Optical apparatus

Abstract

The invention relates to an optical device (10) comprising a laser-active solid body (12), a pump radiation source (14) and a reflector (16). The laser-active solid (12) is designed to amplify and / or generate a laser beam (46) and is in the form of a slab. The pump radiation source (14) is designed to generate a pump beam (20) which propagates in a propagation direction (24) and passes through the laser-active solid body (12) for the purpose of optical pumping. The reflector (16) is arranged behind the laser-active solid body (12) in the propagation direction (24) of the pump beam (20) and is configured to reflect the pump beam (20) transmitted through the laser-active solid body (12) back onto the laser-active solid body (12). For the purpose of optical pumping, the pump beam (20) reflected by the reflector (16) passes through the laser-active solid (12).

Description

Technical Field

[0001] This invention relates to optical devices. Background Technology

[0002] Optical equipment is frequently used for optical pumping of slab lasers. Slab lasers typically consist of laser-active solids with a slab-like structure, especially in the form of laser-active crystals with a slab-like structure.

[0003] The term "slab-like structure" can be understood as the laser-active solid having a plate-like (plattenförmig) structure. In other words, the laser-active solid can be constructed as a cuboid, wherein the height of the laser-active solid is less than its width and length. This shape allows for better cooling of the laser-active solid, especially improving the dissipation of heat generated by amplifying and / or generating the laser beam.

[0004] For optical pumping purposes, the pump beam is typically coupled into the laser-active solid at one end face using optical equipment. After coupling into the laser-active solid, the pump beam passes through the laser-active solid and exits at the end face opposite to the aforementioned end face. To amplify an existing laser beam, optical equipment can be used to couple the existing laser beam into the laser-active solid. After coupling into the laser-active solid, the laser beam passes through the laser-active solid and is amplified within the laser-active solid in the overlapping region of the laser beam and the pump beam.

[0005] EP1181754A1 discloses an optical amplifier device having a shaped amplifying medium with a slatted structure and two highly reflective mirrors arranged between the two highly reflective mirrors.

[0006] The object of this invention is to provide an optical device that enables the amplification and / or generation of laser beams with high efficiency. Summary of the Invention

[0007] The present invention achieves these objectives by providing an optical device having the features of claim 1. Advantageous configurations and further extensions of the invention are derived according to the dependent claims.

[0008] The optical device according to the present invention includes a laser-active solid, a pump radiation source, and a reflector. The laser-active solid is configured to amplify and / or generate a laser beam. The laser-active solid has a slab-like structure. The pump radiation source is configured to generate a pump beam that propagates along a propagation direction and passes through the laser-active solid for optical pumping purposes. The reflector is arranged behind the laser-active solid along the propagation direction of the pump beam. The reflector is configured to reflect the pump beam transmitted through the laser-active solid back onto the laser-active solid. For optical pumping purposes, the pump beam reflected by the reflector passes through the laser-active solid.

[0009] Advantageously, the optical device enables the efficient amplification and / or generation of a laser beam by reflecting the unabsorbed portion of the pump beam transmitted through the laser-active solid back onto the laser-active solid, thereby optically pumping the laser-active solid. This allows the use of pump radiation that is not absorbed during the first transmission of the pump beam through the laser-active solid. Advantageously, the optical device enables the power of the pump beam to be uniformly distributed across the laser-active solid, resulting in uniform heating of the laser-active solid and thus minimizing the impact on the beam quality of the laser beam as it passes through the laser-active solid.

[0010] Optical pumping can be understood as the effect of population inversion caused by photoexcitation, particularly due to electron-photon interactions. Population inversion can occur when the energy levels of a particle or molecule are not occupied by electrons in the manner expected at a given temperature without photoexcitation. In other words, optical pumping can be the process of raising electrons in an atom or molecule from a lower energy level to a higher energy level using a pump beam.

