Large-aperture pulse laser amplification gain module

Abstract

The invention discloses a large-aperture pulse laser amplification gain module, and relates to the solid laser technology, and the module comprises a fixed disc which is a disc with a plurality of through holes, and one through hole is located in the center of the disc; the gain unit comprises a gain dielectric sheet and a bracket, and the gain dielectric sheet is a circular or polygonal sheet; the support is of a barrel-shaped structure matched with the gain medium sheet in shape, and ventilation openings are formed in the periphery of the support. The rotating driving assembly comprises a rotating shaft, a fixed bearing and a rotating driving source, the cooling system comprises an annular shell, and a plurality of vent grooves are formed in the inner wall of the annular shell corresponding to the rotating path of each gain unit; the main light path comprises seed laser and pump light; and the time sequence control system is a control circuit system for controlling the time sequence of the seed laser, the pump light and the rotary driving source. The embodiment of the invention provides a novel large-aperture pulse laser amplification gain module by adopting a mode that a plurality of thin discs are tightly stacked and the module is separated and rotated.

Description

Technical Field

[0001] This application relates to the field of solid-state laser technology, and in particular to a large-aperture pulsed laser amplification gain module. Background Technology

[0002] Large-aperture pulsed laser amplification gain modules, as the core amplification unit of high-power laser systems, have become key supporting devices in high-end industrial manufacturing and medical equipment fields due to their high energy storage and peak power output capabilities provided by their large-aperture gain media. They are widely used in 100PW-level ultra-intense and ultra-short laser devices, laser weapons, proton therapy systems, precision materials processing, and other scenarios. Currently, the technical route of this type of module mainly revolves around two core principles: chirped pulse amplification (CPA) and optical parametric chirped pulse amplification (OPCPA). The mainstream approach uses large-aperture crystals or large-mode-field fibers such as Nd:YAG, Yd:YAG, LBO, and DKDP as gain media, and improves array-type diode pumping to achieve energy injection and pulse amplification.

[0003] However, as application scenarios continue to increase their demands for pulse energy (targeting hundreds of joules to kilojoules), peak power (pursuing petawatt-level breakthroughs), beam quality (requiring M2≤1.2), and repetitive operation stability, existing large-aperture pulsed laser amplification modules still face some core technical bottlenecks.

[0004] For example, thermal and nonlinear effects limit performance improvement. Quantum defects generated during high-power pumping lead to a large accumulation of heat load in the gain medium. Large-diameter gain media have long heat dissipation paths, low thermal diffusion efficiency, and are prone to thermal lensing, thermal distortion, and even stress cracking, severely degrading beam quality. Meanwhile, existing technologies have significant shortcomings in repetition rate (RFR) operation. Currently, most OPCPA systems above 100 terawatts operate in single-shot mode, with repetition rates generally below 1 Hz. However, cutting-edge research and industrial applications urgently require modules operating at repetition rates above 1 Hz. Existing pump source energy recovery speeds, gain medium relaxation characteristics, and efficient and uniform heat dissipation systems cannot meet this requirement, limiting the market application scope of these modules. Summary of the Invention

[0005] This application provides a large-aperture pulsed laser amplification gain module, which offers efficient thermal management and high reliability.

[0006] This application provides a large-aperture pulsed laser amplification and gain module, including: a fixed disk, a gain unit, a rotation drive assembly, a main optical path, a cooling system, and a time domain controller; The fixed disk is a disk with multiple through holes, one of which is located at the center of the disk; The gain unit includes a gain dielectric sheet and a support, wherein the gain dielectric sheet is circular or polygonal in shape. The bracket is a barrel-shaped structure adapted to the shape of the gain dielectric sheet to support and fix the gain dielectric sheet, and there are vents around the bracket. The rotary drive assembly includes a rotary shaft, a fixed bearing, and a rotary drive source. The cooling system includes an annular housing, and the inner wall of the annular housing has multiple ventilation slots corresponding to the path through which each gain unit rotates. The main optical path includes a seed laser and a pump light. The seed laser is a pulsed laser that will be amplified by the gain medium module, and the pump light is a laser that excites the gain medium sheet by a pump source. The timing control system is a control circuit system for controlling the timing of the seed laser, pump light, and rotary drive source. It is used to synchronously control the activation of the pump source and control the seed laser according to the rotational position of the gain medium unit on the fixed disk.

[0007] This application proposes a novel large-aperture pulsed laser amplification gain module by using a method of separating and rotating multiple thin-disc tightly stacked modules.

