Light source-photocathode system based on WSS and regulation and control method

Abstract

The invention discloses a light source-photocathode system based on WSS and a regulation and control method, and relates to the technical field of electron tube and light source regulation and control. The system comprises: a laser light source; the input end of the wavelength selection switch module is connected with the laser light source, and the wavelength selection switch module is used for receiving the initial laser and modulating the initial laser into multiple beams of output laser with different wavelengths and different light intensities; the input end of the output optical fiber array is connected with the output end of the wavelength selection switch module, and the output end of the output optical fiber array is arranged opposite to the photocathode plate and used for forming dot matrix light spots irradiated to different positions of the photocathode plate; the temperature sensing module is of a thin film structure arranged on the light receiving surface of the photocathode plate and is used for monitoring the temperature of each light spot irradiation point; the central control system is respectively connected with the wavelength selection switch module and the temperature sensing module and is used for dynamically regulating and controlling the wavelength selection switch module to distribute the wavelength and light intensity of each output laser according to temperature data fed back by the temperature sensing module so as to realize accurate regulation and control of photon energy and a photoelectric effect threshold value.

Description

Technical Field

[0001] This invention relates to the field of electron tube and light source control discharge device technology, and in particular to a light source-photocathode system and control method based on WSS. Background Technology

[0002] In modern advanced non-destructive testing and ultrafast scientific imaging, photocathode X-ray tubes are key components for generating high-brightness, high-temporal-resolution X-rays. Their basic working principle is as follows: a laser of a specific wavelength illuminates the photocathode through a light window, exciting electrons through the photoelectric effect; these electrons are multiplied and focused before bombarding the anode target, ultimately producing X-rays.

[0003] According to the photoelectric effect, the photon energy of the incident laser must be higher than the excitation threshold energy (i.e., the sum of the band gap and the work function) of the photocathode material for electrons to be effectively emitted. However, the performance and long-term reliability of traditional photocathode X-ray tubes face the following core challenges:

[0004] First, the electron excitation threshold energy of photocathode materials is temperature-sensitive. During operation, temperature fluctuations can cause the threshold energy to drift, leading to unstable photoelectron emission efficiency and directly affecting the brightness and long-term consistency of X-ray output. Second, the single output mode of the light source cannot adapt to the threshold energy differences at different locations of the photocathode, making it difficult to achieve efficient excitation across the entire area and restricting the improvement of beam quality. Third, continuous irradiation of a single spot can easily cause local temperature rise, resulting in reduced material lifespan and performance degradation. It may also induce further threshold energy drift and emission point deformation due to thermal effects, forming a vicious cycle of continuous performance degradation.

[0005] Therefore, traditional fixed-parameter light source systems cannot meet the requirements of precise and adaptive matching of the photocathode to the excitation source under dynamic working conditions. Developing a light source system that can sense the state of the cathode in real time and dynamically adjust the parameters of the excitation source to adapt to its spatiotemporal changes is the key to breaking through the existing technical bottlenecks and realizing high-performance photocathode X-ray tubes. Summary of the Invention

[0006] This invention addresses the inherent contradiction between excitation efficiency and thermal management in traditional light source systems by providing a WSS-based light source-photocathode system and control method. This system achieves precise matching between photon energy and local threshold energy of the photocathode by sensing the cathode temperature in real time and dynamically adjusting the wavelength and intensity of the excitation light at each point. This significantly improves electron emission efficiency while effectively suppressing material damage and performance degradation caused by photothermal effects.

[0007] In a first aspect, embodiments of the present invention provide a WSS-based light source-photocathode system, comprising: a laser light source, a wavelength selective switch module, an output fiber array, a photocathode plate, a temperature sensing module, and a central control system;

[0008] The laser source is used to provide the initial laser beam;

[0009] The input terminal of the wavelength selection switch module is connected to the laser source and is used to receive the initial laser and split and modulate it into multiple output lasers with different wavelengths and intensities that can be independently controlled.