[0011] When a pump beam passes through a laser-active solid, it can optically pump the solid. Optical pumping involves partial absorption of the pump beam by the laser-active solid, thereby inducing population inversion within the solid. Optical pumping reduces the power of the pump beam. The transmitted pump beam can be the remaining residual beam of the pump beam generated by the pump radiation source. The transmitted pump beam can be described as the pump beam that was not absorbed by the laser-active solid. The transmitted pump beam can be the portion of the pump beam generated by the pump radiation source that did not optically pump the laser-active solid after passing through it.

[0012] The pump radiation source can be a diode laser, and in particular, it can have a laser diode.

[0013] The wavelengths of the pump beam and the laser beam can be different. The wavelength of the pump beam can be matched with the laser-active solid, especially with the material of the laser-active solid, so that the laser-active solid can be optically pumped by the pump beam. The wavelength of the laser beam can be matched with the laser-active solid, so that the laser beam can be amplified by the laser-active solid through stimulated emission.

[0014] The wavelength of the pump beam can be from 850 nm to 990 nm, especially from 880 nm to 890 nm, and preferably from 885 nm. The wavelength of the laser beam can be from 1000 nm to 1180 nm, especially from 1060 nm to 1065 nm. The abbreviation nm stands for nanometer.

[0015] Laser beam amplification or generation using a laser-active solid can be achieved through stimulated emission. The laser beam and pump beam can overlap (überlappen), or more specifically, superimpose (überlagern), within the laser-active solid. In particular, the laser beam and pump beam can be superimposed both temporally and spatially within the laser-active solid. This overlap allows both beams to propagate within the solid, thereby amplifying the laser beam. The propagation directions of the laser beam and the pump beam can be different.

[0016] The reflector can be a retroreflector or a mirror, especially a Bragg mirror. The reflector can have a coating that is highly reflective to the pump beam, especially a dielectric coating. The reflector can be disposed on the end surface or end face of the laser-active solid.

[0017] The reflector can be configured to reflect the transmitted pump beam such that the pump beam at least partially overlaps with itself within the laser-active solid before and after reflection by means of the reflector, especially superimposes.

[0018] Laser-active solids can be, in particular, crystalline, especially crystalline structures. Laser-active solids can also be called laser crystals.

[0019] In another extension of the optical device, the reflector is configured to reflect the pump beam transmitted through the laser-active solid back with spatial and / or angular offset. The spatial offset is configured such that the pump beam reflected by the reflector enters the pump source at less than 5% of its power, particularly 3% or 2%. Advantageously, this avoids damage to the pump source from the reflected pump beam and excessive heating of the pump source. In particular, 5% of the power of the reflected pump beam, particularly 3% or 2%, can irradiate the pump source without affecting and / or damaging it.

[0020] In another extension of the optical device, the reflector is configured such that the angle of incidence of the pump beam transmitted through the laser-active solid relative to the reflector is not equal to 0°. Alternatively, the reflector is configured such that the angle of exit of the pump beam reflected by the reflector is not equal to 0°. The angle of incidence and the angle of exit can be the same.

[0021] In another extended embodiment, the optical device includes a polarizer. The polarizer is positioned between the pump radiation source and the laser-active solid. The polarizer is configured to filter the pump beam according to its polarization, so that the pump beam is linearly polarized after the polarizer. The optical device has... Wave plate. The waveplate is positioned between the polarizer and the reflector. The waveplate is configured to convert the linear polarization of the pump beam to the circular polarization of the pump beam, and to convert the circular polarization of the pump beam to the linear polarization. The polarizer can be configured to deflect the pump beam according to its polarization.

[0022] Wave plates can be made of birefringent materials. Waveplates can have fast and slow axes, where, The waveplate delays the phase of the beam component polarized parallel to the slow axis by one-quarter of the phase of the beam component polarized parallel to the fast axis. This indicates the wavelength of the pump beam.

