DE212012000230U1 - Attachment for an optical element of a laser - Google Patents

Abstract

A wing assembly comprising: an optical element (162) of a laser or optical amplifier, wherein the optical element (162) is cooled by a fluid stream; a wing plate (160) having an opening (160a), the optical element (162) being fixed in the opening (160a); and a retainer (170) adapted to fit between the optical element (162) and the wing plate (160) to provide a compressive force on the edge (162a) of the optical element (162) to guide the optical element (16). 162) in the opening (160a).

Description

Technical area

The present invention relates to attaching an optical element, such as a gain medium in a laser, optical amplifiers, and other types of optical systems. The fixture may be configured to cool the optical element by means of a gas or liquid stream, such as in a cryogenic gas cooled laser amplifier. The optical element may be an element that heats in operation, such as an optical amplification medium.

State of the art

High output lasers are needed for a variety of applications, such as material processing, particle acceleration, military applications, and laser-induced fusion for power generation. For these applications, lasers are needed to provide high energy repetitive rate pulses. One of the challenges associated with obtaining stable and reliable pulse generation is to handle the heat generated in optical elements of the laser. Heating may occur in a variety of components, such as optical amplification media, Pockels cells, Faraday isolators, frequency conversion stages where some degree of optical absorption occurs, and many other components in which absorbed energy is converted to heat. Conventional lasers that generate high energy pulses use water cooled or non-cooling plates as the gain medium. The pulse energy and / or the pulse repetition rate provided by such lasers is not high enough for laser-induced fusion and other applications, such as laser-driven particle accelerators.

Heat management for optical amplification media, which are arranged as plates, was investigated under a contract by the US Department of Energy, the results of which were published as "Thermal Management in Inertial Fusion Energy Slab Amplifiers", Sutton and Albrecht, Lawrence Livermore National Laboratory, 1st International Conference on Lasers for Inertial Confinement Fusion (First International Conference on Inertia Fusion Lasers) ), Monterey, Canada, May 30 - June 2, 1995 and as Sutton, SB & Albrecht, GF (1995), "Thermal management in inertial fusion energy slab amplifiers", Proceeding of the SPIE 2633, 272-281 , These publications describe the use of gas cooling of large orifice plates where the jet passes through the medium. The consequences of poor thermal management are thermally induced aberrations and thermally induced birefringence, both of which lead to a degradation in the quality of the transmitted beam. Thermally induced deformation or expansion of the gain medium can cause beam steering. In extreme cases, the thermally induced voltages can lead to breakage of the gain medium. The arrangement described by Sutton and Albrecht uses an end-pumped configuration in which the plates of the gain medium are oriented perpendicular to the pump laser beam. The pump laser beam was provided by semiconductor laser diodes. The end-pumped assembly used gain media segmented into a series of thin plates interspersed with cooling channels. Through the channels, a gas is pumped at a high speed to remove heat from the plates. As mentioned above, the pump laser beam and the emitted beam pass through the cooling medium.

A later project, known as the Mercury Laser (Mercurius Laser), is described in "Activation of the Mercury Laser: A diode-pumped solid-state laser driver for inertial fusion", Bayramian et al., Advanced Solid-State Lasers 2001 Topical Meeting and "Mercury Laser: A Diode-pumped Solid-State Laser Driver for Inertial Fusion" Tabletop Exhibit ("Advanced Solid State Laser 2001 Theme and Small Exhibition"), Seattle, Washington, 29-31. January 2001 , The project is also described in A. Bayramian et al. (2007), "The mercury project: A high average power, gas-cooled laser for inertial fusion energy development"("The Mercurius Project: A High-Gauge Gas-Cooled Laser for Inertial Fusion Energy Developments"), Fusion Science and Technology 52 ( 3), 383-387 , The project objective was to create a laser capable of producing 100 J pulses with a pulse length of 2-10 ns and a repetition rate of 10 Hz. Based on details provided in the various publications on the Mercury Laser Project 1 a schematic representation of the system for cooling the plates of gain medium. The cooling system 5 includes a heat exchanger 10 , Channels for guiding the gas flow 30 , a fan unit 20 and a laser amplifier 50 , the wing panels 60 comprising optical amplification medium plates mounted therein. Pump beam and output beam 40 are perpendicular to the plates. The heat exchanger 10 Cools the gas after it has passed the gain media. The fan unit 20 pumps the gas through the system in the direction of Laser amplifier. 2a shows the wing panels mounted in the amplifier 60 , The wing plates 60 are stacked such that the plates of reinforcing material adjacent to each other and adjacent to windows 82 lie in the amplification arrangement. A single wing panel is in 2 B shown. Around the edge of each plate 62 there is an edge trim 84 to align and support the panels in the wings. Each plate of reinforcing media 62 is using a polyurethane polymer 85 in the wing plate 60 attached to plant the plate in the wing plate. The optical amplification medium was Yb: S-FAP, which was mounted in aluminum wing plates.