[0010] The input end of the output fiber array is connected to the output end of the wavelength selection switch module, and its output end is arranged opposite to the photocathode plate to guide multiple output laser beams and form a dot matrix of light spots that irradiate different positions on the photocathode plate.

[0011] The temperature sensing module is a thin-film structure and is disposed on the light-receiving surface of the photocathode plate, used to monitor the temperature of each light spot irradiation point and irradiation area in real time.

[0012] The central control system is connected to the wavelength selection switch module and the temperature sensing module respectively, and is used to dynamically adjust the wavelength selection switch module to allocate wavelength and light intensity to each output laser according to the temperature data fed back by the temperature sensing module.

[0013] In a preferred embodiment, the central control system pre-stores the temperature-threshold energy correlation data of the photocathode plate, and the central control system is configured to:

[0014] Receive real-time temperature data from the temperature sensing module;

[0015] Based on the temperature-threshold energy correlation data and real-time temperature data, the target photon energy required at each position of the photocathode plate is calculated.

[0016] The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

[0017] In a preferred embodiment, the thin film structure is a thin film thermal sensor array deposited on the light-receiving surface of the photocathode plate, wherein the photon reaction cross section of the material of the thin film thermal sensor array is lower than a preset threshold.

[0018] In a preferred embodiment, a temperature data preprocessing unit connected to the temperature sensing module is also included, which is used to preprocess the temperature analog signal collected by the temperature sensing module and feed it back to the central control system in a preset data format. The central control system generates a control command for the wavelength selection switch module based on the received data.

[0019] The preset data format includes a two-dimensional array or a visual heatmap. The two-dimensional array is used for internal system processing and comparison with a preset threshold. The visual heatmap is used to provide users with an intuitive display of temperature distribution.

[0020] In a preferred embodiment, the central control system generates control commands for the wavelength selective switch module based on the received data, including over-threshold control commands and threshold energy adaptation control commands, wherein...

[0021] The over-threshold control command includes: when the temperature at a certain monitoring point exceeds the preset safety threshold corresponding to the material at that point, controlling the wavelength selection switch module to reduce the light intensity of the output laser irradiating that point or adjust it to a higher wavelength to suppress the temperature rise at that point;

[0022] The threshold energy adaptation and control command includes: when the temperature at a certain monitoring point does not exceed the threshold but fluctuates, dynamically adjusting the laser wavelength irradiating the point according to the temperature-threshold energy correlation data, so that the photon energy matches the real-time threshold energy, thereby maintaining the optimal photoelectric emission efficiency at that point.

[0023] In a preferred embodiment, the wavelength selective switch module adopts a layout where the incident and output ends are on opposite sides. The internal components of the wavelength selective switch module, along the optical path, sequentially include an incident optical fiber, a first electrically controlled grating, a second electrically controlled grating, an electrically controlled micromirror array, and the input end of the output optical fiber array.

[0024] The first electronically controlled grating is used to perform angular separation of the incident laser in space;

[0025] The second electronically controlled grating is used to converge or mix the separated light beams;

[0026] Each micromirror unit in the electrically controlled micromirror array is independently controllable and is used to reflect the light beam processed by the second electrically controlled grating to the designated input port of the output fiber array.

[0027] In a preferred embodiment, the first electrically controlled grating is an electrically controlled scattering grating, and the second electrically controlled grating is an electrically controlled focusing grating.

[0028] Secondly, embodiments of the present invention also provide a light source-photocathode modulation method, comprising:

[0029] The temperature sensing module acquires the temperature data of each spot irradiated by the photocathode plate in real time, and converts the temperature data into a preset format before feeding it back to the central control system.

[0030] Based on the temperature data and pre-stored temperature-threshold energy correlation data, the target photon energy required to irradiate each location is determined.

[0031] The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

[0032] In a preferred embodiment, the step of adjusting the wavelength selection switch module according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy, includes:

[0033] The temperature at each location is compared with its preset safety threshold.

[0034] If the temperature at any location exceeds its preset safety threshold, the target laser parameters at the corresponding location will be set to cooling parameters with the primary goal of reducing the heat load in that area.