[0008] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0009] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the structure of the large-aperture pulsed laser amplification and gain module according to an embodiment of this application. Detailed Implementation

[0010] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0011] This application provides a large-aperture pulsed laser amplification and gain module, such as... Figure 1As shown, it includes: a fixed disk 3, a gain unit, a rotation drive assembly, a main optical path, a cooling system 6, and a time domain controller. Fixed disk 3 is a disk with multiple through holes, one of which is located at the center of the disk; Multiple gain units are provided, each including a gain dielectric sheet 1 and a support 2. The gain dielectric sheet 1 is a circular or polygonal thin sheet, with gaps between adjacent gain dielectric sheets 1. In some embodiments, the number of gain dielectric sheets 1 stacked in each gain unit is 2 to 20. In some embodiments, the disk gap between adjacent gain dielectric sheets 1 is 0.1 mm to 2 mm. For example, in some examples, the gain dielectric sheet 1 is a Yb:YAG, Nd:YAG, or Yd:YAG crystal thin sheet, and the gain medium is a crystal used to generate laser light, such as Nd:YAG, Yb:YAG, etc. The number of thin sheets is determined by factors such as the doping concentration and thickness of the thin sheets and their absorption of pump light. The gain dielectric sheet is a thin sheet with a large aperture size (tens of millimeters) and a thickness on the order of millimeters, with two main surfaces coated with optical thin films that are highly transparent to both pump light and laser light.

[0012] For example, the bracket 2 has an inner diameter of Φ50mm and a depth of 40mm. The gain medium sheet 1 is Yb:YAG, and there are 30 sheets. The disc size is Φ50×2mm. Ten sheets are grouped together to form a gain unit, which is installed in one mounting position. Both sides of each gain medium sheet 1 are coated with a double high-transmittance film for pump light 969nm and laser 1030nm.

[0013] A rotary drive assembly includes a rotary shaft 9 and a drive source 8. The rotary shaft 9 is connected to the fixed disk 3, and the drive source 8 drives the rotary shaft 9 to rotate the fixed disk 3 around its axis, causing each gain unit to periodically enter or leave the main optical path 4 region. The mounting positions are through holes formed on the fixed disk 3. An exemplary fixed disk 3 has an inner diameter of Φ30mm, an outer diameter of Φ200mm, and a thickness of 10mm. The fixed disk 3 has three through holes of Φ60mm in diameter evenly distributed at equal intervals along an inner diameter of 140mm, serving as mounting positions.

[0014] The cooling system 6 includes an annular housing, and the inner wall of the annular housing has multiple venting slots corresponding to the path through which each gain unit rotates. These venting slots guide the cooling medium to the gaps between the disks. The exemplary main optical path 4 is the light transmission path, and the cooling system 6 has a multi-semi-circular structure with an inner diameter of Φ200mm, and the inner diameter has venting slots corresponding to the disk stack.

[0015] The timing control system 10 is a control circuit system for controlling the timing of the seed laser, pump light, and rotating drive source 8. It is used to synchronously control the activation of the pump source and the seed laser based on the rotational position of the gain unit on the fixed disk 3. In some embodiments, the timing control system 10 is specifically used to ensure that the pump light emitted by the pump source and the seed laser interact appropriately in time and space and pass through the gain unit when the gain unit rotates to the main optical path region.

[0016] In some embodiments, one end of the bracket 2 is connected to and matched with the through hole; the bracket 2 is a cylindrical structure, and its inner wall is used to constrain the stacked gain dielectric sheets 1. The bracket is open to facilitate airflow through the disc spacing, and one end of the bracket is aligned with the hole position of the gain unit on the fixed disk; the gain dielectric sheets are spaced apart inside the bracket barrel, with the installation interval on the sub-millimeter level. For example, in some examples, 10 gain dielectric Yb:YAG crystal discs are fixed on the bracket 2 in a group, with a 0.5mm gap between the discs, and one end of the bracket 2 corresponds exactly to the hole position size on the fixed disk. Three brackets 2 with discs are fixed to the corresponding three through hole positions on the fixed disk 3.

[0017] In some embodiments, the rotating shaft 9 is a precision-machined shaft, circular or polygonal in shape, precisely fitted to the center hole of the fixed disk; the fixed bearing 7 is a precision bearing, ensuring that the oscillation of the fixed disk during rotation is controlled within the desired range; the rotation drive source is a precision-controlled servo motor or other precision drive source. For example, as... Figure 1 As shown, the fixed disk 3 is tightly mounted on the rotating shaft 9, which is supported by two precision fixed bearings 7, ensuring that the swing amplitude of the fixed disk 3 as it rotates with the rotating shaft 9 is controlled within the micrometer range.

[0018] One end of the fixed bearing 7 is connected to a high-precision, high-torque drive source 8 that can operate at idle speed, allowing the fixed disk 3 to rotate at a uniform speed under the drive of the drive source 8. The rotation speed ensures that the pump light 5 and the main pulse are aligned on the optical axis and occur simultaneously each time the disk stack (corresponding support) on the fixed disk 3 enters the main optical path 4. This application uses a precise timing control system 10 to control the drive source 8, the amplified laser seed source 11, the pump source, etc.

[0019] In some embodiments, the cooling system 6 includes an annular housing, the inner wall of which has multiple ventilation slots corresponding to the path traversed by each gain unit during rotation, for guiding the cooling medium into the gaps. Exemplarily, the cooling system 6 is fitted around the three supports 2 with discs, and the notch on the cooling system 6 faces the main optical path 4. In some embodiments, the cooling medium is a gas or liquid; specifically, the cooling medium can be a gas or liquid, such as helium, nitrogen, air, water, etc.