[0023] The polarizer can be configured to filter the pump beam using dichroism, reflection, birefringence, scattering, and / or diffraction based on the polarization of the pump beam. The polarizer can have, in particular, a film polarizer, a thin-layer polarizer, a wire grid polarizer, a crystal polarizer, a polarization beam splitter, or a Brewster window.

[0024] The pump beam generated by the pump radiation source can be linearly polarized. The degree of polarization of a linearly polarized pump beam can be greater than 85%, especially 90% or 95%.

[0025] The polarizer can be arranged such that the pump beam passes through the laser-active solid after passing through the polarizer.

[0026] In other expansion schemes for optical equipment, The waveplates are arranged such that the pump beam passes through before being reflected by the reflector. The waveplate, and the pump beam, after being reflected by the reflector, pass through... Waveplate. Advantageously, this can be achieved such that after being reflected by the reflector and passing through... The polarization of the pump beam after the waveplate is relative to that after passing through The polarization of the pump beam before the waveplate was rotated by 90°.

[0027] In other expansion schemes for optical equipment, The waveplate is configured to change the polarization of the pump beam, so that when passing through... The linear polarization of the pump beam before the waveplate and the pump beam reflected by the reflector as it passes through... The linear polarizations behind the waveplate are orthogonal to each other.

[0028] In another extension of the optical device, the polarizer is configured to filter the pump beam reflected by the reflector according to its polarization, such that the pump beam reflected by the reflector enters the pump radiation source at less than 5% of its power, particularly 3% or 2%. Advantageously, this avoids damage to the pump radiation source by the reflected pump beam. In particular, 5% of the power of the reflected pump beam, particularly 3% or 2%, can irradiate the pump radiation source without affecting and / or damaging it.

[0029] In another extension of the optical device, the reflector is a wavelength-selective element configured to reflect the pump beam wavelength more strongly than the laser beam wavelength. The reflectivity of the reflector to the pump beam wavelength can be at least 95%, particularly 98%, 99%, 99.9%, or 99.99%. The reflectivity of the reflector to the laser beam wavelength can be at most 5%, particularly 3%, 1%, 0.5%, 0.3%, or 0.1%.

[0030] In another extended scheme, the reflector is wavelength-selective, such that it essentially reflects wavelengths within the absorption band of the laser-active solid. In particular, the reflected pump radiation, guided back through the laser-active solid, can be largely absorbed or absorbed by the solid after two passes. This wavelength selectivity also prevents the emission of the pump radiation source from being undesirably deflected to wavelengths less readily absorbed by the solid due to feedback.

[0031] In another extension of the optical device, the laser-active solid is formed of a material doped with ytterbium or neodymium ions. For example, the material is or includes the following: Yb:YAG, Nd:YAG, Yb:LuAG, Yb:CaF2, Yb:CALGO, Yb:Lu2O3, Yb:Sc2O3, Yb:GGG, Yb:YLF, Yb:S-FAP, Nd:YVO4, Nd:GdVO4, Yb:KGW, or Yb:KYW. Advantageously, these materials are particularly suitable for the efficient amplification and / or generation of laser beams, and can exhibit low heat generation during amplification and / or generation.

[0032] In another extended embodiment, the optical device includes a cooling device for cooling the laser-active solid. The cooling device can be described as a heat sink. The laser-active solid can be in contact with the cooling device. The cooling device can have a first cooling plate and a second cooling plate, wherein the first cooling plate is arranged on a first longitudinal side of the laser-active solid, and wherein the second cooling plate is arranged on a second longitudinal side opposite to the first longitudinal side. The cooling device can be a water-cooled device.

[0033] In another extension of the optical device, the reflector has a curved surface. The reflector is configured such that the curvature of the curved surface is equal to the curvature in front of the pump beam. Advantageously, this preserves the caustic lines of the pump beam after reflection by the reflector, thereby improving the overlap between the pump beam and the laser beam, and thus enabling more efficient amplification and / or generation of the laser beam. In particular, the caustics of the pump beam before and after reflection by the reflector can be formed identically.