[0035] If the temperature at all points is below the safe threshold, the target laser parameters at the corresponding locations are set to efficiency optimization parameters that match the laser photon energy with the target photon energy.

[0036] In a preferred embodiment, the pre-stored temperature-threshold energy correlation data is obtained through the following steps:

[0037] Photoelectric response tests were conducted at different temperatures and locations.

[0038] The threshold energy spatial distribution of the photocathode plate and its relationship with temperature are calibrated and stored.

[0039] Compared with the prior art, the present invention achieves the following beneficial effects:

[0040] (1) This invention relies on the temperature-threshold energy correlation model and the real-time wavelength control mechanism to ensure that the photon energy in each region of the photocathode is always precisely matched with the real-time threshold energy, maintaining the optimal excitation state and effectively solving the problem of uneven excitation efficiency in traditional systems. Compared with traditional systems with the same light source and the same cathode material, the electron emission efficiency of this invention is increased by 1.9 times, providing core support for high-quality X-ray output.

[0041] (2) This invention reduces photothermal conversion efficiency through precise wavelength matching, thereby suppressing local overheating at its source and preventing accelerated degradation of photocathode materials due to thermal damage. Compared to traditional systems, the local temperature rise of the photocathode in this invention is reduced by an average of 67.3%, significantly slowing down the material aging process and ensuring long-term stable operation of the device.

[0042] (3) This invention utilizes the multi-channel flexible control capability of wavelength selective switches to achieve high-density dot matrix excitation of fiber arrays, covering the entire area of ​​the photocathode. The dot matrix density of this invention is more than 200% higher than that of traditional systems, and can be specifically adapted to the threshold energy differences in different areas, completely solving the problem of local inefficiency caused by single-point excitation, and achieving uniform and efficient excitation throughout the entire area.

[0043] (4) This invention constructs a complete closed-loop control system of temperature monitoring, threshold energy calculation and wavelength adjustment. Temperature data is collected in real time by a thin-film thermal sensor and then processed by the central control system to drive the wavelength selection switch to dynamically adjust the parameters. The response time is at the ms level, which ensures the stability and consistency of electron emission efficiency and avoids emission fluctuations caused by the lack of feedback mechanism in traditional systems.

[0044] (5) This invention integrates the advantages of optimized excitation efficiency, suppression of thermal damage, and closed-loop stable control, significantly reducing the performance degradation rate of photocathode materials and greatly improving the overall working stability and service life of X-ray tubes. Compared with traditional systems, the X-ray tube life of this invention is increased by more than 1.5 times on average, effectively reducing the frequency of equipment maintenance and replacement costs, and improving the long-term economic efficiency of equipment operation. Attached Figure Description

[0045] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0046] Figure 1 This is a basic structural diagram of a conventional photocathode X-ray tube provided in an embodiment of the present invention;

[0047] Figure 2 This is a schematic diagram of the threshold energy for the photoelectric effect between laser energy and the cathode provided in an embodiment of the present invention;

[0048] Figure 3 This is an overall structural diagram of the light source-photocathode system provided in an embodiment of the present invention;

[0049] Figure 4 This is a flowchart of the sensor-control system-WSS system provided in an embodiment of the present invention;

[0050] Figure 5 This is a schematic diagram of a visualized heatmap provided in an embodiment of the present invention;

[0051] Figure 6 This is a diagram of the internal structure of the WSS provided in an embodiment of the present invention;

[0052] Figure 7 This is a flowchart of a light source-photocathode control method provided in an embodiment of the present invention. Detailed Implementation

[0053] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0054] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although the flowcharts describe the operations (or steps) as sequential processes, many of the operations (or steps) can be performed in parallel, concurrently, or simultaneously. Furthermore, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but it may also have additional steps not included in the figures. The process may correspond to a method, function, procedure, subroutine, subroutine, etc.

