Optically controlled transient plasma monolithic integrated high power microwave radiation system and method

Abstract

The application discloses an optical control transient plasma monolithic integrated high-power microwave radiation system and method, and belongs to the technical field of high-power microwave. The system comprises a ceramic substrate, an optical control plasma module, an electron emission unit and a substrate integrated waveguide integrated on the ceramic substrate. The optical control plasma module is used for generating an optical control transient plasma by means of a femtosecond laser, and comprises a gradient dielectric constant composite dielectric barrier layer structure composed of a sapphire layer, a silicon oxynitride layer, an aluminum-doped fused quartz layer, a quartz layer and a metal electrode. The sapphire layer is connected with the ceramic substrate through a eutectic welding layer to form a thermal coupling interface. A double-layer transition medium with a stepwise gradient dielectric constant is arranged between the quartz layer and the sapphire layer. A gradient ridge structure is arranged at a connecting position of the substrate integrated waveguide and the optical control plasma module, and is used for realizing mode matching from a plane wave to a three-dimensional waveguide. The system can be operated at normal temperature and pressure without a vacuum environment, and can be miniaturized to a chip level.

Description

Technical Field

[0001] This application belongs to the field of high-power microwave technology, and in particular relates to a light-controlled transient plasma monolithically integrated high-power microwave radiation system and method. Background Technology

[0002] High-power microwave radiation systems have wide applications in communications, radar, electronic warfare, and other fields. Traditional high-power microwave radiation systems are mostly assembled from discrete components, resulting in problems such as large size, heavy weight, large mechanical tolerances, and poor connection reliability, severely limiting their application in miniaturized and integrated devices. Furthermore, plasma generation in traditional systems often relies on a vacuum environment, requiring complex vacuum maintenance devices, which not only increases system complexity and maintenance costs but also reduces system mobility and environmental adaptability.

[0003] Furthermore, regarding integration, while existing substrate integrated waveguide (SIW) technology has achieved miniaturization of microwave transmission structures, key issues such as field mode mismatch and low heat dissipation efficiency still exist during integration with plasma generation modules. Traditional probe connection methods tend to introduce large lead inductance, leading to increased signal loss and failing to effectively address the localized high temperatures generated during plasma generation, thus affecting system stability and lifespan. In addition, existing dielectric barrier layer materials often employ a single material, making it difficult to simultaneously meet the combined requirements of optical transmittance, high thermal conductivity, low dielectric constant, and high breakdown field strength, thus limiting the improvement of system performance.

[0004] Furthermore, existing quartz-sapphire bilayer composite dielectric barrier layers suffer from significant interfacial refractive index mismatch: when a femtosecond laser is incident perpendicularly, the Fresnel reflection loss at the quartz-sapphire interface can reach 10%-15%, directly reducing laser energy utilization and exacerbating local thermal effects due to standing waves formed by interfacial reflection, resulting in uneven plasma density distribution and affecting the stability and consistency of microwave radiation. Simultaneously, the thermal expansion coefficients of quartz and sapphire differ significantly (quartz approximately...). Sapphire Under repeated heating by laser pulses and high-temperature cycling conditions, thermal stress concentration is prone to occur at the bonding interface, resulting in interface cracking and debonding failure, which seriously restricts the service life and environmental reliability of the system. Summary of the Invention

[0005] This application provides a light-controlled transient plasma monolithically integrated high-power microwave radiation system and method, which at least solves the problems of large size, poor stability, dependence on vacuum environment, poor field matching and low heat dissipation efficiency of high-power microwave radiation systems in related technologies, and at the same time solves the technical problems of large laser reflection loss and thermal stress mismatch at the double-layer dielectric barrier interface.

