A functionally graded doped slab laser device

Abstract

The application provides a function gradient doped slab laser device, and relates to the technical field of solid-state lasers.The device comprises a pump source, a pump light shaping element and a laser material.The pump light output by the pump source is guided into the laser material through the pump light shaping element, so that the pump light activates the active ions in the laser material to generate laser light.The doping concentration of the laser material satisfies a pre-set doping concentration function, which is used to represent that the materials at different positions in the laser material correspond to different doping concentrations.The technical scheme provided by the application precisely controls the doping concentration of the laser material.Under the condition that the total heat power is unchanged, the temperature distribution of the laser material along the thickness direction is closer to a uniform distribution state, the thermal gradient and thermal effect of the laser material can be reduced, the thermal deformation and thermal stress of the laser material caused by the temperature gradient can be reduced, and the stability and reliability of the function gradient doped slab laser device in operation can be improved.

Description

Technical Field

[0001] This application belongs to the field of solid-state laser technology, and particularly relates to a function gradient doped slab laser device. Background Technology

[0002] In the field of high-power, high-beam-quality lasers, the laser gain medium plays a crucial role, and its selection and design significantly impact the laser's performance and stability. Compared to traditional bar lasers, slab lasers offer a larger heat dissipation area, allowing them to withstand higher pump power and waste heat. Furthermore, they can employ a unique zigzag optical path for laser transmission and gain, compensating for low-order aberrations caused by thermo-optical effects. Therefore, they are highly suitable for producing high-power, high-beam-quality laser output.

[0003] In slab lasers, the waste heat generated within the slab medium, along with the resulting thermal gradient and thermal stress, are key factors affecting the upper limit of the slab's output power and beam quality, directly impacting the laser's operational stability and lifespan. During high-power laser output, high-power waste heat is generated within the slab. If the slab is uniformly doped, the pump light exhibits exponential absorption and volumetric heating as it propagates along the thickness direction. However, cooling of the slab occurs at the boundaries between its two surfaces. This results in a temperature distribution along the thickness direction where the temperature is highest at the center and gradually decreases towards the larger surfaces, creating a complex thermal gradient. This leads to thermal deformation, thermal stress, and other thermal effects, ultimately affecting the beam quality of the output laser and, in severe cases, causing the slab to break. Summary of the Invention

[0004] This application provides a function gradient doped slab laser device to address the problem that the temperature distribution along the thickness direction of the slab exhibits a state where the temperature is highest at the center and gradually decreases from the center to the surface, forming a complex thermal gradient. This causes thermal deformation, thermal stress, and other thermal effects on the slab, thereby affecting the beam quality of the output laser.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, embodiments of this application provide a function gradient doped slab laser device, the device comprising: a pump source, a pump light shaping element, and a laser material; The pump source is used to output pump light; The pump light shaping element is located in the propagation path of the pump light and is used to guide the pump light into the laser material; The pump light enters the laser material through the incident surface of the laser material, and the pump light activates the active ions in the laser material to generate laser light; The doping concentration of the laser material satisfies a pre-set doping concentration function, which indicates that different doping concentrations correspond to different positions of the material in the laser material.

[0006] Optionally, the doping concentration function is generated based on the exponential absorption law and the lath cooling heat transfer formula, satisfying the following heat conduction formula:

[0007] in, Let be the thickness direction coordinates of the laser material. For temperature, Let be a function of the doping concentration. The derivative of the doping concentration function is given by [the derivative of the doping concentration function]. For pump light power, σ The stimulated emission cross section is the doped ion cross section in the laser material. k The thermal conductivity of the laser material is given.

[0008] Optionally, the incident surface of the laser material is provided with a pump light antireflection coating, and the incident surface of the laser material is the plane of the laser material close to the pump light shaping element; The reflective surface of the laser material is provided with a pump light high-reflectivity film, and the reflective surface of the laser material is the plane of the laser material away from the pump light shaping element.

