation using two different laser media 100, 110 (Fig. 1 a) or two different laser resonators 10, 11 (Fig. 1 b). The basic structure of the device 1 is shown in Fig. 1 a. The device 1 has the positioning device 20, which in this embodiment is designed as a horizontally arranged platform. In this embodiment, the device 1 has two different laser media 100, 110, which are fixedly arranged parallel to one another on the positioning device 20.

[0052] At a first point in time, the first laser medium 100 is activated and emits laser radiation at a first wavelength; the second laser medium 110 is deactivated and does not emit any laser radiation. The first laser medium 100 therefore emits laser radiation that travels along the active beam path OA. At a second point in time, the second laser medium 110 is activated and emits laser radiation at a second wavelength. For this purpose, the positioning device 20 is moved horizontally by a stepper motor perpendicular to the active beam path OA. The movement of the positioning device 20 moves the first laser medium 100, which is fixedly arranged thereon, out of the active beam path OA, and the second laser medium 110, which is also fixedly arranged on the positioning device 20, is positioned in the active beam path OA. The first laser medium 100 is optionally deactivated.

[0053] Fig. 1 b shows the structure of the device 1, wherein the device 1 comprises two different laser resonators 10, 11 with different laser media 100, 110. The first laser resonator 10 comprises the first laser medium 100 with the two confocal resonator mirrors 101, 10T, wherein one resonator mirror 101 is partially transparent for coupling out the laser beam.

[0054] The second laser resonator 11 has the second laser medium 110 and the two confocal resonator mirrors 111, 11T, wherein one resonator mirror 111 is also partially transparent.

[0055] To generate different laser radiation, analogous to the previous embodiment (see Fig. 1 a), the first laser resonator 10 is activated, which emits laser radiation at a first wavelength, while the second laser resonator 11 is not activated. The first laser resonator 10 therefore emits laser radiation that travels along the active beam path OA. At a second point in time, the second laser resonator 11 is activated and emits laser radiation at a second, different wavelength. The positioning device 20 is moved by a stepper motor in a horizontal direction, also perpendicular to the active beam path OA. By moving the positioning device 20, the first laser resonator 10, which is fixedly arranged thereon, is moved out of the active beam path OA and, at the same time, the second laser resonator 11, which is also fixedly arranged on the positioning device 20, is positioned in the active beam path OA. Fig.Figure 2 shows an embodiment of the device 1 according to the invention with two laser resonators 10, 11. The first laser resonator 10 has the first laser medium 100 with the two confocal resonator mirrors 101, 10T, one resonator mirror 101 being partially transparent for coupling out the laser beam. A nonlinear medium (frequency-converting element) 102 is arranged in the beam path OA behind the resonator mirror 101 outside the laser resonator 10 (Figure 2a), with which the frequency of the laser radiation emitted by the first laser resonator 10 is doubled.

[0056] The second laser resonator 11 comprises the second laser medium 110 and the two confocal resonator mirrors 111, 11T, one of which is also partially transparent. Behind the resonator mirror 111 is the nonlinear medium 112 (frequency-converting element), which doubles the frequency of the laser radiation emitted by the second laser resonator 11.

[0057] To generate different laser radiation, the first laser resonator 10 is activated, which emits laser radiation at a first wavelength. The first laser resonator 10 therefore emits laser radiation that travels along the active beam path OA and undergoes frequency doubling by the non-linear medium. At a second point in time, the second laser resonator 11 is activated and emits laser radiation at a second, different wavelength, which is halved by the non-linear medium 112 (frequency-converting element). The positioning device 20 is moved horizontally, also perpendicular to the active beam path OA, by a stepper motor. The movement of the positioning device 20 moves the first laser resonator 10, which is fixedly arranged thereon, out of the active beam path OA, and simultaneously positions the second laser resonator 11, which is also fixedly arranged on the positioning device 20, into the active beam path OA (Fig.2 b).

[0058] Fig. 3 shows an embodiment of the device 1 with two laser resonators 10, 11 arranged at a distance from one another on a positioning device 20, in which each laser medium 100, 110 is pumped by a respective pump medium 103, 113. The pump media 103, 113 in this and all other embodiments are flash lamps, but lasers, in particular diode lasers, or gas discharge tubes are also possible.