[0006] In a first aspect, embodiments of this application provide a light-controlled transient plasma monolithically integrated high-power microwave radiation system, comprising: A ceramic substrate and an optically controlled plasma module, an electron emission unit, and a substrate-integrated waveguide integrated on the ceramic substrate; The optically controlled plasma module is used to generate optically controlled transient plasma using a femtosecond laser. It comprises a gradient dielectric constant composite barrier layer structure consisting of a sapphire layer, a silicon oxynitride layer, an aluminum-doped fused silica layer, a quartz layer, and a metal electrode. One side of the sapphire layer serves as the microwave energy output terminal and is connected to the ceramic substrate via a eutectic bonding layer, forming a thermal coupling interface. The other side of the sapphire layer, after passing through a silicon oxynitride layer and an aluminum-doped fused silica layer, is connected to the quartz layer via a bonding process. The dielectric constants of the quartz layer, aluminum-doped fused silica layer, silicon oxynitride layer, and sapphire layer are 3.8, 4.2, 7.5, and 9.4, respectively, forming a continuous stepped dielectric constant gradient system to achieve a smooth refractive index transition. A metal electrode is located on the side of the quartz layer away from the sapphire layer's output terminal. The connection between the substrate integrated waveguide and the optically controlled plasma module is provided with a gradient ridge structure to achieve mode matching from the plane wave to the three-dimensional waveguide.

[0007] In a second aspect, embodiments of this application provide a method for optically controlled transient plasma monolithically integrated high-power microwave radiation, the method being applied to the optically controlled transient plasma monolithically integrated high-power microwave radiation system as described in any embodiment of the first aspect, the method comprising: In response to the incident femtosecond laser along a preset direction, after passing through the laser incident window, it sequentially passes through the sapphire layer, silicon oxynitride layer, aluminum-doped fused silica layer and quartz layer, breaking through the medium and generating femtosecond-level transient plasma; Electrons are emitted through a cone-shaped array of electron emission units and interact with the plasma to generate high-power microwaves; The high-power microwaves are coupled into the substrate integrated waveguide after mode matching through a gradient ridge structure, and their outward radiation is suppressed by a through-hole array.

[0008] The optically controlled transient plasma monolithically integrated high-power microwave radiation system and method of this application integrates the optically controlled plasma module, electron emission unit, and substrate-integrated waveguide onto the same ceramic substrate using monolithic integration technology. This miniaturizes the bulky microwave radiation system to the chip level, significantly reducing the system's size and weight, and improving its integration and mobility. The transient plasma is generated by femtosecond laser penetration of sapphire and quartz, allowing operation at room temperature and pressure without a vacuum environment, eliminating the need for complex vacuum maintenance devices and reducing system complexity and maintenance costs. The gradient ridge structure simultaneously optimizes field matching performance and thermal management efficiency, improving the system's energy conversion efficiency and lifespan.

[0009] In particular, by using a double-layer transition medium of aluminum-doped fused silica and silicon oxynitride structure, a stepwise gradient of dielectric constant and refractive index is achieved, which can reduce the laser reflection loss at the quartz-sapphire interface from 10%-15% to less than 2%, improve the laser energy utilization rate by more than 20%, and significantly increase the plasma density under the same incident power. At the same time, the gradient medium layer can gradually alleviate the difference in thermal expansion coefficient between quartz and sapphire, reduce the thermal stress concentration at the bonding interface, improve the structural reliability of the system under high temperature cycling and power fluctuation conditions, and reduce the risk of failure such as interface debonding and cracking. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of a light-controlled transient plasma monolithically integrated high-power microwave radiation system provided in an embodiment of this application; Figure 2 This is a first-view schematic diagram of the gradient ridge structure provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the optically controlled plasma module provided in the embodiments of this application; Figure 4 This is a schematic diagram of the asymmetric via array arrangement of the substrate integrated waveguide provided in the embodiments of this application; Figure 5 This is a comparison diagram of the asymmetric via array provided in the embodiments of this application and a conventional via array; Figure 6 This is a schematic flowchart of a light-controlled transient plasma monolithically integrated high-power microwave radiation method provided in an embodiment of this application.