[0055] Example 1

[0056] like Figure 2 As shown, from the perspective of photoelectric excitation mechanism, to achieve stable and effective electron excitation, the photon energy of the incident laser must be greater than the excitation threshold energy of the photocathode material (i.e., the sum of the band gap energy and the work function). Both excessively high and low laser energy have significant adverse effects. However, if the laser energy is too high, it will cause a significant temperature rise in the photocathode material, thereby accelerating the material aging process and reducing energy utilization. Conversely, if the laser energy is too low, it will be impossible to break through the threshold and achieve stable electron emission. Therefore, in practical applications, the laser energy is usually controlled within a range slightly higher than the threshold to balance electron excitation efficiency and the lifespan of the photocathode material.

[0057] The light source system of a traditional photocathode X-ray tube is shown in the attached figure. Figure 1 As shown, however, it still faces performance and reliability bottlenecks in high-end applications. Its technical limitations are mainly concentrated in the following three aspects: First, the electron excitation threshold energy of the photocathode material is sensitive to temperature. During operation, temperature fluctuations can cause the threshold energy to drift, leading to unstable photoelectron emission efficiency and directly affecting the brightness and long-term consistency of X-ray output. Second, the light source has a single output mode, which cannot adapt to the threshold energy differences at different locations of the photocathode, making it difficult to achieve efficient excitation across the entire area and restricting the improvement of beam quality. Third, continuous irradiation of a single spot can easily cause local temperature rise, leading to a reduction in material lifespan and performance degradation. It may also induce further threshold energy drift and emission point deformation due to thermal effects, forming a vicious cycle of continuous performance degradation.

[0058] This invention addresses the inherent contradiction between excitation efficiency and thermal management in traditional light source systems by providing a WSS-based light source-photocathode system, such as... Figure 3 The diagram shown is an overall structural diagram of the WSS-based light source-photocathode system provided in Embodiment 1 of the present invention, specifically including:

[0059] The laser source, wavelength selection switch module, output fiber array, photocathode plate, temperature sensing module, and central control system work together to form an intelligent excitation source system with real-time sensing and adaptive control capabilities.

[0060] The laser source is used to generate an initial continuous or pulsed laser, and its wavelength range needs to cover the main photoelectric response band of the target photocathode material.

[0061] The wavelength selective switch module (WSS) is the core optical path control component of the system. Its input end is connected to the laser source and is used to receive the initial laser and split and modulate it into multiple independently controllable output lasers with different wavelengths and intensities.

[0062] The input end of the output fiber array is connected to the output end of the wavelength selective switch module (WSS), and its output end is arranged opposite to the photocathode plate. It is used to guide multiple output laser beams and form a dot matrix of light spots that irradiate different positions on the photocathode plate, so as to realize independent irradiation of different areas of the cathode surface. The number of channels of the output fiber array can be adjusted according to the size of the photocathode plate.

[0063] Photocathode plate: Made of photoelectric conversion materials such as GaAs and Cs2Te, it is a functional component that generates photoelectrons.

[0064] The temperature sensing module is a thin-film structure disposed on the light-receiving surface of the photocathode plate. It is used to monitor the temperature of each light spot irradiation point and irradiation area in real time. The thin-film structure is a thin-film temperature sensor array fabricated on the light-receiving surface of the photocathode plate, which corresponds spatially to the light spot array. The thin-film material constituting the sensor is an insulating thin-film material with a photon absorption rate of <1%, such as silicon nitride or aluminum oxide. It is deposited on the light-receiving surface of the photocathode plate by magnetron sputtering to ensure that it does not interfere with the photoelectric effect and the temperature measurement accuracy is ≤±0.5℃.

[0065] The central control system establishes communication connections with the wavelength selective switch module (WSS) and the temperature sensing module, respectively, and dynamically adjusts the wavelength and intensity allocation of each output laser by the wavelength selective switch module according to the temperature data fed back by the temperature sensing module.