[0059] The first laser medium 100 generates laser radiation with a first wavelength and is pumped by a first pump medium 103 with pump radiation with a first pump wavelength. The second laser medium 110 is pumped by the second pump medium 113 with pump radiation with a second pump wavelength that differs from the first pump wavelength of the first pump medium 103 and generates a second laser radiation with a second wavelength that differs from the first wavelength generated by the first laser medium 100. The first and second laser media 110, 110 can also differ with regard to crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0060] To generate different laser radiation, the first laser resonator 10 is activated at a first point in time, the first laser medium 100 is pumped by the first pump medium 103, and the first laser resonator 10 emits laser radiation onto the active beam path OA at a first wavelength (Fig. 3a). The positioning device 20 is moved horizontally perpendicular to the active beam path OA by a stepper motor. By moving the positioning device 20, the first laser resonator 10 and the first pump medium 103, which are fixedly arranged thereon, are moved out of the active beam path OA, and at the same time the second laser resonator 11 and the second pump medium 113, which are also fixedly arranged on the positioning device 20, are positioned into the active beam path OA. At a second point in time, the second laser resonator 11 is activated.The second laser medium 110 is pumped by the second pump medium 113, and the second laser resonator 11 emits laser radiation along the active beam path OA at a second wavelength (Fig. 3 b). In an alternative embodiment, the device 1 has only one pump medium 103, with both laser media 100, 110 being pumped by this single pump medium 103. The pump medium 103 is therefore suitable for emitting pump radiation at a first pump wavelength for pumping the first laser medium 100 and a second pump wavelength for pumping the second laser medium 110.

[0061] Fig. 4 shows a further embodiment of the device 1 with two laser resonators 10, 11 arranged at a distance from one another on the positioning device 20, with two pumping media 103, 113 and two cooling devices 104, 114. The first laser resonator 10 is arranged with the first pumping medium 103 and the first cooling device 104 as a structural unit fixed on the positioning device 20; in the same way, the second laser resonator 11 with the first pumping medium 113 and the second cooling device 114 is arranged as a structural unit fixed on the positioning device 20.

[0062] To generate different laser radiation, the first laser resonator 10 is activated at a first time, the first laser medium 100 is pumped by the first pump medium 103, the first laser resonator 10 emits laser radiation on the active beam path OA at a first wavelength (Fig. 4a) and is cooled by the first cooling device 104. The positioning device 20 is moved by a stepper motor perpendicular to the active beam path OA in the horizontal direction. By moving the positioning device 20, the first laser resonator 10 and the first pump medium 103, which are fixedly arranged thereon, are moved out of the active beam path OA and, at the same time, the second laser resonator 11 and the second pump medium 113, which are also fixedly arranged on the positioning device 20, are positioned in the active beam path OA.At a second point in time, the second laser resonator 11 is activated, the second laser medium 110 is pumped by the second pump medium 113, and the second laser resonator 11, cooled by the second cooling device 114, emits laser radiation along the active beam path OA at a second wavelength (Fig. 4b). In a variant of the above embodiment (see Fig. 4), shown in Fig. 5, the device has only one cooling device 124, which cools two laser resonators 10, 11. The first laser resonator 10 is fixedly arranged on the positioning device 20 with the first pump medium 103; in the same way, the second laser resonator 11 with the first pump medium 113 is fixedly arranged as a structural unit on the positioning device 20. The position of both laser resonators 10, 11 can therefore be changed by the positioning device 20.In contrast, the cooling device 124 is not arranged on the positioning device 20 and therefore cannot be changed in its position by the positioning device 20.

[0063] To generate different laser radiation, the first laser resonator 10 is activated at a first time, the first laser medium 100 is pumped by the first pump medium 103, the first laser resonator 10 emits laser radiation on the active beam path OA at a first wavelength (Fig. 5a) and is cooled by the cooling device 124. The positioning device 20 is moved by a stepper motor perpendicular to the active beam path OA in the horizontal direction. By moving the positioning device 20, the first laser resonator 10 and the first pump medium 103, which are fixedly arranged thereon, are moved out of the active beam path OA and, at the same time, the second laser resonator 11 and the second pump medium 113, which are also fixedly arranged on the positioning device 20, are positioned in the active beam path OA.At a second time, the second laser resonator 11 is activated, the second laser medium 110 is pumped by the second pump medium 113 and the second laser resonator 11, cooled by the cooling device 124, emits laser radiation on the active beam path OA with a second wavelength (Fig. 5 b).