[0012] Figure label: 1-Ceramic substrate, 2-Optical plasma module, 21-Laser incident window, 22-Quartz layer, 23-Metal electrode, 24-Sapphire layer, 25-Aluminum-doped fused silica layer, 26-Silicon oxynitride layer, 3-Electron emission unit, 31-Tip array, 4-Substrate integrated waveguide, 41-Through hole array, 42-Gradual ridge structure, 43-Thermal via, 5-Eutectic bonding layer. Detailed Implementation

[0013] The features and exemplary embodiments of various aspects of this application will be described in detail below. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only intended to explain this application and not to limit it. For those skilled in the art, this application can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this application by illustrating examples.

[0014] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0015] High-power microwave radiation systems have wide applications in communications, radar, electronic warfare, and other fields. High-power microwaves generally refer to electromagnetic waves with peak power exceeding hundreds of megawatts and frequencies ranging from 0.3 GHz to 300 GHz. Their generation relies on strong current relativistic effects or plasma transient radiation mechanisms. Among these, plasma-based microwave radiation technology has received continuous attention due to its advantages such as frequency tunability and rapid response.

[0016] Traditional high-power microwave radiation systems are mostly assembled from discrete components. Their typical architecture includes independent modules such as plasma sources, microwave resonant cavities, power couplers, and radiating antennas, which are interconnected by mechanical connections or cables. This architecture suffers from problems such as large size, heavy weight, large mechanical tolerances, and poor connection reliability, which severely limits its application in miniaturized and integrated devices.

[0017] Meanwhile, plasma generation in traditional systems largely depends on a vacuum environment. For example, devices such as vacuum diodes and virtual cathode oscillators require a certain level of vacuum to operate stably, necessitating complex vacuum maintenance devices, including vacuum pumps, sealed chambers, and vacuum monitoring instruments. These devices not only increase system complexity and maintenance costs but also reduce the system's mobility and environmental adaptability, making it difficult to deploy on airborne, shipborne, or portable platforms.

[0018] In terms of integration, while existing Substrate Integrated Waveguide (SIW) technology has achieved miniaturization of microwave transmission structures, key issues such as field mode mismatch and low heat dissipation efficiency still exist during integration with plasma generation modules. Specifically, there is a mode difference between the plane wave mode of traditional SIW and the waveguide mode of the three-dimensional resonant cavity in the plasma module. Using traditional probe connection methods easily introduces large lead inductance, leading to increased signal loss and reduced energy conversion efficiency.

[0019] Furthermore, existing dielectric barrier layer materials mostly employ a single material, such as quartz or ceramic alone. A single material cannot simultaneously meet the combined requirements of optical transmittance, high thermal conductivity, low dielectric constant, and high breakdown field strength. Even with a quartz-sapphire bilayer composite structure, the significant difference in refractive index and coefficient of thermal expansion between the two materials leads to high interface reflection loss and significant thermal stress mismatch, thus limiting laser energy utilization efficiency and long-term device reliability.

[0020] To address the problems in the related technologies, this application provides a light-controlled transient plasma monolithically integrated high-power microwave radiation system and method, which can achieve miniaturization, high stability, normal temperature and pressure operation, and excellent field matching and thermal management performance.

[0021] The light-controlled transient plasma monolithically integrated high-power microwave radiation system provided in this application will be described in detail below with reference to the accompanying drawings and through specific embodiments and application scenarios.

[0022] refer to Figure 1 This is a schematic diagram of the structure of a light-controlled transient plasma monolithically integrated high-power microwave radiation system according to an embodiment of this application. Figure 1 As shown, the optically controlled transient plasma monolithically integrated high-power microwave radiation system includes a ceramic substrate 1 and an optically controlled plasma module 2, an electron emission unit 3, and a substrate-integrated waveguide 4 integrated on the ceramic substrate 1. That is, the optically controlled plasma module 2, the electron emission unit 3, and the substrate-integrated waveguide 4 are manufactured on the same ceramic substrate 1 through a monolithic integration process, realizing the integrated system.