[0009] Optionally, the device further includes: a cooling device; The cooling device is located on the side of the laser material away from the pump light shaping element; The cooling device uses a heat sink or liquid cooling method to cool the laser material.

[0010] Optionally, the pump source includes: a first pump source and a second pump source, and the pump light shaping element includes: a first pump light shaping element and a second pump light shaping element; The first pump light shaping element and the second pump light shaping element are symmetrically distributed on both sides of the laser material; The first pump source is located on the side of the first pump light shaping element away from the laser material; The second pump source is located on the side of the second pump light shaping element away from the laser material.

[0011] Optionally, the doping concentration function represents the doping concentration of the laser material, which is symmetrically distributed on both sides of the horizontal plane where the center of the laser material is located, and the temperature difference between the center and the edge of the laser material is minimal.

[0012] Optionally, the laser material is provided with a pump light anti-reflection film on the planes of the first pump light shaping element and the second pump light shaping element.

[0013] Optionally, the device further includes: a first cooling device and a second cooling device; The first cooling device is located between the first pump light shaping element and the laser material; The second cooling device is located between the second pump light shaping element and the laser material; The first cooling device and the second cooling device use heat sinks or liquid cooling to cool the laser material.

[0014] Optionally, the end face of the laser material is provided with a laser antireflection film, and the end face of the laser material is a plane that is perpendicular to the incident surface of the laser material and symmetrically distributed on both sides of the laser material.

[0015] Optionally, the pump source is a semiconductor laser, a solid-state laser, or a flash lamp; The pump light shaping element is a waveguide, a lens, or a lens group; The laser material is a crystal slab or a ceramic slab.

[0016] This application provides a function gradient-doped slab laser device. Through a pump light shaping element, the pump light output from the pump source is guided into the laser material, activating active ions within the laser material to generate laser light. The doping concentration of the laser material satisfies a pre-set doping concentration function, which represents the different doping concentrations at different locations within the laser material. By precisely controlling the doping concentration of the laser material, the doping concentration along the thickness direction Y can be adjusted to a functional distribution f(y). This optimizes the heat distribution within the laser material while maintaining a constant total heating power, thereby improving heat dissipation efficiency, reducing the temperature gradient, and making the temperature distribution along the thickness direction of the laser material more uniform. This further reduces the thermal gradient and thermal effects of the laser material, decreases thermal deformation and thermal stress caused by the temperature gradient, increases the upper limit of the laser material's output power, optimizes the quality of the output laser beam, and improves the stability and reliability of the function gradient-doped slab laser device. Attached Figure Description

[0017] Figure 1 A schematic diagram of a function gradient doped slab laser device provided in this application embodiment; Figure 2 A schematic diagram of another function gradient doped slab laser device provided in this application embodiment; Figure 3 A schematic diagram of another function gradient doped slab laser device provided in this application embodiment; Figure 4 A schematic diagram of another function gradient doped slab laser device provided in this application embodiment; Figure 5 Schematic diagram of temperature simulation results for two laser devices provided in the embodiments of this application; Figure 6 This is a schematic diagram of the temperature distribution along the thickness direction of two laser devices provided in the embodiments of this application. Detailed Implementation

[0018] The technical solutions of this application will be described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0019] In the field of high-power, high-beam-quality lasers, the laser gain medium plays a crucial role, and its selection and design significantly impact the laser's performance and stability. Compared to traditional bar lasers, slab lasers offer a larger heat dissipation area, allowing them to withstand higher pump power and waste heat. Furthermore, they can employ a unique zigzag optical path for laser transmission and gain, compensating for low-order aberrations caused by thermo-optical effects. Therefore, they are highly suitable for producing high-power, high-beam-quality laser output.