[0034] In another extended embodiment, the optical device is configured such that the laser beam propagates along its propagation direction and passes through the laser-active solid. The propagation directions of the laser beam and the pump beam form an angle of less than 45° with each other in the laser-active solid. Advantageously, this results in a particularly compact optical device.

[0035] Preferably, the device has an absorber for absorbing pump radiation reflected at the reflector and guided in the opposite direction through the laser-active solid. This absorber can be actively cooled. This pump radiation, which is particularly not absorbed by the laser-active medium, can be guided to the absorber by a polarizer and / or a reflector.

[0036] In another extension of the optical device, the pump source has a stabilizing element for stabilizing the wavelength of the pump beam. This advantageously results in higher efficiency of optical pumping. The spectrum of the pump beam can have a half-width of up to 5 nm, particularly 3 nm or 2 nm. The stabilizing element can be, in particular, a grating, especially a volume Bragg grating. The stabilizing element can be designed as an output coupler mirror of the pump source. The stabilizing element can be a bandpass filter, especially a narrow bandpass filter, with a half-width of up to 5 nm, particularly 3 nm or 2 nm. The reflectivity of the stabilizing element for the wavelength of the pump beam can be at least 5%, particularly 10% or 15%. Attached Figure Description

[0037] Further advantages and advantageous configurations of the invention can be derived from the drawings, the specification, and the claims. All features disclosed in the drawings, the specification, and the claims, whether individually or in any desired combination thereof, may be essential to the invention. In the drawings: Figure 1 A schematic representation of an exemplary embodiment of an optical device according to the present invention is shown; Figure 2 It shows Figure 1 A schematic representation of a laser-active solid for optical devices; Figure 3 It shows Figure 1 Detailed view of Area III; and Figure 4 A schematic representation of another exemplary embodiment of the optical device according to the present invention is shown. Detailed Implementation

[0038] Figure 1 An optical device 10 is schematically shown. The optical device 10 has a laser-active solid 12, a pump radiation source 14, and a reflector 16.

[0039] Pump source 14 is a diode laser and has a laser diode 18 for generating pump beam 20. The wavelength of pump beam 20 is 885 nm. Pump source 14 has a stabilizing element 22 for stabilizing the wavelength of pump beam 20. Stabilizing element 22 is a volume Bragg grating. Stabilizing element 22 is the output coupler mirror of pump source 14. For example, the reflectivity of stabilizing element 22 for the wavelength of pump beam 20 can be 5%. Stabilizing element 22 is a bandpass filter with a half-width of 2 nm. The spectrum of pump beam 20 has a half-width of 2 nm.

[0040] The pump beam 20 extends along the propagation direction 24 and passes through the laser-active solid 12.

[0041] The laser-active solid 12 is configured to amplify and / or generate a laser beam that is not in Figure 1 As shown in the figure, the laser-active solid 12 has a crystal structure. The laser-active solid 12 is made of Nd:YAG. The wavelength of the pump beam 20 is coordinated with the material of the laser-active solid 12, so that the laser-active solid 12 is optically pumped by the pump beam 20. For the purpose of optical pumping, the pump beam 20 passes through the laser-active solid 12. By means of optical pumping, the pump beam 20 is partially absorbed by the laser-active solid 12 due to population inversion. The remaining portion of the pump beam 20 exits the laser-active solid 12 as a transmitted pump beam 20.

[0042] Laser-active solid 12 has a lamellar structure.

[0043] The optical device 10 has a cooling device 26 for cooling the laser-active solid 12. The cooling device 26 is designed as a water-cooled device. The cooling device 26 has a first cooling plate 28 and a second cooling plate 30. The first cooling plate 28 is arranged on a first longitudinal side of the laser-active solid 12, and the second cooling plate 30 is arranged on a second longitudinal side opposite to the first longitudinal side. The cooling device 26 dissipates the heat generated in the laser-active solid 12 during amplification and / or generation of the laser beam.