[0023] Specifically, the optically controlled plasma module 2 is used to generate optically controlled transient plasma through femtosecond laser. The connection between the substrate integrated waveguide 4 and the optically controlled plasma module 2 is provided with a gradient ridge structure 42 (suspended microstrip-SIW gradient ridge structure) to achieve mode matching from plane wave to three-dimensional waveguide.

[0024] Optionally, the ceramic substrate 1 is made of a high-strength, high-insulation ceramic material, selected from alumina, aluminum nitride, zirconium oxide or silicon carbide.

[0025] Figure 2 A first-view schematic diagram of the gradient ridge structure 42 is shown. The gradient ridge structure 42 is formed by tungsten paste printing or by a hole-filling process.

[0026] In this way, the light-controlled transient plasma monolithically integrated high-power microwave radiation system of this application embodiment uses ultrafast laser pulses to induce avalanche ionization in a microcavity to generate high-density transient plasma, and uses its rapidly changing time-varying current to directly radiate microwaves, and integrates it monolithically through MEMS or semiconductor processes.

[0027] Furthermore, Figure 3 A schematic diagram of the structure of the light-controlled plasma module 2 is shown. Figure 3 As shown, the optically controlled plasma module 2 includes a gradient dielectric composite barrier layer structure composed of a sapphire layer 24, a silicon oxynitride layer 26, an aluminum-doped fused silica layer 25, a quartz layer 22, and a metal electrode 23, and a laser incident window 21 as the laser incident surface of the plasma module. One side of the sapphire layer 24 is the microwave energy output end, which is connected to the ceramic substrate 1 through a eutectic bonding layer 5 to form a thermal coupling interface. On the other side of the sapphire layer 24, a silicon oxynitride layer 26 is deposited sequentially, followed by a bonded aluminum-doped fused silica layer 25, and then connected to the quartz layer 22 through a bonding process. The dielectric constants of the quartz layer 22, the aluminum-doped fused silica layer 25, the silicon oxynitride layer 26, and the sapphire layer 24 are 3.8, 4.2, 7.5, and 9.4, respectively, forming a continuous step-like gradient of dielectric constant and refractive index distribution, achieving an anti-reflection effect in the laser incident direction. A metal electrode 23 is provided on the side of the quartz layer 22 away from the output end of the sapphire layer 24. Therefore, the optically controlled plasma module 2 serves as an optical window, SIW support carrier, and heat sink. The mechanism for generating optically controlled transient plasma through the optically controlled plasma module 2 is as follows: after the femtosecond laser passes through the laser incident window 21, sapphire layer 24, silicon oxynitride layer 26, aluminum-doped fused silica layer 25, and quartz layer 22, femtosecond-level transient plasma is generated. Furthermore, this system does not require a vacuum environment and can operate at room temperature and pressure.

[0028] Optionally, the metal electrode 23 is a chromium / gold composite layer, formed on the surface of the quartz layer 22 by magnetron sputtering or electron beam evaporation.

[0029] Optionally, the bonding process includes plasma-assisted bonding of PABs or high-temperature anodic bonding. The process parameters for high-temperature anodic bonding include: bonding temperature 280℃~400℃, applied DC voltage 500V~1200V, bonding pressure 0.1 MPa~1 MPa, bonding in a clean inert gas or vacuum environment, and after bonding, the voltage is turned off, and the temperature is gradually reduced to below 100℃ at a rate of 1-5℃ / min while maintaining the pressure before unloading. The bonding process for high-temperature anodic bonding is as follows: first, a vacuum is drawn to the set value, then the temperature is gradually increased. After the temperature stabilizes, a preset pressure is applied, and then a high DC voltage is applied in a stepped or ramped manner, with the bonding current monitored in real time until it reaches a stable value; after bonding, the voltage is turned off, and the temperature is gradually reduced to below 100℃ at a rate of 1-5℃ / min while maintaining the pressure before unloading.