[0020] In slab lasers, the waste heat generated within the slab medium, along with the resulting thermal gradient and thermal stress, are key factors affecting the upper limit of the slab's output power and beam quality, directly impacting the laser's operational stability and lifespan. During high-power laser output, high-power waste heat is generated within the slab. If the slab is uniformly doped, the pump light exhibits exponential absorption along the thickness direction, resulting in a temperature distribution along the thickness direction where the center temperature is highest, gradually decreasing towards the outer surfaces. This creates a complex thermal gradient, leading to thermal deformation, thermal stress, and other thermal effects, ultimately affecting the output laser beam quality and, in severe cases, causing slab breakage. Even if the slab is doped in a gradient manner to achieve a more uniform power distribution, the cooling of the two outer surfaces will still result in an uneven, near-parabolic temperature distribution, which is also detrimental to laser output.

[0021] In summary, to generate high-power, high-beam-quality laser output, the doping concentration of the slab can be precisely controlled. While maintaining a constant total heating power, optimizing the heat distribution within the slab improves heat dissipation efficiency, reduces the temperature gradient, and makes the temperature distribution along the thickness direction more uniform. This reduces the thermal gradient and thermal effects, increases the upper limit of the slab's output power, optimizes the laser beam quality, and enhances the stability and reliability of the slab laser device, thereby achieving high-power, high-beam-quality laser output.

[0022] Therefore, this application provides a function gradient doped slab laser device that guides the pump light output from the pump source into the laser material through a pump light shaping element. This allows the pump light to activate ions within the laser material, generating laser light. The doping concentration of the laser material satisfies a pre-set doping concentration function, which represents the different doping concentrations at different locations within the laser material. By precisely controlling the doping concentration of the laser material, the doping concentration along the thickness direction Y can be adjusted to a functional distribution f(y). This optimizes the heat distribution within the laser material while maintaining a constant total heating power, thereby improving the heat dissipation efficiency, reducing the temperature gradient, and making the temperature distribution along the thickness direction more uniform. This further reduces the thermal gradient and thermal effects of the laser material, decreases thermal deformation and stress caused by the temperature gradient, increases the upper limit of the laser material's output power, optimizes the output laser beam quality, and improves the stability and reliability of the function gradient doped slab laser device.

[0023] Figure 1 This application provides a schematic diagram of the structure of a function gradient doped slab laser device, as shown in the embodiments. Figure 1 As shown, the device includes: a pump source 110, a pump light shaping element 120, and a laser material 130.

[0024] The pump source 110 can output pump light, and the pump light shaping element 120 can be located in the propagation path of the pump light, thereby guiding the pump light into the laser material 130. Accordingly, the pump light can enter the laser material 130 through the incident surface of the laser material 130, and the pump light activates the active ions in the laser material 130 to generate laser light.

[0025] Moreover, the doping concentration of the laser material 130 satisfies a pre-set doping concentration function, which can indicate that different doping concentrations correspond to different positions of the material in the laser material 130.

[0026] For example, when the function gradient doped slab laser device includes only one pump source 110 and one pump light shaping element 120, the heat distribution of the laser material 130 is caused by the pump light passing through the laser material 130 and then reflecting back through the laser material 130. Therefore, the doping concentration function corresponding to the laser material 130 is generated according to the exponential absorption law, the heat conduction cooling law, and the requirement for temperature uniformity. The embodiments of this application do not specifically limit the generation method of the doping concentration function.

[0027] Furthermore, when the function gradient doped slab laser device includes only one pump source 110 and one pump light shaping element 120, the incident surface of the laser material 130 can be provided with a pump light antireflection coating, and the reflecting surface of the laser material 130 can be provided with a pump light high reflectivity coating.

[0028] The incident surface of the laser material 130 can be the plane of the laser material 130 close to the pump light shaping element 120, and the reflecting surface of the laser material 130 can be the plane of the laser material 130 away from the pump light shaping element 120.

[0029] Specifically, after the pump source 110 emits pump light, the pump light can propagate to the laser material 130 through the pump light shaping element 120, and enter the laser material 130 through the incident surface of the laser material 130, combined with the pump light antireflection film, thereby activating the activated ions in the laser material 130 to generate laser light.