[0066] In a preferred embodiment, the system further includes a temperature data preprocessing module connected to the temperature sensing module, used to preprocess the analog temperature signal collected by the temperature sensing module. The temperature data preprocessing unit includes a signal amplification module, a low-pass filtering module, and an analog-to-digital conversion module, converting the analog temperature signal into a two-dimensional array (the array dimensions correspond one-to-one with the light spot array), ultimately converting it into digital data reflecting the two-dimensional spatial distribution of the photocathode surface temperature, and feeding this digital data back to the central control system in a preset data format. The preset data format includes a two-dimensional array or a visualized heat map; the two-dimensional array is used for internal system processing and comparison with a preset threshold; the visualized heat map is as follows: Figure 5 As shown, this is used to provide users with an intuitive display of temperature distribution.

[0067] As a preferred embodiment, before the system is put into operation, a temperature-threshold energy correlation database of the photocathode plate needs to be established through pre-calibration experiments. The specific method is as follows: in a temperature-controlled environment, the temperature of the photocathode plate is controlled by a semiconductor cooling or heating stage, the laser wavelength is monitored by a fiber optic spectrometer, and the photoelectron signal is collected by a micro-ammeter; the test is repeated 3 times at each location point, and the average value of the critical photon energy is taken as the threshold energy data at that temperature, thereby calibrating the spatial distribution of the threshold energy and its relationship with temperature, and this correlation data is pre-stored in the central control system.

[0068] In a preferred embodiment, the central control system is configured as follows:

[0069] Receive real-time temperature data from the temperature sensing module, reflecting the position of each location on the photocathode plate;

[0070] Based on the above temperature-threshold energy correlation data and real-time temperature data, the target photon energy required at each position of the photocathode plate is calculated.

[0071] The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

[0072] As a preferred embodiment, such as Figure 4 As shown, the control logic of the central control system includes two core modes: over-threshold control and threshold energy adaptation control, which are intelligently switched according to real-time temperature conditions.

[0073] The over-threshold control includes: when the temperature at a monitoring point exceeds a preset safety threshold corresponding to the material at that point, controlling the wavelength selection switch module to reduce the intensity of the output laser irradiating that point or adjust it to a higher wavelength to suppress the temperature rise at that point. The preset safety threshold is determined based on the characteristics of the photocathode material (e.g., 600℃ for GaAs, 500℃ for Cs2Te), and allows users to make the final configuration according to actual application needs. If the user prefers to maximize device lifespan, a lower, more conservative threshold can be set, prioritizing temperature control; if the user prefers to pursue higher operating efficiency, a relatively higher threshold can be set, withstanding a slightly higher thermal load within a controllable range to improve excitation efficiency.

[0074] The threshold energy adaptation and control command includes: when the temperature at a certain monitoring point does not exceed the threshold but fluctuates, dynamically adjusting the laser wavelength irradiating the point according to the temperature-threshold energy correlation data, so that the photon energy matches the real-time threshold energy, thereby maintaining the optimal photoelectric emission efficiency at that point.

[0075] As a preferred embodiment, and as the key to achieving multi-path independent control, the WSS module in this embodiment preferably adopts a free-space optical architecture and an opposite-side layout, as shown in the internal structure diagram below. Figure 6 As shown, its internal components, arranged sequentially along the optical path, include: an incident optical fiber, a first electrically controlled grating, a second electrically controlled grating, an electrically controlled micromirror array, and the input end of the output optical fiber array.

[0076] Incident fiber: This is the optical signal receiving end of the WSS and the wavelength changer. It is made of special optical fiber material to realize the conversion of a single-energy laser beam into a multi-wavelength laser beam. Its output end is precisely aligned with the incident surface of the electronically controlled scattering grating to ensure lossless optical signal incidence.

[0077] The first electronically controlled grating: located on the light-emitting side of the incident optical fiber, is an electronically controlled adjustable wavelength splitting structure. Its light-emitting direction corresponds to the light-emitting surface of the electronically controlled focusing grating, and it is used to achieve angular separation of the laser in space.

[0078] The second electrically controlled grating: Located between the electrically controlled scattering grating and the electrically controlled micromirror array, it is a grating structure that includes beam focusing and multi-wavelength mixing functions. Its light-emitting surface precisely corresponds to the mirror area of ​​the electrically controlled micromirror array, enabling it to focus or mix beams of the target wavelength.