Narrow column 86 between the wing plates, and between the wing plates and the assembly provide channels through which the cooling gas flows. Gas is pumped through the reinforcement assembly.

As in 2a As shown, the optical amplification medium is optically pumped by a beam perpendicular to the plane of the plates. Also the generated output beam is perpendicular to the plates. The measured wavefront output by the amplifier includes wavefront deformation as the gas heats up as it passes through the amplifier. The gas used in the cooling system was helium at a gas pressure of 4 bar within the straight channels between the wing plates. The gas velocity inside the channels is 0.1 Mach and the mass flow rate is ~ 1 g / s. The Mercury laser operated the gas at about room temperature.

There are certain advantages to operating the cooling system at lower temperatures and higher pressures than those used in the Mercury laser project. The increased temperature range and higher pressure place more demands on system design to prevent excessive vibration of the gain medium plates and to avoid gas flow interruptions. The attachment method should hold the optical amplification medium at cryogenic temperatures even from room temperature cooling and minimize thermally induced stress on the panel due to the thermal expansion differences between the wing panel and the optical amplification medium during such cooling. Further, a vibration-free method of attaching optical elements that are not gain medium is required in areas other than wing plates, which is stable over wide temperature ranges.

Summary of the invention

The present invention provides a vane assembly comprising an optical element of a laser or optical amplifier, wherein the optical element is cooled by a fluid stream; a wing plate having an opening, the optical element being fixed in the opening; and a holder configured to fit between the optical element and the wing plate to provide a compressive force on the edge of the optical element to hold the optical element in the opening. This arrangement causes edge-locking of the optical element, which avoids darkening of the optical element. The edge clamp also provides a uniform compressive clamping force around the edge of the optical element so that wavefront perturbations, such as those caused by surface clamping, are minimized. By edge of the optical element is meant the surface which is not an optical surface. This surface is normally around the circumference and perpendicular to the optical surface. For example, in the case of a circular disk-shaped optical element, the edge is a curved surface. Further, the holder of the present invention is adapted to operate at room temperature down to cryogenic temperatures because the compressive force allows for contraction or expansion differences between the wing plate and the optical element. In particular, upon cooling, the optical element may contract more than the opening in the wing panel and thereby become loose - however, the holder will continue to provide the compressive force holding the optical element in position. Depending on the materials used, the optical element may contract less than the aperture in the wing plate and be prone to breakage, however, the retainer, which is preferably elastic, will absorb the stress while still exerting sufficient compressive force to position the optical element holds. The holder of the present invention is also arranged such that the optical element can be removed by removing the holder.

The holder may fit between an outer edge of the optical element and an inner edge of the opening, wherein the holder is adapted to provide the pressing force on the edge of the optical element. A corresponding pressure force can also be exerted against the wing plate on the edge of the opening.

The holder may comprise an elastic element or a spring element. The compressive force may be provided substantially uniformly around the edge of the optical element.

The edge of the opening in the wing plate may have a groove for placing the holder. The edge of the optical element may have a groove for placing the holder. The grooves offer the advantage of aligning the optical element in the wing panel, such as centrally across the thickness of the wing panel.