[0030] Moreover, after the pump light reaches the reflective surface of the laser material 130, it can be reflected by the reflective surface and the pump light high-reflectivity film coated on the reflective surface, so that the reflected pump light can reactivate the activated ions in the laser material 130, thereby generating laser light a second time.

[0031] Further, see Figure 2 , Figure 2 This is a schematic diagram of another function gradient doped slab laser device provided in an embodiment of this application. Since the pump light generates heat during the process of activating the laser material 130 to generate laser, the device may also include a cooling device 140.

[0032] The cooling device 140 can be located on the side of the laser material 130 away from the pump light shaping element 120. Moreover, the cooling device 140 can cool the laser material 130 by means of a heat sink or liquid cooling.

[0033] For example, the cooling device 140 can be tightly connected to the laser material 130, thereby providing cooling for the laser material 130. Moreover, the cooling method of the cooling device 140 can be direct liquid cooling of the reflective surface and microchannel heat sink, wherein the boundary condition of the direct liquid cooling surface is a convection boundary condition, while the surface cooled by the microchannel heat sink is a temperature boundary condition or a heat flux density boundary condition.

[0034] It should be noted that, in practical applications, in addition to setting different film layers on the incident and reflecting surfaces of the laser material 130, a laser antireflection film can also be provided on the end face of the laser material 130 so that the laser beam can be emitted from the end face of the laser material 130 after reaching the energy threshold.

[0035] The end face of the laser material 130 can be a plane that is perpendicular to the incident surface of the laser material 130 and symmetrically distributed on both sides of the laser material 130.

[0036] Furthermore, the pump source 110 can be a semiconductor laser, a solid-state laser, or a flash lamp, the pump light shaping element 120 can be a waveguide, a lens, or a lens group, and the laser material 130 can be a crystal slab or a ceramic slab. This application embodiment does not specifically limit the types of the pump source 110, the pump light shaping element 120, and the laser material 130.

[0037] If the laser material 130 is a crystal slab, the doping concentration function of the laser material 130 can be satisfied by adjusting the crystal growth parameters; if the laser material 130 is a ceramic slab, the doping concentration function of the laser material 130 can be satisfied by adjusting the powder concentration during the ceramic sintering process.

[0038] For example, laser material 130 can be yttrium aluminum garnet (YAG), yttrium vanadate (YVO4), sapphire, lithium yttrium fluoride (YLF), yttrium aluminate (YAP), and lutetium aluminum garnet (LuAG), etc., and the doping activating ions in laser material 130 can be rare earth ions, including neodymium ions (Nd). 3+ ), ytterbium ions (Yb 3+ Thulium ions (Tm 3+ ) and holmium ions (Ho 3+ At least one of the activating ions in ).

[0039] In one alternative embodiment, see Figure 3 , Figure 3 This is a schematic diagram of another function gradient doped slab laser device provided in an embodiment of this application. The pump source 110 may include: a first pump source 111 and a second pump source 112. The pump light shaping element 120 includes: a first pump light shaping element 121 and a second pump light shaping element 122.

[0040] The first pump light shaping element 121 and the second pump light shaping element 122 can be symmetrically distributed on both sides of the laser material 130. Correspondingly, the first pump source 111 can be located on the side of the first pump light shaping element 121 away from the laser material 130, while the second pump source 112 can be located on the side of the second pump light shaping element 122 away from the laser material 130.

[0041] Specifically, the first pump source 111 can emit a first pump light, which can enter the laser material 130 through the first pump light shaping element 121 to excite the laser; similarly, the second pump source 112 can emit a second pump light, which can enter the laser material 130 through the second pump light shaping element 122 to excite the laser.

[0042] Furthermore, the laser material 130 is provided with a pump light anti-reflection film on the planes close to the first pump light shaping element 120 and the second pump light shaping element 120, so as to increase the amount of pump light entering the laser material 130.