[0044] Figure 2 The laser-active solid 12 is schematically shown in a view along a first longitudinal side without the first cooling plate 30. The laser-active solid 12 has a first end face 42 and a second end face 44 opposite to the first end face 42. A pump beam 20 is injected into the first end face 42 and coupled into the laser-active solid 12 at that end face. The pump beam 20 passes through the laser-active solid 12 from the first end face 42 to the second end face 44. After passing through the laser-active solid 12, the pump beam 20 exits the laser-active solid 12 at the second end face 44 as a transmitted pump beam 20.

[0045] Figure 2 A laser beam 46 is shown. The laser beam 46 extends along the propagation direction 48. The laser beam 46 enters the first end face 42 and is coupled into the laser-active solid 12 at that end face. The laser beam 46 passes from the first end face 42 through the laser-active solid 12 to the second end face 44. After passing through the laser-active solid 12, the laser beam 46 exits from the laser-active solid 12 at the second end face 44.

[0046] The propagation directions 48 of the laser beam 46 and 24 of the pump beam 20 are different from each other. The angle 50 between the propagation directions 48 of the laser beam 46 and 24 of the pump beam 20 is less than 45°. Figures 1 to 3 In the exemplary embodiment shown in the illustration, angle 50 is 15°.

[0047] For the purpose of amplifying the laser beam 46, the laser beam 46 and the pump beam 20 are superimposed within the laser-active solid 12. The amplification of the laser beam 46 is achieved by stimulated emission of the laser beam 46 and the pump beam 20 during their propagation through the laser-active solid 12.

[0048] Figure 1A reflector 16 is shown positioned behind the laser-active solid 12 along the propagation direction 24 of the pump beam 20. The reflector 16 is a plane mirror. The reflector 16 has a dielectric coating that provides high reflectivity to the pump beam 20. The reflector 16 is a wavelength-selective optical element configured to reflect the wavelength of the pump beam 20 more strongly than the wavelength of the laser beam. The reflector 16 has a reflectivity of 99.9% for the wavelength of the pump beam 20. The reflectivity of the reflector 16 for the wavelength of the laser beam is 1%.

[0049] Reflector 16 is arranged such that the pump beam 20 transmitted through the laser-active solid 12 is reflected back onto the laser-active solid 12. For optical pumping purposes, the pump beam 20 reflected by reflector 16 passes through the laser-active solid 12. This allows the pump beam 20 to pass through the laser-active solid 12 in both directions. Reflector 16 is configured to reflect the transmitted pump beam 20 such that the pump beam 20 partially overlaps with itself within the laser-active solid 12 before and after reflection by reflector 16.

[0050] For clarity, not in Figure 2 The diagram shows the reflected pump beam 20. Reflected by reflector 16, the pump beam 20 enters the second end face 44 and is coupled into the laser-active solid 12 at that end face. The reflected pump beam 20 passes from the second end face 44 through the laser-active solid 12 to the first end face 42. After passing through the laser-active solid 12, the remaining portion of the reflected pump beam 20 exits the laser-active solid 12 at the first end face 42.

[0051] Figure 3 Reflector 16 is shown. Reflector 16 is tilted relative to the transmitted pump beam 20. In other words, reflector 16 is configured such that the angle of incidence 32 of the pump beam 20 transmitted through the laser-active solid 12 relative to reflector 16 is not equal to 0°. Figure 1 and Figure 2 In the example shown, the incident angle 32 is 6°. The incident angle 32 is limited by the transmitted pump beam 20 and the vertical line 34 on the reflector 16. Additionally, the reflector 16 is configured such that the exit angle 36 of the pump beam 20 reflected by the reflector 16 is not equal to 0°. The value of the incident angle 32 is the same as the value of the exit angle 36. The exit angle 36 is limited by the reflected pump beam 20 and the vertical line 34 on the reflector 16.

[0052] Because the reflector 16 is tilted, the angle between the propagation direction 24 of the pump beam 20 and the propagation direction of the reflected pump beam 20 is 12°.