The holder may extend substantially completely around the outer edge of the optical element. The holder is shaped to match the circumference of the optical element, but may be smaller in size.

The holder may have a c-shaped cross section. The holder may have a shape corresponding to that of the periphery of the optical element, wherein the holder has a smaller diameter than the optical element, thereby providing the pressing force. The holder may be split or cut across its length.

The holder may be a tension spring. The tension spring may be formed as a loop, so that it is endless. The tension spring may have a shape corresponding to that of the edge of the optical element, wherein the holder has a smaller diameter than the optical element, thereby providing the pressing force.

The holder may be a hoop having a plurality of spring-loaded contact fingers. The hoop may comprise a back plate. In the arrangement, the hoop may be arranged such that the spring fingers are in contact with the optical element.

The wing assembly may further include one or two retaining rings releasably coupled to the wing plate to retain the retainer in the opening of the wing plate. The one or both retaining rings may have an internal diameter at least as large as the inner diameter of the holder but smaller than the outer diameter of the holder.

The optical element and the wing plate may have substantially the same thickness. This prevents the coolant flow from being disturbed via the wing plate and the optical element, which can cause vibrations.

The optical element may be optical amplification medium such as Yb: YAG, Nd: YAG or other solid state laser medium suitable for optical pumping.

The present invention also provides a wing plate for mounting an optical element of a laser or optical amplifier for cooling by means of a fluid flow, the wing plate having an opening for receiving the optical element, the wing plate having a groove in the edge of the opening for receiving a holder for holding the optical element in the opening.

The present invention further provides a laser or optical amplifier comprising the wing assembly or wing plate described above. The optical element of the laser or optical amplifier may be an optical amplification medium. A pump beam may strike the optical amplification medium. The pump beam and / or output beam may be transverse to the plane of the wing assembly. The pump jet and / or output jet can pass through a cooling fluid stream.

The laser or optical amplifier may be a deep-cooled gas-cooled laser amplifier.

Although the above embodiments mount the optical element in a wing panel to form a wing assembly, other embodiments of the present invention use corresponding methods to secure the optical element into non-wing panel fasteners. In this regard, the present invention provides an optical assembly comprising: an optical element; a fastener having an opening, the optical element being fixed in the opening; and a holder configured to fit around the edge of the optical element between the optical element and the fixture to provide a compressive force on the edge of the optical element to hold the optical element in the aperture.

The holder may comprise an elastic element or a spring element.

The holder may be one of the following: a ring having a C-shaped cross section; a tension spring; and a hoop having a plurality of spring-loaded contact fingers.

Other methods and arrangements mentioned above relating to the attachment of the optical element in the wing panel may also be more generally applied to the attachment of the optical element.

Brief description of the drawings

Embodiments of the present invention, along with aspects of the prior art, will now be described with reference to the accompanying drawings, in which:

1 Figure 3 is a schematic representation of the prior art cooling system for cooling optical elements for a laser amplifier;

2a Figure 3 is an illustration of a cross-section through the prior art gas-cooled amplifier;

2 B Figure 11 is an illustration of a prior art wing plate with reinforcing medium implanted therein;

3 shows in plan view and in cross-section an optical element which is mounted in a wing plate with a holder according to the present invention;

4 a detailed cross-sectional view of three embodiments of a holder which holds the optical element in the wing plate;

5a a perspective view of a wing assembly with an optical element which is mounted in a wing plate according to the present invention; and

5b an exploded view of the wing assembly of 5a is that shows the individual components.

Detailed description

3 shows an embodiment of the present invention, in which an optical element 162 in a wing plate 160 through a holder 170 is held. The wing plate 160 may be shaped to have a cross section similar to that of the prior art as shown in FIGS 2a and 2 B is shown. The end portion of the wing plate 160 gradually tapers to merge the gas flow from between the wing plates. Other cross sections can be used. The representation in 3 shows a rectangular cross section, however, such cross sections, as described above with respect to the prior art, can be used.