[0043] Furthermore, unlike a function-gradient-doped slab laser device that includes only one pump source 110 and one pump light shaping element 120, for a function-gradient-doped slab laser device that includes two pump sources 110 and two pump light shaping elements 120, the doping concentration of the laser material 130 can be distributed symmetrically within the laser material 130. For example, the doping concentration function can indicate that the doping concentration is symmetrically distributed on both sides of the horizontal plane where the center of the laser material 130 is located, and the temperature difference between the center and the edge of the laser material 130 is minimal.

[0044] For example, the doping concentration function f(y) can be a linear function, a quadratic function, a polynomial function, a trigonometric function, or other functions, and satisfies the following mathematical relationship: The distribution function of doping concentration along the y-direction is set as the doping concentration function f(y), the center of laser material 130 is the point where y=0, that is, the origin of the Y-direction, and the thickness of laser material 130 is 2*y0.

[0045] Accordingly, the doping concentration function can be generated based on the exponential absorption law and the lath cooling heat transfer formula, satisfying the following heat conduction formula:

[0046] in, The coordinates are along the thickness direction of the laser material. For temperature, It is a function of doping concentration. The derivative of the doping concentration function. For pump light power, σ This represents the stimulated emission cross section of doped ions in the laser material.k The thermal conductivity of the laser material.

[0047] Furthermore, the boundary conditions of the heat conduction formula can be determined by the cooling conditions. In the double-sided liquid-cooled laser material 130, the most common boundary condition is the convection boundary condition:

[0048]

[0049] in, ±y 0 represents the coordinates of the two ends of the laser material 130. T(±y) 0 ） The temperature at the two boundaries of the laser material is 130. h The convective heat transfer coefficient of the coolant. T 0 represents the coolant temperature.

[0050] Therefore, based on the above equations and boundary conditions, combined with the actual situation of the pump light and the geometric dimensions of the laser material 130, a certain functional form can be determined. f(y) (The function can be a linear function, quadratic function, polynomial function, trigonometric function, or other function) Substituting it into the equation, the temperature can be calculated through computer simulation. T related f(y) The result, and then with T The principle is to minimize the temperature difference between the center and the edge. f(y) The specific value.

[0051] If the function gradient doped slab laser device includes a first pump source 111 and a second pump source 112, and the first pump light shaping element 121 and the second pump light shaping element 122 can be symmetrically distributed on both sides of the laser material 130, then f(y) satisfies f(y) = f(-y), that is, the doping concentration of the laser material 130 is symmetrically distributed about the X-axis.

[0052] Assume the pump light power of the first pump source 111 and the second pump source 112 is both P. First consider the first pump light incident from the -Y direction to the +Y direction. After absorption by the laser material 130, its power distribution P1(y) follows an exponential distribution law, i.e. ,in, It is a function of doping concentration. Let σ be the thickness direction coordinate of the laser material, and σ be the stimulated emission cross section of the activated ions of the laser material 130.

[0053] Therefore, the energy distribution after the first pump light within the slat is absorbed is as follows:

[0054] in, This is the derivative of the doping concentration function.

[0055] The heat distribution generated by the first pump light is as follows:

[0056] Where η is the heat fraction of the laser output by the activated ion, that is, the proportion of heat generated by the absorbed energy.

[0057] Similarly, the heat distribution generated by the second pump light is as follows:

[0058] The total heat distribution of laser material 130 is as follows:

[0059] The heat distribution is symmetrical about the X-axis of the laser material 130, but the heat distribution cannot directly affect the laser material 130 and the output laser. Instead, the influence of the heat distribution on the temperature distribution caused by large-area cooling should be considered simultaneously.

[0060] Considering the double-sided cooling of laser material 130, the temperature distribution of laser material 130 is given by the following one-dimensional heat conduction equation:

[0061] Where k is the thermal conductivity of laser material 130, and Q(y) is the heat distribution function of laser material 130.