[0064] The first and second laser media 100, 110 may also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency. The first and second laser media 100, 110 may also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0065] Fig. 6 shows a further embodiment of the device 1 according to the invention with five laser media 100, 110, 120, 130, 140, which are arranged parallel to one another on the positioning device 20. According to the invention, any number of laser media can be arranged on the positioning device 20, depending on the dimensions of the positioning device 20 and the laser media to be arranged thereon.

[0066] The laser media 100, 110, 120, 130, 140 each emit laser radiation at a different wavelength. To generate different laser radiation, the second laser medium 110 is activated, which emits laser radiation at a second wavelength; all other laser media 100, 120, 130, 140 are not activated. The second laser medium 110 therefore emits laser radiation at the second wavelength, which runs along the active beam path OA. At further times, the positioning device 20 is moved horizontally perpendicular to the active beam path OA such that a further laser medium 100, 120, 130, 140 is positioned in the active beam path OA and emits laser radiation at a wavelength correspondingly different from the second wavelength. All other laser resonators not positioned in the active beam path OA are deactivated.The first and second laser media 100, 110 may also differ in terms of crystal type, crystal doping, and other crystal properties, such as fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0067] Fig. 7 shows an advantageous variant of the device 1 according to the invention with eight laser media 100, 110, 120, 130, 140, 150, 160, 170, which are arranged coaxially on a positioning device 20 and whose crystals have different cross-sections. All laser media 100, 110, 120, 130, 140, 150, 160, 170 also emit laser radiation with mutually different wavelengths. The first and second laser media 100, 110 can also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0068] In contrast to all embodiments shown so far, no translational movement of the positioning device 20 takes place to generate different laser radiation, but rather a rotational movement about the central axis of the positioning device 20. Furthermore, a cooling device 104 is arranged around the laser media 10, 11, 12, 13, 14, 15, 16, 17 or their crystals.

[0069] To generate different laser radiation, the first laser medium 100 is activated, which emits laser radiation at a first wavelength; all other laser media 110, 120, 130, 140, 150, 160, 170 are deactivated. The first laser medium 100 therefore emits laser radiation at the first wavelength, which runs along the active beam path OA. At subsequent times, the positioning device 20 is rotated about its central axis such that a further laser medium 110, 120, 130, 140, 150, 160, 170 is positioned in the active beam path OA and emits laser radiation at a wavelength correspondingly different from the first wavelength. All other laser media 100, 110, 120, 130, 140, 150, 160, 170 that are not positioned in the active beam path OA are deactivated.

[0070] Fig. 8 shows a further embodiment of the device 1 according to the invention with two laser resonators 10, 11, which are arranged parallel and next to one another on the positioning device 20. The positioning device 20 is movably connected to the first cooling device 104 via a heat conductor 30, wherein the cooling device 104 is arranged on two opposite sides of the positioning device 20. The heat conductor can also be designed as a plain bearing or as a heat-conducting medium, such as a thermal paste.

[0071] The two laser resonators 10, 11 each emit laser radiation at different wavelengths. To generate different laser radiation, the first laser resonator 10 is activated (Fig. 8 a), which emits laser radiation at a first wavelength, while the second laser resonator 11 is not activated. The first laser resonator 10 therefore emits laser radiation at the first wavelength, which runs along the active beam path OA. At a further point in time, the positioning device 20 is moved horizontally perpendicular to the active beam path OA such that the second laser resonator 11 is positioned in the active beam path OA (Fig. 8 b) and emits laser radiation at a wavelength correspondingly different from the first wavelength. The first laser resonator 10 is not activated. During the movement of the positioning device 20 relative to the cooling device 104, the positioning device 20 slides in the thermal paste 30.In an alternative embodiment, two different resonators are installed, which are made of different crystal materials and yet produce the same wavelength.