[0030] Optionally, the quartz layer 22 has a thickness of 0.1mm-0.3mm, is made of synthetic fused silica material, has a hydroxyl content of less than 10 ppm, and undergoes chemical mechanical polishing (CMP) treatment to achieve a surface roughness Ra < 1nm and a dielectric constant of [missing value]. 3.8; The aluminum-doped fused silica layer 25 has a thickness of 50μm-150μm and is a fused silica material with an alumina doping mass ratio of 8%-12%, with a dielectric constant of 4.2, combining optical transmittance similar to quartz with a higher dielectric constant; The silicon oxynitride layer 26 has a thickness of 20μm-80μm and is prepared by plasma-enhanced chemical vapor deposition (PECVD). It is a silicon oxynitride thin film with a silicon-oxygen-nitrogen element molar ratio of 1:0.6:0.8 and a dielectric constant of 7.5, which can achieve a smooth transition to the dielectric constant of sapphire; The sapphire layer 24 has a thickness of 0.5mm-1.0mm and is made of sapphire alumina single crystal wafer. Its thermal conductivity is about 35 W / m·K and its dielectric constant is about 9.4.

[0031] Therefore, the optically controlled plasma module 2 is specifically fabricated and integrated to obtain the above structure through the following method: A polished sapphire wafer with a thickness of 0.5mm-1.0mm is selected as the laser incident surface; a silicon oxynitride thin film is deposited on the unpolished surface of the sapphire wafer using PECVD technology, controlling the reactive gas source ratio to obtain the target silicon-oxygen-nitrogen ratio, forming a silicon oxynitride layer with a thickness of 20μm-80μm; after plasma activation treatment of the silicon oxynitride layer surface, an aluminum-doped fused silica sheet with a thickness of 50μm-150μm is bonded to it using plasma-assisted bonding technology to form an aluminum-doped fused silica layer; and then, a plasma-assisted bonding process is applied to the surface of the aluminum-doped fused silica layer. A layer of high-purity fused silica glass with a thickness of 0.1 mm to 0.3 mm is bonded using plasma-assisted bonding (PAB) or high-temperature anodic bonding technology. On the side of the quartz layer away from the sapphire, a thin metal layer is deposited using magnetron sputtering or electron beam evaporation. The thin metal layer is a chromium / gold (Cr / Au) composite layer with a thickness of 100 nm / 500 nm, which serves as the trigger electrode for the photo-controlled plasma module 2. The prepared "sapphire-silicon oxynitride-aluminum-doped fused silica-quartz-metal electrode" composite structure is fixed to the ceramic substrate 1 by eutectic welding (Au-Sn) or adhesive bonding, so that the composite structure and the ceramic substrate form a thermal coupling interface.

[0032] In some embodiments, the electron emission unit 3 includes a cone array 31 formed on the ceramic substrate 1, which serves as an electron emission source and is equivalent to the cathode / anode of the electron emission unit 3. The cone array 31 is formed in the green ceramic layer of the ceramic substrate 1 by screen printing or via filling process using tungsten or molybdenum-manganese paste, and is fixed to the ceramic substrate 1 by high-temperature sintering.

[0033] In addition, in some embodiments, the substrate integrated waveguide 4 is provided with an asymmetrically arranged array of vias 41. Figure 4 A schematic diagram of the through-hole array arrangement is shown. Figure 4 As shown, the asymmetric arrangement includes multiple metal through holes arranged with gradient apertures or off-axis to form a non-uniform array of through holes.

[0034] Optionally, the through-hole is filled with a high thermal conductivity material or the through-hole is formed by densifying the through-holes, wherein the high thermal conductivity material is gold or silver. Figure 5 A comparison diagram of the asymmetric via array of this embodiment and a conventional via array is shown. For example... Figure 5 As shown, the thermal conductivity of the asymmetric via array is significantly better than that of the traditional via array. Therefore, combined with the heat sink function of the suspended microstrip-SIW gradient ridge structure, a highly efficient heat dissipation path is formed, effectively solving the problem of localized high temperatures and extending the system's lifespan.