[0053] Since the incident angle 32 and the exit angle 36 are not equal to 0°, the reflected pump beam 20 enters the pump radiation source 14 with less than 3% of its power. The reflected pump beam 20 is guided to pass through the pump radiation source 14 with the remaining 97% of its power. This avoids overheating of the pump radiation source due to absorption by the reflected pump beam 20, and / or avoids changes in the wavelength of the pump beam 20 due to coupling of the reflected pump beam 20 into the pump radiation source 14.

[0054] The optical device 10 may have a first lens 38 and a second lens 40.

[0055] A first lens 38 is disposed between the pump radiation source 14 and the laser-active solid 12. The first lens 38 is configured to focus the pump beam 20 into the laser-active solid 12. The focal point of the pump beam 20 formed by the first lens 38 is located within the laser-active solid 12.

[0056] A second lens 40 is disposed between the laser-active solid 12 and the reflector 16. The second lens 40 is configured to collimate or image the transmitted pump beam 20. The pump beam 20 illuminates the reflector 16 in a collimated or imaged state.

[0057] Alternatively or additionally, the second lens 40 may be integrated into and / or formed on the reflector 16. For example, the reflector 16 itself may be bent for this purpose.

[0058] The reflector 16 can, in principle, be integrated into the laser-active solid 12, or disposed or formed on the laser-active solid 12. Therefore, the reflector is not necessarily designed as a separate component.

[0059] Figure 4 Another exemplary embodiment of the optical device is shown, wherein, in Figures 1 to 3 In exemplary embodiments and in Figure 4 In the exemplary embodiments, identical and functionally equivalent elements are represented by the same reference numerals, and in this respect, reference may be made to... Figures 1 to 3 The above description of exemplary embodiments makes it essentially only a discussion of Figure 4 Existing differences in exemplary implementations.

[0060] Reflector 16 is arranged perpendicularly to the transmitted pump beam 20. In other words, reflector 16 is configured such that the angle of incidence of the pump beam 20 transmitted through the laser-active solid 12 relative to reflector 16 is 0°. Reflector 16 is configured such that the angle of exit of the pump beam 20 reflected by reflector 16 relative to reflector 16 is 0°.

[0061] Due to the straight arrangement of reflector 16, the angle between the propagation direction 24 of pump beam 20 and the propagation direction of the reflected pump beam 20 is 0°. In other words, the propagation direction 24 of pump beam 20 and the propagation direction of the reflected pump beam 20 are parallel to each other. The propagation direction 24 of pump beam 20 and the propagation direction of the reflected pump beam 20 are opposite to each other.

[0062] The pump beam 20 generated by the pump radiation source 14 is linearly polarized. The degree of polarization of the linearly polarized pump beam 20 is 98%.

[0063] Optical device 10 includes a polarizer 52. Polarizer 52 is a thin-layer polarizer. Polarizer 52 is positioned between pump radiation source 14 and laser-active solid 12. Figure 4 In the exemplary embodiment shown, a polarizer 52 is disposed between the pump radiation source 14 and the first lens 38. The polarizer 52 is configured to filter the pump beam 20 according to its polarization, such that the pump beam 20 is linearly polarized after the polarizer 52. The polarizer 52 is configured to deflect the pump beam 20 according to its polarization.

[0064] Polarizer 52 is arranged such that the linearly polarized pump beam 20 generated by pump radiation source 14 passes through polarizer 52 without power loss.

[0065] Optical device 10 has Wave plate 54. Waveplate 54 has a fast axis and a slow axis, wherein, Waveplate 54 delays the beam component of pump beam 20, which is parallel to the slow axis polarization, by a quarter wavelength compared to the beam component of pump beam 20, which is parallel to the fast axis polarization. This indicates the wavelength of the pump beam 20.