[0072] Fig. 9 shows a further advantageous variant of the device 1 according to the invention with nine laser media 100, 110, 120, 130, 140, 150, 160, 170, 180, wherein the laser media 170, 180 are not shown. The laser media 100, 110, 120, 130, 140, 150, 160, 170, 180 are arranged in groups of three on the positioning device 20, wherein the first group of three comprises the laser media 100, 110, 120, the second group of three comprises the laser media 130, 140, 150, and the third group of three comprises the laser media 160, 170, 180. Within the first group of three, the laser media 100, 110, 120 are arranged parallel to one another, within the second group of three the laser media 130, 140, 150 and within the third group of three the laser media 160, 170, 180. In further embodiments, arrangements with more than 9 laser media are also possible.All laser media 100, 110, 120, 130, 140, 150, 160, 170, 180 also emit laser radiation with different wavelengths. In contrast to the previously shown embodiments, a translational movement of the positioning device 20 and / or a rotational movement around the central axis of the positioning device 20 is performed to generate different laser radiation.

[0073] To generate different laser radiation, the second laser medium 110 is activated (Fig. 9 a), which emits laser radiation at a second wavelength; all other laser media 100, 120, 130, 140, 150, 160, 170, 180 are not activated. The second laser medium 110 therefore emits laser radiation at the second wavelength, which runs along the active beam path OA. At further times, the positioning device 20 is translated in its longitudinal direction and / or rotated about its central axis such that one of the other laser media 100, 120, 130, 140, 150, 160, 170, 180 is positioned in the active beam path OA and emits laser radiation at a wavelength correspondingly different from the second wavelength. All other laser media that are not positioned in the active beam path OA are deactivated.The different laser media 100, 110, 120, 130, 140, 150, 160, 170, 180 can also differ in terms of crystal type, crystal doping and other crystal properties, such as the fluorescence lifetime, which affects the energy or pulse peak power at a given pulse repetition frequency.

[0074] 10a and 10b each show different views of a device 1 for generating different laser radiation. The device 1 for generating different laser radiation has a laser resonator 10, a first laser medium 100 arranged in the beam path OA of the laser resonator 10, a second laser medium 110 and a third laser medium 120, which can also be arranged in the beam path of the laser resonator, and a positioning device 20 by which the laser media 100, 110, 120 can be positioned in the beam path. The laser media differ in their shape and in that the individual laser media 100, 110, 120 can emit laser radiation with different wavelengths. The laser resonator further has two resonator mirrors 101, 10T and a Q-switch 40.The pump radiation 123 is coupled in through one of the resonator mirrors 101 and pumps the laser medium 100 located in the beam path OA. The laser media 100, 110, 120 are each moved into and out of the beam path by a positioning device 20. The positioning device 20 has a housing 21, a motor 22, and a support element 23 driven by the motor 22, on which the laser media 100, 110, 120 are mounted. The motor 22 causes the support element 23 to rotate with a rotation axis perpendicular to the beam path OA, thus moving the individual laser media. The laser media are arranged on the positioning arrangement such that they do not touch the rotation axis. The different laser media 100, 110, 120 can also be differentiated with regard to crystal type, crystal doping and other crystal properties, such as the fluorescence lifetime, which affect the energy or wavelength.The effect of peak pulse power at a given pulse repetition rate may vary.