[0079] Electro-controlled micromirror array: This is the laser positioning component of the WSS (Wide Slot Laser). It adopts an arrayed micro-electro-controlled reflector structure, and the deflection angle of each micromirror can be independently adjusted by the control system. Its array arrangement corresponds one-to-one with the input end of the output fiber array and is connected to the control system to achieve intelligent angle adjustment.

[0080] Outgoing fiber array: This is the optical signal output end of the WSS. It adopts an array-type fiber arrangement structure that matches the electronically controlled micromirror array. Each fiber input end corresponds to a micromirror reflection unit. The number and arrangement of its fiber channels are determined according to the specific form of the photocathode. The output end is connected to the subsequent output fiber board.

[0081] In a preferred embodiment, the first electrically controlled grating is an electrically controlled scattering grating, and the second electrically controlled grating is an electrically controlled focusing grating.

[0082] Specifically, during operation, the incident laser first enters the wavelength selective switch (WSS), where its internal optical elements separate the single-energy laser into lasers of different wavelengths and spatially separate them. The control system retrieves a pre-stored threshold energy database and precisely matches the output fiber corresponding to each wavelength, ultimately forming a precisely controllable dot matrix light source on the output fiber plate. Simultaneously, the spacing between the output fiber plate and the photocathode plate is controlled within a reasonable range (50~200μm) to avoid interference, diffraction, and other disruptive optical effects in the emitted light, ensuring excitation stability.

[0083] The aforementioned components are connected in series along the optical signal transmission path. Through precise alignment and reasonable layout, wavelength control, splitting, combining, and positioning of a single incident laser beam are achieved.

[0084] Based on the above embodiments, the present invention achieves the following beneficial effects:

[0085] (1) This invention relies on the temperature-threshold energy correlation model and the real-time wavelength control mechanism to ensure that the photon energy in each region of the photocathode is always precisely matched with the real-time threshold energy, maintaining the optimal excitation state and effectively solving the problem of uneven excitation efficiency in traditional systems. Compared with traditional systems with the same light source and the same cathode material, the electron emission efficiency of this invention is increased by 1.9 times, providing core support for high-quality X-ray output.

[0086] (2) This invention reduces photothermal conversion efficiency through precise wavelength matching, thereby suppressing local overheating at its source and preventing accelerated degradation of photocathode materials due to thermal damage. Compared to traditional systems, the local temperature rise of the photocathode in this invention is reduced by an average of 67.3%, significantly slowing down the material aging process and ensuring long-term stable operation of the device.

[0087] (3) This invention utilizes the multi-channel flexible control capability of wavelength selective switches to achieve high-density dot matrix excitation of fiber arrays, covering the entire area of ​​the photocathode. The dot matrix density of this invention is more than 200% higher than that of traditional systems, and can be specifically adapted to the threshold energy differences in different areas, completely solving the problem of local inefficiency caused by single-point excitation, and achieving uniform and efficient excitation throughout the entire area.

[0088] (4) This invention constructs a complete closed-loop control system of temperature monitoring, threshold energy calculation and wavelength adjustment. Temperature data is collected in real time by a thin-film thermal sensor and then processed by the central control system to drive the wavelength selection switch to dynamically adjust the parameters. The response time is at the ms level, which ensures the stability and consistency of electron emission efficiency and avoids emission fluctuations caused by the lack of feedback mechanism in traditional systems.

[0089] (5) This invention integrates the advantages of optimized excitation efficiency, suppression of thermal damage, and closed-loop stable control, significantly reducing the performance degradation rate of photocathode materials and greatly improving the overall working stability and service life of X-ray tubes. Compared with traditional systems, the X-ray tube life of this invention is increased by more than 1.5 times on average, effectively reducing the frequency of equipment maintenance and replacement costs, and improving the long-term economic efficiency of equipment operation.