[0062] The boundary conditions of the heat conduction formula are determined by the cooling conditions. In the double-sided liquid-cooled laser material 130, the most common boundary condition is the convection boundary condition, namely:

[0063]

[0064] Where h is the convective heat transfer coefficient of the coolant, and T0 is the coolant temperature.

[0065] According to the above equations, the cooling boundary conditions are as follows:

[0066]

[0067] By combining the actual situation of the pump light with the geometric dimensions of the laser material 130, a certain function form f(y) (which can be a linear function, quadratic function, polynomial function, trigonometric function or other function) is substituted into the equation. The result of f(y) related to temperature T can be calculated by computer simulation. Then, the specific value of f(y) is determined based on the principle of minimizing the difference between the center temperature and the edge temperature of T.

[0068] Based on the cooling conditions, its doping concentration function is a step function symmetric about y=0, and its distribution is as follows:

[0069] Additionally, see Figure 4 , Figure 4 This is a schematic diagram of another function gradient doped slab laser device provided in an embodiment of this application. The device may further include: a first cooling device 141 and a second cooling device 142.

[0070] The first cooling device 141 is located between the first pump light shaping element 121 and the laser material 130, and the second cooling device 142 is located between the second pump light shaping element 122 and the laser material 130.

[0071] Furthermore, the first cooling device 141 and the second cooling device 142 use heat sinks (microchannel heat sinks or macrochannel heat sinks) or liquid cooling to cool the laser material 130.

[0072] In addition, the cooling device can be made of copper alloy, aluminum alloy, diamond or other high thermal conductivity materials, and can be connected to the laser material 130 by welding, pressing, gluing or bonding. This application embodiment does not specifically limit the material for making the cooling device or the way the cooling device is connected to the laser material 130.

[0073] Furthermore, under the same pumping and cooling conditions, for Figure 4 Temperature distribution simulations were performed on a function gradient doped slab laser device and a uniformly doped slab laser device with the same size and material.

[0074] Among them, the function gradient doped slab laser device has a laser material 130 with a length of 130 mm, a width of 50 mm, and a thickness of 10 mm. The material is Yb-doped YAG crystal, and the doping concentration function f(y) is a polynomial function that is symmetrically distributed about the thickness direction of the slab. The total heating power of the laser material 130 reaches 3000 watts (W).

[0075] Furthermore, in the function gradient doped slab laser device, the doping concentration function of the laser material 130 is a step function symmetric about y=0, and its distribution is as follows:

[0076] like Figure 5 and Figure 6 As shown, Figure 5 This is a schematic diagram showing the temperature simulation results of two laser devices provided in the embodiments of this application. Figure 6A schematic diagram showing the temperature distribution along the thickness direction of the two laser devices provided in the embodiments of this application. See also... Figure 5 Compared to uniformly doped slab laser devices, the temperature distribution of the laser material 130 in the function gradient doped slab laser device is closer to a uniform state, and the center temperature is lower. See Figure 6 The blue curve (corresponding to the function gradient doped slab laser device) is about half the height of the red curve (corresponding to the uniformly doped slab laser device), and the slope of each point is lower than that of the red curve. This indicates that in the function gradient doped slab laser device, the thermal gradient of the laser material 130 is lower at the corresponding positions than that of the laser material in the uniformly doped slab laser device. This can greatly reduce the thermal deformation and thermal stress of the laser material 130, thereby reducing the adverse effects of waste heat on the laser generated by the laser material 130.