The optical element 162 from 3 has a circular disc shape and is in a circular opening in the wing plate 160 added. Other forms of the optical element 162 , such as square, rectangular or elliptical, can be used. The optical element 162 is through the holder 170 held in the opening. As in the section XX of 3 shown, shows the wing plate 160 the same thickness as the optical element 162 on.

The 4a - 4c show in more detail how the holder 170 between the wing plate 160 and the optical element 162 is arranged. 4 shows three alternatives for the holder 170 , In any case, the edge of the opening includes 160a a groove 160b for picking up the holder 170 , The groove 160b may be shaped in accordance with the holder used. The illustrated optical element 162 also includes a groove 162b in the edge 162a of the disk formed as an optical element. The groove in the optical element 162 is flatter than the groove in the wing plate 160 , In other embodiments, no groove is provided in the optical element and / or no groove is provided in the wing plate edge.

However, the inclusion of the grooves is preferred to the optical element 162 in the center of the wing plate 162 align.

The arrangement of the holder 170 between the edge 160a the opening of the wing plate 160 and the edge 162a of the optical element 162 provides edge clamping of the optical element 162 ready. This is preferable to surface clamping because the opening of the optical element 162 is not obscured. The wing plate 160 and the optical element 162 have substantially the same thickness, so that the cooling fluid evenly over the surface of the wing plate 160 assembled optical element 162 flows. A difference in thickness would be a step obstruction to the cooling fluid. This could cause instabilities in the fluid and vibrations. Work has shown that the optical element 162 in the wing plate 160 should be such that the alignment tolerance between the surface of the optical element and the wing plate is less than 100 microns to ensure that disturbances in the coolant flow are minimal. This alignment tolerance between the surfaces of the optical element 162 and the wing plate 160 Also defines a maximum allowable difference in thickness between the two, so that when mounted, the orientation of the surfaces meets the criterion that the deviation is less than 100 μm.

The edge attachment method provides a small, uniform compressive force around the edge of the optical element 162 ready at room temperature. The holder 170 is sufficiently elastic to account for the contraction difference between the optical element 162 and the wing plate 160 take. For example, the optical element becomes 162 at room temperature in the wing plate 160 with the holder 170 and then cooled with pressurized helium gas as a coolant to cryogenic temperatures, for example to about 150K. The temperature drop is about 150 K. For a difference in thermal expansion coefficient of 2 × 10 ^-6 K ^-1 and a 55 mm diameter disk would give a contraction difference of about 10-20 μm, assuming that thermal expansion coefficients are constant over the temperature range. Nevertheless, the coefficients change with temperature. Assuming that the above contraction difference is of the correct order of magnitude, this would be sufficient for the optical element to be 162 breaks. The compliance of the owner 170 ensures this difference. Depending on the materials used, the difference in thermal expansion coefficients could further cause the optical element to relax. In this case, the pressing force of the holder maintains a rigid and firm support of the optical element.

To provide the small, even compressive force is the holder 170 preferably elastic, as provided by a sprung element. The 4a - 4c show three embodiments of the holder. Even though 3 a circular disk-shaped optical element 162 For example, other shapes may be used, such as square or rectangular. As will be described below, of the three embodiments, some are for certain shapes of the optical element 162 more suitable.

The first embodiment of the holder 170 is the C-ring as it is in 4a is shown. This includes a ring that matches the shape of the optical element 162 matches. The internal circumference of the ring is slightly smaller than the circumference of the ring after considering any groove. This slightly smaller size ensures the pressure on the optical element. The cross-section of the ring is of a C-shape. The ring is preferably stainless steel but other materials may be used. In addition, the ring can be cut radially at one point of the circumference, to allow a voltage reduction during cooling. A cut in the ring also allows the ring over the optical element 162 to pull and in the groove 162b to place. Because the ring with the optical element 162 is in contact with the groove continuously around the circumference (except at the cut), the C-ring uniformly sets the pressing force around the edge of the optical element 162 ready. This type of ring is best suited for circular optical elements, but properly shaped rings can also be used for optical elements having other shapes that do not have sharp corners, such as a rectangle with rounded corners.