[0035] The structure and fabrication process of the optically controlled transient plasma monolithically integrated high-power microwave radiation system of this application will be further described in detail below through more specific embodiments.

[0036] Example 1 In this embodiment, the light-controlled transient plasma monolithically integrated high-power microwave radiation system includes: a ceramic substrate 1, and a light-controlled plasma module 2, an electron emission unit 3, and a substrate integrated waveguide 4 integrated thereon.

[0037] The ceramic substrate 1 uses aluminum nitride (AlN) material, which has high strength, high insulation, and excellent thermal conductivity. The photo-controlled plasma module 2 has a composite dielectric barrier layer structure of "sapphire-silicon oxynitride-aluminum-doped fused silica-quartz-metal electrode". The sapphire layer 24 is made of a 1.0 mm thick sapphire wafer. One side serves as the microwave energy output end, and the other side is sequentially deposited with a 50 μm thick silicon oxynitride layer 26, bonded with a 100 μm thick aluminum-doped fused silica layer 25, and then bonded to a 0.3 mm thick quartz layer 22 by high-temperature anodic bonding technology. The aluminum-doped fused silica has an alumina doping mass ratio of 10% and a dielectric constant of approximately 4.2; the silicon oxynitride has an oxygen-nitrogen molar ratio of 1:0.6:0.8 and a dielectric constant of 7.5; the overall dielectric constant gradually changes from 3.8 in the quartz layer to 9.4 in the sapphire layer. The high-temperature anodic bonding process parameters were set as follows: bonding temperature 350℃, applied DC voltage 800V, bonding pressure 0.5MPa, bonding under a nitrogen protective atmosphere, bonding time 20min, and unloading after bonding by cooling to 80℃ at a rate of 3℃ / min. The quartz layer 22 was made of synthetic fused silica with a hydroxyl content of 5ppm, and its surface was treated with CMP to achieve Ra=0.8nm. On the side of the quartz layer 22 away from the laser incident window 21, a Cr / Au composite metal layer was deposited as a trigger electrode (metal electrode 23) using an electron beam evaporation process. The Cr layer thickness was 100nm, and the Au layer thickness was 500nm.

[0038] The lower surface of the light-controlled plasma module 2 forms a eutectic welding layer 5 through Au-Sn eutectic welding, which is connected to the ceramic substrate 1. The heat generated by the plasma is diffused laterally to the ceramic substrate 1 through the sapphire, and then conducted out to the back heat sink from the ceramic substrate 1.

[0039] The cathode / anode of the electron emission unit 3 is formed into a cone array 31 pattern in the ceramic green ceramic layer by screen printing of molybdenum-manganese (Mo-Mn) paste, and then fixed on the ceramic substrate 1 by high temperature sintering at 1600℃.

[0040] The metal vias of the substrate integrated waveguide 4 are arranged in an asymmetric manner with gradient apertures, forming an asymmetric via array 41. The vias are filled with gold as a high thermal conductivity material, forming thermal vias 43. At the connection between the substrate integrated waveguide 4 and the optically controlled plasma module 2, a gradient ridge structure 42 is provided. This structure is printed using tungsten paste and has both mode matching and heat sink functions.

[0041] Example 2 The difference between this embodiment and Embodiment 1 is as follows: the ceramic substrate 1 uses 99% alumina material; the sapphire layer 24 of the optically controlled plasma module 2 has a thickness of 1.0 mm, the silicon oxynitride layer 26 has a thickness of 80 μm, the aluminum-doped fused silica layer 25 has a thickness of 150 μm, and the quartz layer 22 has a thickness of 0.3 mm, which are bonded together by plasma-assisted bonding (PAB); the metal vias of the substrate integrated waveguide 4 are arranged in an off-axis asymmetric manner, and the vias are densely arranged to form thermal vias 43; the gradient ridge structure 42 is formed by filling vias with tungsten paste. The remaining structures and process parameters are the same as in Embodiment 1.