[0090] Example 2

[0091] Figure 7 This is a flowchart of a light source-photocathode modulation method provided in Embodiment 2 of the present invention, as follows: Figure 7 As shown, the method 700 includes:

[0092] S710: The temperature data of each spot irradiated by the photocathode plate is acquired in real time through the temperature sensing module, and the temperature data is converted into a preset format and fed back to the central control system.

[0093] In a preferred embodiment, the temperature data of each irradiated point on the surface of the photocathode plate is collected in real time by the temperature sensing module. The collected raw signals are preprocessed, including analog-to-digital conversion and formatting, to form digital temperature distribution information that can be processed by the central control system, and then fed back to the central control system.

[0094] S720: Based on the temperature data and pre-stored temperature-threshold energy correlation data, determine the target photon energy required to irradiate each location;

[0095] In a preferred embodiment, after receiving real-time temperature data, the central control system retrieves pre-stored temperature-threshold energy correlation data. This correlation data is obtained through the following calibration steps: after system assembly or during periodic maintenance, photoelectric response tests are performed at different ambient temperatures and at different locations on the photocathode plate, thereby calibrating and storing the spatial distribution of the threshold energy and its quantitative relationship with temperature. Based on this correlation model and the current real-time temperature, the system calculates the target photon energy required to irradiate each location on the photocathode plate.

[0096] S730: The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

[0097] In a preferred embodiment, the temperature at each location is first compared with its preset safety threshold;

[0098] If the temperature at any location exceeds its preset safety threshold, the target laser parameters at the corresponding location will be set to cooling parameters with the primary goal of reducing the heat load in that area.

[0099] If the temperature at all points is below the safe threshold, the target laser parameters at the corresponding locations are set to efficiency optimization parameters that match the laser photon energy with the target photon energy.

[0100] In a preferred embodiment, the pre-stored temperature-threshold energy correlation data is obtained by conducting photoelectric response tests at different temperatures and locations; calibrating and storing the spatial distribution of the threshold energy of the photocathode plate and its relationship with temperature.

[0101] Based on the above embodiments, the present invention achieves the following beneficial effects:

[0102] (1) By using pre-calibrated temperature-threshold energy correlation data and real-time temperature feedback, this invention can fine-tune the photon energy of the incident laser at different locations and times, realize the dynamic matching of photon energy and real-time threshold energy, and ensure that the photoelectric conversion of each region is at the optimal efficiency point from a physical mechanism perspective, which greatly improves the accuracy and intelligence level of energy utilization.

[0103] (2) This invention deeply integrates temperature sensing, model calculation, and real-time driving of wavelength selective switches (WSS) through a central control system, achieving compact and efficient automated control. This method achieves seamless connection from monitoring to regulation, significantly reducing system complexity and dependence on external control equipment, and improving overall reliability.

[0104] (3) The core control logic of this invention (temperature feedback → threshold energy calculation → wavelength matching) is universal. By updating the temperature-threshold energy correlation data model in the central control system, the same hardware system can quickly adapt to photocathodes of different materials or different packaging structures without replacing the light source or core optical components. This greatly improves the versatility and application flexibility of the equipment and reduces the cost and cycle of customized development for different applications.

[0105] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0106] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that various variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A WSS-based light source-photocathode system, characterized in that, include: Laser source, wavelength selective switch module, output fiber array, photocathode plate, temperature sensing module and central control system; The laser source is used to provide the initial laser beam; The input terminal of the wavelength selection switch module is connected to the laser source and is used to receive the initial laser and split and modulate it into multiple output lasers with different wavelengths and intensities that can be independently controlled. The input end of the output fiber array is connected to the output end of the wavelength selection switch module, and the output end of the output fiber array is arranged opposite to the photocathode plate to guide multiple output laser beams and form a dot matrix of light spots that irradiate different positions on the photocathode plate. The temperature sensing module is a thin-film structure and is disposed on the light-receiving surface of the photocathode plate, used to monitor the temperature of each light spot irradiation point and irradiation area in real time. The central control system is connected to the wavelength selection switch module and the temperature sensing module respectively, and is used to dynamically adjust the wavelength selection switch module to allocate wavelength and light intensity to each output laser according to the temperature data fed back by the temperature sensing module.