[0075] Fig. 11a shows a further embodiment of a positioning device 20 and Fig. 11b shows a further embodiment of a carrier element 23. The positioning device 20 has a housing 21, a motor 22 and a carrier element 23 driven by the motor 22, on which the various laser media 100, 110, 120, 130 are mounted. The laser media 100, 110, 120, 130 are arranged on several different circular paths. A change of the laser medium 100 in the beam path occurs by rotation and / or translation of the carrier element 23. The two laser media 100, 110 arranged on the first circular path can be changed by a rotational movement of the carrier element 23 about a rotation axis perpendicular to the beam path OA. A change between the circular paths can be made by translating the carrier element 23 in a direction perpendicular to the beam path OA.In this way, the other two laser media 120, 130 can also be positioned in the beam path OA. The different laser media 100, 110, 120, 130 can also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency. Figs. 12a and 12b each show a device 1 for generating different laser radiation, comprising a laser resonator 10, a first laser medium 100 arranged in the beam path OA of the laser resonator 10, a second laser medium 110, and a third laser medium, which can also be arranged in the beam path of the laser resonator, and a positioning device 20 (not shown), by means of which the laser media 100, 110, 120 can be positioned in the beam path.The laser media differ in their shape and in that the individual laser media 100, 110, 120 can emit laser radiation with different wavelengths. The laser resonator further comprises two resonator mirrors 101, 101' and a Q-switch 40. The pump radiation 123 is coupled in through one of the resonator mirrors 101 and pumps the laser medium 100 located in the beam path OA. The laser media 100, 110, 120 are moved into and out of the beam path by a rotational movement about a rotation axis perpendicular to the beam path OA. The laser media 100, 110, 120 are mounted on a carrier element 23. The laser media are arranged on the positioning arrangement in such a way that they do not touch the rotation axis. In addition, a non-linear medium 102 is arranged on the carrier element 23, which can also be moved in and out of the beam path OA.The nonlinear medium is arranged such that it moves together with the first laser medium 100 into the beam path OA and multiplies the frequency of the laser radiation generated in the laser resonator by the first laser medium 100. Optionally, instead of the nonlinear medium shown, several nonlinear media can be arranged, which are then all moved together with the laser medium. The carrier element 23 performs a rotational movement with a rotation axis perpendicular to the beam path OA and thus moves the individual laser media 100, 110, 120 and the nonlinear medium 102. The different laser media 100, 110, 120 can also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.Instead of the nonlinear medium 102, another crystal can simply be used, which does not serve to multiply the laser radiation, but rather serves other functions, such as extending the pulse repetition rate and / or energy. This can also involve multiple and / or different crystals, such as an Nd:YVO4 crystal and an Nd:YAG crystal.

[0076] Fig. 13 shows a device 1 for generating different laser radiation with a laser resonator 10, a first laser medium 100 arranged in the beam path OA of the laser resonator 10, further laser media 110, 120, 130, 140, 150, 160, 170, which can also be arranged in the beam path of the laser resonator, and a positioning device 20, by means of which the laser media 100, 110, 120, 130, 140, 150, 160, 170 can be positioned in the beam path. The laser media 100, 110, 120, 130, 140, 150, 160, 170 differ in their shape and in that the individual laser media 100, 110, 120, 130, 140, 150, 160, 170 can emit laser radiation with different wavelengths. The laser resonator further comprises two resonator mirrors 101, 101' and a Q-switch 40. The pump radiation 123 is coupled in through one of the resonator mirrors 101 and pumps the laser medium 100 located in the beam path OA.The laser media 100, 110, 120, 130, 140, 150, 160, 170 are each moved into and out of the beam path by a positioning device 20. The positioning device 20 comprises a housing 21, a motor 22, and a support element 23 driven by the motor 22, on which the laser media 100, 110, 120, 130, 140, 150, 160, 170 are mounted. The motor 22 causes the carrier element 23 to rotate with a rotation axis parallel to the beam path OA, thus moving the individual laser media 100, 110, 120, 130, 140, 150, 160, 170. The different laser media 100, 110, 120, 130, 140, 150, 160, 170 can also differ in terms of crystal type, crystal doping, and other crystal properties, such as the fluorescence lifetime, which affects the energy or peak pulse power at a given pulse repetition frequency.

[0077] Figure 14 shows the positioning device 22 according to the invention. The positioning device 22 is linearly displaceable in two directions. It has a total of six laser media 100, 110, 120, 130, 140, 150, which are arranged in a 3x2 matrix. Due to the displaceability in two directions, each of the laser media 100, 110, 120, 130, 140, 150 can be positioned in the active beam OA. The positioning device 22 itself also serves as a cooling element 104, since it is suitable for cooling the laser media

[0078] 100, 110, 120, 130, 140, 150 to dissipate the heat generated through your body.