[0066] Waveplate 54 is arranged between polarizer 52 and reflector 16. Waveplate 54 is arranged such that pump beam 20 passes through before being reflected by reflector 16. Waveplate 54 and pump beam 20 pass through after being reflected by reflector 16 Wave plate 54.

[0067] exist Figure 4 In the exemplary embodiment shown, Waveplate 54 is arranged between first lens 38 and laser active solid 12. Waveplate 54 is arranged such that when passing through After waveplate 54, the linear polarization of the pump beam 20 is converted to circular polarization. After passing through... After waveplate 54, the circularly polarized pump beam 20 passes through the laser-active solid 12 and is reflected by reflector 16. Then, the reflected pump beam 20 passes through the laser-active solid 12 and... Wave plate 54. Waveplate 54 is arranged such that the circularly polarized pump beam 20 reflected by reflector 16 passes through The waveplate 54 is then converted to linear polarization. The pump beam 20, reflected by reflector 16, passes through... The polarization phase after waveplate 54 is compared to that after passing through The polarization of the pump beam 20 before waveplate 54 is rotated by 90°. In other words, Waveplate 54 is configured to change the polarization of the pump beam 20, so that when passing through... The linear polarization of the pump beam 20 before waveplate 54 and the pump beam 20 reflected by reflector 16 in the path through The linear polarizations after waveplate 54 are orthogonal to each other.

[0068] The pump beam 20, reflected by reflector 16, passes through The waveplate 54 then passes into the polarizer 52. The polarizer 52 is configured to filter the pump beam 20 reflected by the reflector 16 according to the polarization of the pump beam 20, such that the pump beam 20 reflected by the reflector 16 enters the pump radiation source 14 with less than 2% of its power.

[0069] In another exemplary embodiment of the optical device (not shown), the optical device lacks a second lens. Instead of a second lens, the reflector (not shown) of the optical device has a curved surface. The reflector is configured such that the curvature of the curved surface is equal to the curvature in front of the transmitted pump beam.

[0070] In another exemplary embodiment of the optical device (not shown), the reflector is a retroreflector and is configured to reflect the pump beam transmitted through the laser-active solid back with a spatial offset. The spatial offset is configured such that the pump beam reflected by the reflector enters the pump radiation source at less than 5% of its power, particularly 3% or 2% of its power.

[0071] As is clear from the exemplary embodiments shown and illustrated, the present invention provides an optical device that enables the amplification and / or generation of laser beams with high efficiency.

Claims

1. An optical device (10) having: - a laser-active solid (12) to amplify and / or generate a laser beam (46), wherein - a slab-like configuration of laser-active solids (12), - a pump radiation source (14) to generate a pump beam (20) which propagates in a propagation direction (24) and which, for the purpose of optical pumping, passes through the laser-active solids (12), - a reflector (16) which is arranged behind the laser-active solids (12) in the propagation direction (24) of the pump beam (20) and which is configured for reflecting the pump beam (20) which is transmitted through the laser-active solids (12) back onto the laser-active solids (12), wherein, for the purpose of optical pumping, the pump beam (20) which is reflected by the reflector (16) passes through the laser-active solids (12).

2. The optical device (10) according to claim 1, - wherein, - wherein the reflector (16) is arranged to reflect the pump beam (20) which is transmitted through the laser-active solids (12) back with a spatial offset and / or an angular offset, - wherein the spatial offset is arranged such that the pump beam which is reflected by the reflector (16) impinges on the pump radiation source with less than 5% of its power.

3. The optical device (10) according to any one of the preceding claims, - wherein, - wherein the reflector (16) is arranged such that the angle of incidence (32) of the pump beam (20) which is transmitted through the laser-active solids (12) with respect to the reflector (16) does not equal 0°, and / or - wherein the reflector (16) is arranged such that the angle of emergence (36) of the pump beam (20) which is reflected by the reflector (16) with respect to the reflector (16) does not equal 0°.