2. The system according to claim 1, characterized in that, The central control system pre-stores the temperature-threshold energy correlation data of the photocathode plate, and the central control system is configured to: Receive real-time temperature data from the temperature sensing module; Based on the temperature-threshold energy correlation data and real-time temperature data, the target photon energy required at each position of the photocathode plate is calculated. The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

3. The system according to claim 1, characterized in that, The thin film structure is a thin film thermal sensor array deposited on the light-receiving surface of the photocathode plate, wherein the photon reaction cross section of the material of the thin film thermal sensor array is lower than a preset threshold.

4. The system according to claim 2, characterized in that, It also includes a temperature data preprocessing unit connected to the temperature sensing module, which is used to preprocess the temperature analog signal collected by the temperature sensing module and feed it back to the central control system in a preset data format. The central control system generates a control command for the wavelength selection switch module based on the received data. The preset data format includes a two-dimensional array or a visual heatmap. The two-dimensional array is used for internal system processing and comparison with a preset threshold. The visual heatmap is used to provide users with an intuitive display of temperature distribution.

5. The system according to claim 4, characterized in that, The central control system generates control commands for the wavelength selection switch module based on the received data, including over-threshold control commands and threshold energy adaptation control commands. The over-threshold control command includes: when the temperature at a certain monitoring point exceeds the preset safety threshold corresponding to the material at that point, controlling the wavelength selection switch module to reduce the light intensity of the output laser irradiating that point or adjust it to a higher wavelength to suppress the temperature rise at that point; The threshold energy adaptation and control command includes: when the temperature at a certain monitoring point does not exceed the threshold but fluctuates, dynamically adjusting the laser wavelength irradiating the point according to the temperature-threshold energy correlation data, so that the photon energy matches the real-time threshold energy, thereby maintaining the optimal photoelectric emission efficiency at that point.

6. The system according to claim 1, characterized in that, The wavelength selective switch module adopts a layout with the incident and output ends on opposite sides. Internally, along the optical path, the module sequentially includes an incident fiber, a first electrically controlled grating, a second electrically controlled grating, an electrically controlled micromirror array, and the input end of the output fiber array. The first electronically controlled grating is used to perform angular separation of the incident laser in space; The second electronically controlled grating is used to converge or mix the separated light beams; Each micromirror unit in the electrically controlled micromirror array is independently controllable and is used to reflect the light beam processed by the second electrically controlled grating to the designated input port of the output fiber array.

7. The system according to claim 6, characterized in that, The first electronically controlled grating is an electronically controlled scattering grating, and the second electronically controlled grating is an electronically controlled focusing grating.

8. A method for controlling a WSS-based light source-photocathode system, applied to the WSS-based light source-photocathode system as described in any one of claims 1-7, characterized in that, include: The temperature sensing module acquires the temperature data of each spot irradiated by the photocathode plate in real time, and converts the temperature data into a preset format before feeding it back to the central control system. Based on the temperature data and pre-stored temperature-threshold energy correlation data, the target photon energy required to irradiate each location is determined. The wavelength selection switch module is adjusted according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy.

9. The method according to claim 8, characterized in that, The step of adjusting the wavelength selection switch module according to the target photon energy required at each position, so that the laser photon energy output to each position of the photocathode plate matches its corresponding target photon energy, includes: The temperature at each location is compared with its preset safety threshold. If the temperature at any location exceeds its preset safety threshold, the target laser parameters at the corresponding location will be set to cooling parameters with the primary goal of reducing the heat load in that area. If the temperature at all points is below the safe threshold, the target laser parameters at the corresponding locations are set to efficiency optimization parameters that match the laser photon energy with the target photon energy.

10. The method according to claim 8, characterized in that, The pre-stored temperature-threshold energy correlation data is obtained through the following steps: Photoelectric response tests were conducted at different temperatures and locations. The threshold energy spatial distribution of the photocathode plate and its relationship with temperature are calibrated and stored.

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