[0079] Figures 15a to 15c show a spherical positioning device 22. Figure 15a shows a plurality of beam inlets or outlets 105 arranged on the spherical surface, with each beam inlet 105 being opposite a beam outlet 105. The beam is guided OA through the positioning device 22 through the center of the spherical positioning device 22. Figure 15b shows the arrangement of the laser media 130, 130', 140, 140', 150, 150', 160, 160' in the spherical positioning device 22 in a sectional view along the section axis AA'. Two laser media 130, 130', 140, 140', 150, 150', 160, 160' are always arranged along the possible optical axes OA. By rotating the spherical positioning device 22, the laser media 130, 130', 140, 140', 150, 150', 160, 160' can be positioned in pairs in the beam path OA.By rotating the spherical positioning device 22, the beam inlets and outlets 105 are moved together with the laser media 130, 130', 140, 140', 150, 150', 160, 160' arranged in the spherical positioning device. Fig. 15c shows a sectional view along the section axis B - B' with further arrangement possibilities of laser media 100, 100', 100", 110, 110', 120, in the spherical positioning device 22. In one possible arrangement of the beam path OA through the spherical positioning device 22, the laser beam OA passes through only one laser medium 120. In a second possible positioning of the spherical positioning device 22 relative to the beam path, the laser beam OA passes through two laser media 110, 110', while in a third possible positioning of the spherical positioning device, three laser media 100, 100', 100" pass through.

[0080] LIST OF REFERENCE SYMBOLS

[0081] Device for generating different laser radiation

[0082] First laser resonator

[0083] Second laser resonator, 100', 100“ First laser medium, 110' Second laser medium, 120' Third laser medium, 130' Fourth laser medium, 140' Fifth laser medium, 150' Sixth laser medium, 160' Seventh laser medium

[0084] Eighth laser medium

[0085] Ninth laser medium

[0086] Positioning device

[0087] Motor

[0088] Housing

[0089] Support element

[0090] Heat conductor

[0091] Q-switch, 111 Resonator mirror with window for coupling out the laser beam, 111' Resonator mirror, 112 Non-linear medium (frequency converting element), 113 Pump device / pump diode

[0092] Pump radiation 104, 114, 124 Cooling device

[0093] 105 Beam input, beam output

[0094] OA Active beam path

Claims

PATENT CLAIMS 1. Method for generating different laser radiation in a laser resonator with the method steps a) generating a first laser radiation with a first laser medium (100), b) changing the position of the first laser medium (100), c) changing the position of a second laser medium (110), d) generating a second laser radiation with the second laser medium (110), characterized in that the first and the second laser medium (100,110) differ in a physical property.

2. A method for generating different laser radiation in a laser resonator according to claim 1, characterized in that the physical property is a laser-optical property.

3. Method for generating different laser radiation in a laser resonator according to claim 1 or 2, characterized in that the first and the second laser medium (100, 110) differ in their crystal type, crystal doping and further crystal properties, such as the thermal properties and / or the fluorescence lifetime, which affects the energy or pulse peak power at a given pulse repetition frequency, and / or the radiation emitted by the laser media (100, 110) with regard to the power, the operation in pulse or continuous wave, the number and type of transverse modes, the polarization (linear, circular), the absorption linewidth, emission linewidth and / or wavelength.

4. Method for generating different laser radiation in a Laser resonator according to one or more of the preceding claims, characterized in that the first laser medium (100) is arranged in a first laser resonator (10) and the second laser medium (110) is arranged in a second laser resonator (11), wherein upon changing the position of the first Laser medium (100) the position of the first laser resonator (10) is changed and when the position of the second laser medium (110) is changed the position of the second laser resonator (11) is changed.

5. Method for generating different laser radiation in a laser resonator according to claim 4, characterized in that by changing the position of the first laser medium (100) the first laser medium (100) is removed from the active beam path (OA).

6. Method for generating different laser radiation in a laser resonator according to one or more of the preceding claims, characterized in that by changing the position of the second laser medium (110), the second laser medium (110) is positioned in the active beam path (OA).

7. Method for generating different laser radiation in a laser resonator according to one or more of the preceding claims, characterized in that the first laser medium (100) is pumped with pump radiation having a first pump wavelength and the second laser medium (110) is pumped with pump radiation having a second pump wavelength, wherein the first pump wavelength is different from the second pump wavelength.

8. A method for generating different laser radiation in a laser resonator according to claim 7, characterized in that the pump radiation with the first pump wavelength and the pump radiation with the second pump wavelength are generated by a pump medium (103, 113), wherein the pump medium (103, 113) is suitable for generating pump radiation with different wavelengths.

9. A method for generating different laser radiation in a laser resonator according to claim 8, characterized in that the pump medium (103, 113) generates pump radiation with the first pump wavelength and pump radiation with the second pump wavelength.