[0020] like Figure 1 As shown, when the three supports 2 with discs rotate with the fixed disk 3, at the notch where the pump light 4 and the main pulse occur, no cooling airflow blows across the gap between the discs on the supports 2, ensuring that the gain medium works in the "thermal capacity laser" working mode.

[0021] When the three supports 2 with discs move out of the notch on the cooling system 6 as the fixed plate 3 rotates, the ventilation grooves on the inner wall of the cooling system 6 begin to cool the gaps between the discs on the supports 2. The process of the discs on the supports 2 passing through the ventilation grooves on the inner wall of the cooling system 6 is the cooling process of the discs.

[0022] The laser amplification gain module of this application has the following advantages: Using thinner crystals allows for more efficient dissipation of waste heat generated during the operation of each crystal. Compared to thicker crystals, under high-power pump light, it is easier to maintain a smaller temperature difference between the inside and outside of the crystal, which is beneficial for achieving high beam quality laser output.

[0023] By stacking multiple thin crystal disks, the effective absorption of pump light by the crystal is improved. Compared to a single thin crystal requiring multi-pass absorption under high-power pump light, this method eliminates the complex optical design of multi-pass pump light reflection, simplifying the pump structure while improving pump light absorption and ensuring a certain storage capacity of the gain medium. Using multiple separate disk stacks allows the thermal stress on the gain medium during pulse amplification to be distributed across multiple disk stacks, and further distributed to each disk, achieving more efficient thermal management. The rotation of multiple separate disk stacks can be efficiently combined with the pulse repetition frequency.

[0024] By stacking multiple thin crystal disks, the gaps between the disks can be used to allow cooling gas to flow, thereby dissipating heat from the crystal. The use of a rotating gain medium allows each pulse amplification to approximate a "thermal capacity laser" operating mode, which is more conducive to maintaining high beam quality after amplification.

[0025] The discrete disk stack mode of the gain module structure in this application can be applied to amplify large-aperture beams of different sizes. The gain module design of this application can be widely used with crystals that output different wavelengths, enabling the output of high-pulse-energy lasers of a wider range of wavelengths.

[0026] It should be noted that, in the embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0027] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0028] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A large-aperture pulsed laser amplification gain module, characterized in that, include: Fixed disk, gain unit, rotary drive assembly, main optical path, cooling system, time domain controller; The fixed disk is a disk with multiple through holes, one of which is located at the center of the disk; The gain unit includes a gain dielectric sheet and a support, wherein the gain dielectric sheet is a circular or polygonal thin sheet; The bracket is a barrel-shaped structure adapted to the shape of the gain dielectric sheet to support and fix the gain dielectric sheet, and there are vents around the bracket. The rotary drive assembly includes a rotary shaft, a fixed bearing, and a rotary drive source. The cooling system includes an annular housing, and the inner wall of the annular housing has multiple ventilation slots corresponding to the path through which each gain unit rotates. The main optical path includes a seed laser and a pump light. The seed laser is a pulsed laser that will be amplified by the gain medium module, and the pump light is a semiconductor laser that excites the gain medium sheet from a pump source. The timing control system is a control circuit system for controlling the timing of the seed laser, pump light, and rotary drive source. It is used to synchronously control the activation of the pump source and control the seed laser according to the rotational position of the gain medium unit on the fixed disk.

2. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that, The fixed plate is a ring plate, with the shape and size of the central hole matching the rotation shaft; the remaining through holes are the mounting positions for the gain unit, and are evenly distributed on this ring plate.

3. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that, The gain dielectric sheet is the working material used to generate laser light, and the number of gain dielectric sheets is determined based on factors related to the absorption of pump light by the dielectric sheet.

4. The large-aperture pulsed laser amplification gain module as described in claim 3, characterized in that, The gain dielectric sheet is a thin sheet with a large diameter, on the order of tens of millimeters, and the two main surfaces of the gain dielectric sheet are coated with optical thin films that are highly transparent to both pump light and laser light.

5. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that, The bracket is open to allow airflow to pass smoothly through the disc spacing, and one end of the bracket is connected to the hole of the gain unit on the fixed plate. The gain dielectric sheets are installed at intervals within the support barrel, with the installation intervals on the sub-millimeter level.

6. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that... The rotating shaft is a precision-machined shaft, which is circular or polygonal in shape and fits precisely with the center hole of the fixed plate. The fixed bearing is a precision bearing, which allows the oscillation of the fixed disk during rotation to be controlled within the required range. The rotary drive source is a servo motor with a precisely controllable rotation speed or other precision drive source.

7. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that, The plurality of ventilation slots are used to guide the cooling medium to the disc gaps.

8. The large-aperture pulsed laser amplification and gain module as described in claim 1, characterized in that, The timing control system is specifically used to ensure that the pump light emitted by the pump source and the seed laser interact reasonably in time and space and pass through the gain unit when the gain unit rotates to the main optical path region.

9. The large-aperture pulsed laser amplification gain module as described in claim 7, characterized in that, The cooling medium is a gas or a liquid.

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