The second embodiment of the holder 170 is the spring holder, as in 4b is shown. This consists of a tension spring whose length is slightly smaller than the circumference of the optical element 162 is. The tension spring is annular. The resistance of the spring allows it through the optical element 162 to pull and in the groove 162b to place. The internal circumference of the ring is slightly smaller than the circumference of the optical element on the groove. The slightly smaller dimension ensures a compressive force on the optical element 162 , A compressive force acts radially at each point of contact of the spring with the optical element. Thus, the multiple points around the edge of the optical element distribute the compressive force around the edge of the optical element 162 uniform. The spring is suitable for many shapes of the optical element and deforms according to the shape of the optical element 162 , The spring can also accommodate irregularities in the shape of the optical element. The spring is less suitable for sharp corners having optical elements.

4c shows a third embodiment of the holder, which takes the form of a hoop having a back plate ring with a series of spring fingers along the inner edge. The hoop may be a continuous ring or more preferably is formed from a length of finger stick. The stick can be Be: Cu stick. The spring fingers are in 5b to see. The rows of spring fingers provide multiple points of contact at the edge of the optical element, such as in the groove of the optical element. The fingers are curved in such a way that they are in the groove 162b of the optical element 162 arrange and the optical element in the opening of the wing plate 160 Center. Alternatively, the fingers may be ridge-shaped. The burr aligns with the groove and centers the optical element. Other finger shapes can also be used. The spring fingers provide a compressive force on the optical element. The multiple contact points distribute the compressive force evenly around the circumference of the optical disk. The multiple contact points can pick up irregularities. The hoop may be formed from a length of finger stick, optionally with the ends joined together to form a hoop. The finger stick may be shaped to match the shape of the optical element. The finger stick can be used to attach arbitrarily shaped discs, such as circular, square, rectangular, etc.

The cross section of the C-ring and spring holders is such that it fits on grooves with curved or circular side walls. As in the 4a and 4b shown, the C-ring and spring holders in a groove in the edge of the wing plate and the edge of the optical element arrange. The groove in the edge of the wing plate is deeper than the groove in the edge of the optical element. The groove in the edge of the wing plate is semicircular or deeper, such as a channel or a trough with a semicircular bottom. The groove in the optical element 162 is a much shallower depression.

The in 4c shown cross-section of the collar with contact fingers comprises a flat back plate with curved fingers. Therefore, the groove in the edge of the wing plate takes the form of a rectangular trench. The groove in the optical element 162 is the same flat curved recess used for the C-ring and spring retainer. Other forms of hoop or fingerstick are available so that the grooves can be shaped accordingly. For example, a curved backplate finger stick with an in 4 shown groove with a curved cross-section can be used.

In the three embodiments of the holder described above 170 the holder is in the groove in the wing plate by a separate retaining ring 180 held. 5a shows the wing assembly, wherein the optical disc 162 in the wing plate 160 is attached and the holder 170 through the retaining ring 180 is held in position. 5b is an exploded view showing each of the components of the wing assembly. The embodiment shown comprises the hoop embodiment of the holder with circular disk-shaped optical element 162 , The retaining ring is also in the cross-sectional views of 4 shown. The retaining ring 180 fits in a well 161 in the wing plate so that it does not protrude from the surface of the wing plate and obstruct the flow of coolant. The retaining ring 180 is using screws or other fasteners on the wing plate 160 attached. The outer diameter of the retaining ring 180 is larger than the outer diameter of the holder 170 to allow fixing to the wing plate. The inner diameter of the retaining ring 180 extends at least partially over the holder 170 time. As in 4c shown, the retaining ring extends 180 at least halfway across the holder, so that most of the holder is supported by the retaining ring and held in position. Depending on the geometry and type of holder used, the retaining ring may extend more or less far beyond the holder. Although the above-described embodiment relates to a circular disk-shaped optical element and an annular retaining ring, other shapes may be used for the optical element and the retaining ring.