[0042] Therefore, the optically controlled transient plasma monolithically integrated high-power microwave radiation system of this application embodiment has at least the following beneficial technical effects: Firstly, it has a high degree of miniaturization. By using monolithic integration technology, the optically controlled plasma module, electron emission unit, and substrate integrated waveguide are manufactured on the same ceramic substrate, miniaturizing the huge microwave radiation system to the chip level, greatly reducing the system's size and weight, and improving the system's integration and mobility. Secondly, it exhibits excellent stability and reliability. The monolithic integrated structure avoids mechanical tolerance and connection problems between discrete components. The gradient transition dielectric layer mitigates the difference in thermal expansion coefficients between quartz and sapphire, reduces thermal stress concentration at the bonding interface, improves structural reliability under high-temperature cycling and power fluctuation conditions, and reduces the risk of failure such as interface debonding and cracking. At the same time, the polished quartz layer suppresses field emission dark current, and the asymmetric SIW design suppresses higher-order modes, significantly improving the stability and reliability of the system. Third, it has strong environmental adaptability. It uses femtosecond lasers to break down sapphire and quartz to generate transient plasma, which can operate at room temperature and pressure without a vacuum environment, eliminating the need for complex vacuum maintenance devices and reducing the complexity and maintenance costs of the system. Fourth, it features high synchronization and energy conversion efficiency, with laser triggering and microwave generation naturally synchronized in time and space; the gradient dielectric constant transition reduces the interface laser reflection loss from 10%-15% to less than 2%, increasing the laser energy utilization rate to over 20%, significantly increasing plasma density under the same incident power, and improving microwave radiation power; the suspended microstrip-SIW gradient ridge structure solves the mode mismatch problem from plane wave to three-dimensional waveguide, improving energy conversion efficiency; Fifth, it has excellent thermal management efficiency. The sapphire substrate has three functions: optical window, SIW support carrier and heat sink. Its high thermal conductivity can quickly dissipate the heat from the laser hot spot. The SIW through-hole array is filled with high thermal conductivity material or has dense through-holes. Combined with the heat sink function of the suspended microstrip-SIW gradient ridge structure, it forms an efficient heat dissipation path, effectively solving the problem of local high temperature and extending the service life of the system. Sixth, it has excellent field matching performance. The "thermal through-hole" structure not only solves the problem of poor heat dissipation, but also realizes the integration of the "source" and "waveguide", which optimizes the field matching performance and improves the microwave transmission efficiency.

[0043] Furthermore, this application also provides a light-controlled transient plasma monolithically integrated high-power microwave radiation method. It should be noted that the light-controlled transient plasma monolithically integrated high-power microwave radiation method can be applied to the light-controlled transient plasma monolithically integrated high-power microwave radiation system as described in any of the above embodiments.

[0044] Figure 6 A schematic flowchart of the light-controlled transient plasma monolithically integrated high-power microwave radiation method according to an embodiment of this application is shown. Figure 6 As shown, the optically controlled transient plasma monolithically integrated high-power microwave radiation method may specifically include the following steps: S601, in response to the femtosecond laser incident along a preset direction, after passing through the laser incident window, it sequentially passes through the sapphire layer, silicon oxynitride layer, aluminum-doped fused silica layer and quartz layer, breaks through the medium and generates femtosecond-level transient plasma; S602. Electrons are emitted through the cone array of the electron emission unit and interact with the plasma to generate high-power microwaves; S603. The high-power microwave is coupled into the substrate integrated waveguide after mode matching through a gradient ridge structure, and its radiation outward is suppressed by a through-hole array for higher-order modes.

[0045] The preset direction can be: Figure 1 The arrow direction is shown.

[0046] Therefore, the light-controlled transient plasma monolithically integrated high-power microwave radiation method of this application embodiment can be applied to normal temperature and pressure environments, and its stability and energy conversion efficiency are significantly improved.

[0047] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0048] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0049] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0050] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0051] In this application, "multiple" means two or more (including two).