10. A method for generating different laser radiation in a laser resonator according to claim 8 or 9, characterized in that during the change in the position of the first laser medium (100) and / or during the change in the position of the second laser medium (110), the position of the pump medium (103, 113) remains unchanged.

11. A method for generating different laser radiation in a laser resonator according to claim 10, characterized in that the first laser medium (100) is pumped with the pump radiation generated by a first pump medium (103) and the second laser medium (110) is pumped with the pump radiation generated by a second pump medium (113).

12. A method for generating different laser radiation in a laser resonator according to claim 11, characterized in that the position of the first pump medium (103) is changed by changing the position of the first laser medium (100).

13. A method for generating different laser radiation in a laser resonator according to claim 11 or 12, characterized in that the position of the second pump medium (113) is changed by changing the position of the second laser medium (110).

14. A method for generating different laser radiation in a laser resonator according to one or more of the preceding claims, characterized in that the radiation emitted by the first laser medium (100) is offset from the radiation emitted by the second laser medium (110).

15. Device (1) for generating different laser radiation with • a laser resonator, • a first laser medium (100) that can be arranged in the beam path of the laser resonator, • a second laser medium (110) which can be arranged in the beam path of the laser resonator, • a positioning device (20) which is suitable for positioning the first (100) and / or second laser medium (110) in the beam path, wherein the first and second laser medium (100,110) differ in a physical property.

16. Device (1) for generating different laser radiation according to claim 15, characterized in that the positioning device is suitable and intended to dissipate the heat generated in the positioning unit.

17. Device (1) for generating different laser radiation according to claim 15 or 16, characterized in that the physical property is a laser-optical property.

18. Device (1) for generating different laser radiation according to claim 17, characterized in that the first and the second laser medium (100, 110) differ in their crystal type, crystal doping and other crystal properties, such as the thermal properties and / or the fluorescence lifetime, which affects the energy or pulse peak power at a given pulse repetition frequency, and / or the radiation emitted by the laser media (100, 110) with regard to the power, the operation in pulse or continuous wave, the number and type of transverse modes, the polarization (linear, circular), the absorption linewidth, the emission linewidth and / or the wavelength.

19. Device (1) for generating different laser radiation according to one or more of claims 15 to 18, characterized in that the first laser medium (100) can be positioned in the active beam path (OA) and outside the active beam path (OA) of the laser resonator (10).

20. Device (1) for generating different laser radiation according to one or more of claims 15 to 19, characterized in that the second laser medium (110) can be positioned in the active beam path (OA) and outside the active beam path (OA) of the laser resonator (10).

21. Device (1) for generating different laser radiation according to one or more of claims 15 to 20, characterized in that the first laser medium (100) can be pumped with a pump radiation having a first pump wavelength and the second laser medium (110) can be pumped with a pump radiation having a second pump wavelength, wherein the first pump wavelength is different from the second pump wavelength.

22. Device (1) for generating different laser radiation according to claim 21, characterized in that the device (1) has a pump medium (103), wherein the pump radiation with the first pump wavelength and the pump radiation with the second pump wavelength can be generated by this pump medium (103), wherein the pump medium (103) is suitable for generating pump radiation with different wavelengths.

23. Device (1) for generating different laser radiation according to claim 22, characterized in that the pump medium (103, 113) is suitable for generating pump radiation with the first pump wavelength and pump radiation with the second pump wavelength.

24. Device (1) for generating different laser radiation according to claim 22 or 23, characterized in that the position of the first laser medium (100) and / or the position of the second laser medium (110) can be changed independently of the position of the pump medium (103, 113).

25. Device (1) for generating different laser radiation according to claim 24, characterized in that the first laser medium (100) can be pumped with the pump radiation generated by a first pump medium (103) and the second laser medium (110) can be pumped with the pump radiation generated by a second pump medium (113).

26. Device (1) for generating different laser radiation according to claim 25, characterized in that the position of the first laser medium (100) is coupled to the position of the first pump medium (103).

27. Device (1) for generating different laser radiation according to claim 25 or 26, characterized in that the position of the second laser medium (110) is coupled to the position of the second pump medium (113).

28. Device (1) for generating different laser radiation according to one or more of claims 15 to 27, characterized in that the radiation emittable by the first laser medium (100) is offset from the radiation emittable by the second laser medium (110).

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