As explained above, the pressing force on the optical element 162 through the internal diameter of the holder 180 affected. The compressive force on the optical element is also influenced by the diameter of the opening or groove 160b in which the holder 180 sitting. By producing wing plates with different groove depths or openings, the compressive force on the optical element can be adapted to the dimensions of a single optical element. Preferably, the diameter of the opening, including the depth of the groove in the wing plate, is slightly smaller than the diameter of the optical element with the holder mounted around it. This configuration causes the groove 160b the opening of the wing plate 160 presses against the holder, so that it is slightly compressed. The cooperation of this compressive force and that described above, which results from the smaller diameter of the holder compared to the optical element, securely holds the optical element in the wing plate.

The retaining ring 180 and the retaining arrangement do not form a permanent attachment, because the retaining ring 180 by removing fasteners 182 can be removed.

In some embodiments, the retaining ring is 180 not mandatory, because the holder 170 a push fit in the grooves of the optical element 162 and the wing plate 160 is. In such a case, the wing plate has no recess for attaching the retaining ring 180 on.

The holder 170 is preferably metallic, such as of stainless steel, or in the case of the hoop may consist of Be: Cu. The three embodiments of the holder 170 that in the 4a - 4c either provide multiple contact points, such as for the spring and hoop variant, or a continuous contact line, for the C-ring variant. The plurality of contact points or lines provide a thermal conduction path between the optical element 162 and the wing plate 160 ready. Heat in the optical element 162 can to the wing plate 160 be derived. Both the wing plate 160 as well as the optical element 162 are cooled by means of the fluid coolant stream. Thus, the conduction path through the holder 170 an increased effective area for convection cooling of the optical element 162 ready, which helps with the thermal gradients in the optical element 162 to reduce. For example, if the optical element 162 is a gain medium which is optically pumped, the thermal gradient produced by the absorption of the pump radiation is reduced.

In an alternative embodiment, the holder, such as the spring holder, may be made of a material having electrical resistance. This makes it possible to use the holder as a resistance heater, which can be used to compensate for external heating of the optical element. For example, a central area of the optical element becomes 162 During pumping of gain media absorb pump radiation and become hotter than the edges. By heating the edge can on this Way thermal gradients along the optical element 162 be reduced. In turn, reduced thermal gradients along the optical element provide greater uniformity of the wavefront of the beam optically moving through the device. In contrast, resistance heating in the holder can also be used by thermally induced changes in the optical element 162 current wave front to provide a beam control.

The description of the above embodiments relates to an optical element 162 which may be a disk of optical amplification medium such as YAG, Yb: S-FAP, Yb: YAG, ND: YAG or other solid state laser material suitable for optical pumping. However, the arrangements described above may be applied to other optical elements that generate heat, for example to other components in which absorbed energy is converted to heat. In addition, the assemblies may be applied to other components that are mounted in the gas stream and that are required to be held firmly in place.

In addition to the optical amplification media, examples of components that can be held using the above arrangements include Pockel cells, Faraday isolators, frequency conversion stages where some optical absorption occurs, and many other components in which absorbed energy is converted to heat is converted.

Although aluminum for the wing plate 160 Titanium is a preferred alternative because it fits better thermally to the reinforcing media described above. For example, one preferred embodiment uses a Yb-doped YAG thermal intensifier disk mounted in a titanium wing plate.

Tensile tests were performed using a rim-edge fixture at 150 K with one in an aluminum wing plate 160 fixed circular titanium disk performed. These tests indicate that the hoop holder is the more versatile variant of the three embodiments described herein. Further, an interferometric evaluation of a crystalline YAG disc affixed using the hoop holder showed minimal optical distortions using this edge clamp technique compared to a non-clamped disc.

In a further alternative embodiment, the optical element may be held in a fixture which is not a wing plate, such as a plate or casting. In such a case, the optical element is retained in an opening in the fixture using one of the methods described above. The fastening technique can be applied to any optical element that is subject to extreme temperature changes and requires an adapted and durable mounting technique to allow for differential expansion or contractions of the fixture and the optical element. For example, the optical element may be an optical window exposed to significant temperature excursions, such as from room temperature to cryogenic temperatures. The retainer does not provide a hermetic seal, however, known methods such as O-rings may additionally be used to provide a seal between one side of the optical element and the other. In other embodiments, the optical element may be an optical amplification medium that heats up but cools without external cooling.