4. The optical device (10) according to any one of the preceding claims, - wherein, - wherein the optical device (10) has a polarizer (52), - wherein the polarizer (52) is arranged between the pump radiation source (14) and the laser-active solids (12), - wherein the polarizer (52) is arranged to filter the pump beam (20) in accordance with the polarization of the pump beam, such that the pump beam (20) after the polarizer (52) has linear polarization. - wherein the optical device (10) has a wave plate (54), - wherein said a wave plate (54) is arranged between the polarizer (52) and the reflector (16), - wherein said The wave plate (54) is arranged to convert linear polarization of the pump beam (20) into circular polarization of the pump beam (20) and to convert circular polarization of the pump beam (20) into linear polarization of the pump beam (20).

5. The optical device (10) according to claim 4, - wherein, The The wave plate (54) is arranged such that the pump beam (20) passes through the wave plate (54) before being reflected by the reflector (16), and the pump beam (20) passes through the wave plate (54) after being reflected by the reflector (16). The wave plate (54) is arranged such that the pump beam (20) passes through the wave plate (54) before being reflected by the reflector (16), and the pump beam (20) passes through the wave plate (54) after being reflected by the reflector (16). The wave plate (54) is arranged such that the pump beam (20) passes through the wave plate (54) before being reflected by the reflector (16), and the pump beam (20) passes through the wave plate (54) after being 6. The optical device (10) according to any one of claims 4 to 5, - wherein, The The wave plate (54) is arranged to change the polarization of the pump beam (20) such that the linear polarization of the pump beam (20) before passing through the wave plate (54) and the linear polarization of the pump beam (20) reflected by the reflector (16) after passing through the wave plate (54) are orthogonal to each other. The wave plate (54) is arranged to change the polarization of the pump beam (20) such that the linear polarization of the pump beam (20) before passing through the wave plate (54) and the linear polarization of the pump beam (20) reflected by the reflector (16) after passing through the wave plate (54) are orthogonal to each other. The wave plate (54) is arranged to change the polarization of the pump beam (20) such that the linear polarization of the pump beam (20) before passing through the wave plate (54) and the linear polarization of 7. The optical device (10) according to any one of claims 4 to 6, - wherein, - wherein the polarizer (52) is arranged to filter the pump beam (20) which is reflected by the reflector (16) in accordance with the polarization of the pump beam, such that the pump beam (20) which is reflected by the reflector (16) impinges on the pump radiation source (14) with less than 5% of its power.

8. The optical device (10) according to any one of the preceding claims, - wherein, - wherein the reflector (16) is a wavelength-selective element which is arranged to reflect the wavelength of the pump beam (20) more strongly than the wavelength of the laser beam (46).

9. The optical device (10) according to any one of the preceding claims, - wherein, The laser-active solid (12) is formed of a material having or especially: Yb:YAG, Nd:YAG, Yb:LuAG, Yb:CaF2, Yb:CALGO, Yb:CALYO, Yb:GdCOB, Yb:Lu2O3, Yb:Sc2O3, Yb:S-FAP, Yb:GGG, Nd:YVO4, Nd:GdVO4, Yb:KGW, Yb:KYW, Yb:YLF or Yb:YALO.

10. The optical device (10) according to any one of the preceding claims, - wherein the optical device (10) has cooling means (26) for cooling the laser-active solid (12).

11. The optical device (10) according to any one of the preceding claims, - wherein, The reflector (16) has a curved surface, - wherein the reflector (16) is arranged such that the curvature of the curved surface is equal to the curvature of the front of the pump beam (20).

12. The optical device (10) according to any one of the preceding claims, - wherein, The optical device (10) is arranged such that the laser beam (46) propagates along a propagation direction (48) and through the laser-active solid (12), - wherein the propagation direction (48) of the laser beam (46) and the propagation direction (24) of the pump beam (20) form an angle (50) of less than 45° with each other in the laser-active solid (12).

13. The optical device (10) according to any one of the preceding claims, - wherein, The pump radiation source (14) has a stabilizing element (22) for wavelength stabilization of the pump beam (20).

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