[0077] In summary, the function gradient doped slab laser device provided in this application guides the pump light output from the pump source into the laser material through a pump light shaping element, thereby activating the active ions within the laser material to generate laser light. The doping concentration of the laser material satisfies a pre-set doping concentration function, which represents the different doping concentrations corresponding to different positions within the laser material. By precisely controlling the doping concentration of the laser material, the doping concentration along the thickness direction Y can be adjusted to a functional distribution f(y). This optimizes the heat distribution within the laser material while maintaining a constant total heating power, thereby improving the heat dissipation efficiency, reducing the temperature gradient, and making the temperature distribution along the thickness direction of the laser material more uniform during operation. This further reduces the thermal gradient and thermal effects of the laser material, decreases the thermal deformation and thermal stress caused by the temperature gradient, increases the upper limit of the laser material's output power, optimizes the quality of the output laser beam, and improves the stability and reliability of the function gradient doped slab laser device.

[0078] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0079] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0080] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0081] In the embodiments provided in this application, it should be understood that the disclosed apparatus / devices and methods can be implemented in other ways. For example, the apparatus / device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0082] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0083] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0084] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0085] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0086] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A function gradient-doped slab laser device, characterized in that, The device includes: a pump source, a pump light shaping element, and a laser material; The pump source is used to output pump light; The pump light shaping element is located in the propagation path of the pump light and is used to guide the pump light into the laser material; The pump light enters the laser material through the incident surface of the laser material, and the pump light activates the active ions in the laser material to generate laser light; The doping concentration of the laser material satisfies a pre-set doping concentration function, which represents that different doping concentrations correspond to different positions of the material in the laser material. The doping concentration function is generated based on the exponential absorption law and the lath cooling heat transfer formula, and satisfies the following heat conduction formula: in, Let be the thickness direction coordinates of the laser material. For temperature, Let be a function of the doping concentration. The derivative of the doping concentration function is given. The power density of the pump light, σ The stimulated emission cross section is the doped ion cross section in the laser material. k The thermal conductivity of the laser material; If the pump source includes a first pump source and a second pump source symmetrically distributed on both sides of the laser material, then the doping concentration function of the laser material is a step function symmetrical about y=0.

2. The apparatus according to claim 1, characterized in that, The incident surface of the laser material is provided with a pump light antireflection coating, and the incident surface of the laser material is the plane of the laser material close to the pump light shaping element; The reflective surface of the laser material is provided with a pump light high-reflectivity film, and the reflective surface of the laser material is the plane of the laser material away from the pump light shaping element.

3. The apparatus according to claim 1, characterized in that, The device further includes: a cooling device; The cooling device is located on the side of the laser material away from the pump light shaping element; The cooling device uses a heat sink or liquid cooling method to cool the laser material.

4. The laser device according to claim 1, characterized in that, The pump source includes: a first pump source and a second pump source, and the pump light shaping element includes: a first pump light shaping element and a second pump light shaping element; The first pump light shaping element and the second pump light shaping element are symmetrically distributed on both sides of the laser material; The first pump source is located on the side of the first pump light shaping element away from the laser material; The second pump source is located on the side of the second pump light shaping element away from the laser material.

5. The laser device according to claim 4, characterized in that, The doping concentration function represents the doping concentration of the laser material, which is symmetrically distributed on both sides of the horizontal plane where the center of the laser material is located, and the temperature difference between the center and the edge of the laser material is minimal.

6. The laser device according to claim 4, characterized in that, The laser material has a pump light antireflection film on the planes close to the first pump light shaping element and the second pump light shaping element.

7. The laser device according to claim 4, characterized in that, The device further includes: a first cooling device and a second cooling device; The first cooling device is located between the first pump light shaping element and the laser material; The second cooling device is located between the second pump light shaping element and the laser material; The first cooling device and the second cooling device use heat sinks or liquid cooling to cool the laser material.

8. The laser device according to any one of claims 1 to 7, characterized in that, The laser material has a laser antireflection coating on its end face, and the end face of the laser material is a plane that is perpendicular to the incident surface of the laser material and symmetrically distributed on both sides of the laser material.

9. The laser device according to any one of claims 1 to 7, characterized in that, The pump source is a semiconductor laser, a solid-state laser, or a flash lamp; The pump light shaping element is a waveguide, a lens, or a lens group; The laser material is a crystal slab or a ceramic slab.

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