One skilled in the art will readily appreciate that various modifications and changes may be made to the wing assembly described above without departing from the scope of the appended claims. For example, various shapes, dimensions and materials may be used. The optical element may be an optical amplification medium or another heat-generating optical element.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• "Thermal Management in Inertial Fusion Energy Slab Amplifiers", Sutton and Albrecht, Lawrence Livermore National Laboratory, 1st International Conference on Lasers for Inertial Confinement Fusion (First International Conference on Inertia Fusion Lasers) ), Monterey, Canada, May 30 - June 2, 1995 [0003]
• Sutton, SB & Albrecht, GF (1995), "Thermal management in inertial fusion energy slab amplifiers", Proceeding of the SPIE 2633, 272-281 [0003]
• "Activation of the Mercury Laser: A diode-pumped solid-state laser driver for inertial fusion", Bayramian et al., Advanced Solid-State Lasers 2001 Topical Meeting and "Mercury Laser: A Diode-pumped Solid-State Laser Driver for Inertial Fusion" Tabletop Exhibit ("Advanced Solid State Laser 2001 Theme and Small Exhibition"), Seattle, Washington, 29-31. January 2001 [0004]
• A. Bayramian et al. (2007), "The mercury project: A high average power, gas-cooled laser for inertial fusion energy development"("The Mercurius Project: A High-Gauge Gas-Cooled Laser for Inertial Fusion Energy Developments"), Fusion Science and Technology 52 ( 3), 383-387 [0004]

Claims (36)