[0052] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0053] It should also be noted that the exemplary embodiments mentioned in this application describe methods or systems based on a series of steps or apparatus. However, this application is not limited to the order of the above steps; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0054] The above description is merely a specific implementation of this application. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application.

Claims

1. A light-controlled transient plasma monolithically integrated high-power microwave radiation system, characterized in that, include: A ceramic substrate (1) and an optically controlled plasma module (2), an electron emission unit (3) and a substrate integrated waveguide (4) integrated on the ceramic substrate (1). The optically controlled plasma module (2) is used to generate optically controlled transient plasma by femtosecond laser. It includes a gradient dielectric constant composite dielectric barrier layer structure composed of a sapphire layer (24), a silicon oxynitride layer (26), an aluminum-doped fused silica layer (25), a quartz layer (22), and a metal electrode (23). One side of the sapphire layer (24) is a microwave energy output terminal and is connected to the ceramic substrate (1) through a eutectic bonding layer (5) to form a thermal coupling interface. The other side of the sapphire layer (24) is connected to the quartz layer (22) through a bonding process after passing through the silicon oxynitride layer (26) and the aluminum-doped fused silica layer (25). A metal electrode (23) is provided on the side of the quartz layer (22) away from the output terminal of the sapphire layer (24). The connection between the substrate integrated waveguide (4) and the optically controlled plasma module (2) is provided with a gradient ridge structure (42) to achieve mode matching from the plane wave to the three-dimensional waveguide.

2. The system according to claim 1, characterized in that, The electron emission unit (3) includes a cone array (31) formed on the ceramic substrate (1) for use as an electron emission source; The cone array (31) is formed in the green ceramic layer of the ceramic substrate (1) by screen printing or hole filling process using tungsten or molybdenum manganese paste.

3. The system according to claim 1, characterized in that, The substrate integrated waveguide (4) is provided with an asymmetric array of vias (41), the asymmetric arrangement including multiple metal vias arranged with gradient apertures or off-axis.

4. The system according to claim 3, characterized in that, The through-hole is filled with a high thermal conductivity material or formed by densifying the through-holes (43), wherein the high thermal conductivity material is gold or silver.

5. The system according to claim 1, characterized in that, The metal electrode (23) is a chromium / gold composite layer, which is formed on the surface of the quartz layer (22) by magnetron sputtering or electron beam evaporation.

6. The system according to claim 1, characterized in that, The ceramic substrate (1) is made of one of alumina, aluminum nitride, zirconium oxide or silicon carbide.

7. The system according to claim 1, characterized in that, The gradient ridge structure (42) is formed by printing with tungsten paste or by filling holes.

8. The system according to claim 1, characterized in that, The bonding process includes plasma-assisted bonding of PAB or high-temperature anodic bonding.

9. The system according to claim 1, characterized in that, The quartz layer (22) has a thickness of 0.1mm-0.3mm, is made of synthetic fused silica material, has a hydroxyl content of less than 10 ppm, and is treated with chemical mechanical polishing (CMP) with a surface roughness Ra<1nm. The sapphire layer (24) has a thickness of 0.5mm-1.0mm and is made of sapphire aluminum oxide single crystal wafer.

10. A method for monolithically integrated high-power microwave radiation using optically controlled transient plasma, characterized in that, The method, applied to the light-controlled transient plasma monolithically integrated high-power microwave radiation system as described in any one of claims 1 to 9, comprises: In response to the incident femtosecond laser along a preset direction, after passing through the laser incident window, it sequentially passes through sapphire, silicon oxynitride layer, aluminum-doped fused silica layer and quartz layer, breaking through the medium and generating femtosecond-level transient plasma; Electrons are emitted through a cone-shaped array of electron emission units and interact with the plasma to generate high-power microwaves; The high-power microwaves are coupled into the substrate integrated waveguide after mode matching through a gradient ridge structure, and their outward radiation is suppressed by a through-hole array.

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