A wing assembly comprising: an optical element ( 162 ) of a laser or optical amplifier, wherein the optical element ( 162 ) is cooled by a fluid stream; a wing plate ( 160 ), which has an opening ( 160a ), wherein the optical element ( 162 ) in the opening ( 160a ) is attached; and a holder ( 170 ), which is arranged between the optical element ( 162 ) and the wing plate ( 160 ) to provide a compressive force on the edge ( 162a ) of the optical element ( 162 ) to provide the optical element ( 162 ) in the opening ( 160a ) to keep. Arrangement according to claim 1, wherein the holder ( 170 ) between an outer edge of the optical element ( 162 ) and an inner edge of the opening ( 160a ), whereby the holder ( 170 ) is adapted to the pressure force at the edge ( 162a ) of the optical element ( 162 ). Arrangement according to claim 1 or claim 2, wherein the holder ( 170 ) comprises an elastic element or a spring element. Arrangement according to claim 2, wherein the compressive force substantially uniformly around the edge ( 162a ) of the optical element ( 162 ) or at a plurality of contact points which are substantially uniform around the edge ( 162a ) of the optical element ( 162 ) are provided. Arrangement according to one of the preceding claims, wherein the edge of the opening ( 160a ) in the wing plate ( 160 ) a groove ( 160b ) for placing the holder ( 170 ) having. Arrangement according to one of the preceding claims, wherein the edge ( 162a ) of the optical element ( 162 ) a groove ( 162b ) for placing the holder ( 170 ) having. Arrangement according to one of the preceding claims, wherein the holder ( 170 ) substantially completely around the outer edge of the optical element ( 162 ) extends around. Arrangement according to one of the preceding claims, wherein the holder ( 170 ) has a c-shaped cross-section. Arrangement according to claim 8, wherein the holder ( 170 ) has a shape similar to that of the periphery of the optical element (FIG. 162 ), the holder ( 170 ) has a smaller diameter than the optical element ( 162 ), thereby providing the pressing force. Arrangement according to one of claims 7 to 8, wherein the holder ( 170 ) is split radially. Arrangement according to one of claims 1 to 7, wherein the holder ( 170 ) is a tension spring. Arrangement according to claim 11, wherein the tension spring ( 170 ) is free of ends. Arrangement according to claim 11 or 12, wherein the tension spring has a shape which corresponds to that of the periphery of the optical element (10). 162 ), the holder ( 170 ) has a smaller diameter than the optical element ( 162 ), thereby providing the pressing force. Arrangement according to one of claims 1 to 7, wherein the holder ( 170 ) is a hoop having a plurality of spring-loaded contact fingers. Arrangement according to one of the preceding claims, comprising one or two retaining rings ( 180 ) which is detachable with the wing plate ( 160 ) are coupled to the holder ( 170 ) in the opening ( 160a ) of the wing plate ( 160 ) to keep. Arrangement according to claim 15, wherein the one or both retaining rings ( 180 ) have an internal diameter at least as large as the inner diameter of the holder ( 170 ), but smaller than the outer diameter of the holder ( 170 ). Arrangement according to one of the preceding claims, wherein the optical element ( 162 ) and the wing plate ( 160 ) have substantially the same thickness. Arrangement according to one of the preceding claims, wherein the holder ( 170 ) is metallic. Arrangement according to one of the preceding claims, wherein the holder ( 170 ) an electrical resistance for the thermal heating of the optical element ( 162 ) having. Arrangement according to one of the preceding claims, wherein the optical element ( 162 ) is a heat generating element. Arrangement according to one of the preceding claims, wherein the optical element ( 162 ) is a medium for optical amplification. An assembly according to claim 21, wherein the optical amplification medium comprises Yb: YAG, Nd: YAG or another solid state laser medium suitable for optical pumping. Arrangement according to one of the preceding claims, wherein the opening ( 160a ) and the optical element ( 162 ) are circular. Arrangement according to one of claims 1 to 23, wherein the opening ( 160a ) and the optical element ( 162 ) are square or rectangular. Wing plate ( 160 ) for fixing an optical element ( 162 ) of a laser or optical amplifier for cooling by means of a fluid flow, wherein the wing plate ( 160 ) an opening ( 160a ) for receiving the optical element ( 162 ), wherein the wing plate ( 160 ) a groove ( 160b ) in the edge of the opening ( 160a ) for receiving a holder ( 170 ) for holding the optical element ( 162 ) in the opening ( 160a ) having. Laser comprising the arrangement according to one of claims 1 to 24 or the wing plate ( 160 ) according to claim 25 and wherein the optical element ( 162 ) is a medium for optical amplification. Optical amplifier comprising the arrangement according to one of claims 1 to 24 or the wing plate ( 160 ) according to claim 25 and wherein the optical element ( 162 ) is a medium for optical amplification. A laser according to claim 26 or an optical amplifier according to claim 27, arranged such that a pumping beam impinges on the medium for optical amplification. The laser or optical amplifier of claim 26, wherein the pump beam and / or output beam is transverse to the plane of the wing assembly. A laser or optical amplifier as claimed in any one of claims 28 or 29, wherein the pump beam and / or output beam passes through a cooling fluid stream. A laser or optical amplifier according to any one of claims 28 to 30, wherein the laser is a deep-cooled gas cooled laser amplifier. An optical assembly comprising: an optical element ( 162 ); a fixture that has an opening ( 160a ), wherein the optical element ( 162 ) in the opening ( 160a ) is attached; and a holder ( 170 ), which is set up around the edge ( 162a ) of the optical element ( 162 ) around between the optical element ( 162 ) and the attachment to fit a compressive force on the edge ( 162a ) of the optical element ( 162 ) to provide the optical element ( 162 ) in the opening ( 160a ) to keep. Arrangement according to claim 32, wherein the holder ( 170 ) comprises an elastic element or a spring element. Arrangement according to claim 32 or 33, wherein the holder ( 170 ) is one of the following: a ring having a c-shaped cross section; a tension spring; and a hoop having a plurality of spring-loaded contact fingers. A laser or optical amplifier comprising the assembly of any of claims 32 to 34. The laser or optical amplifier of claim 35, wherein the laser or optical amplifier is a cryogenic gas cooled laser amplifier.

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