Polychromators, plasma diagnostic systems and fusion reaction systems

Abstract

The present application provides a polychromator, a plasma diagnostic system and a fusion reaction system; the polychromator includes a first lens barrel assembly, which includes a filter with a wedge-shaped structure; the angle between the normal direction of the incident surface of the filter and the direction of the incident light is greater than the angle between the normal direction of the exit surface of the filter and the direction of the transmitted light; the incident surface and the exit surface of the filter are coated with a filter film, and the filter film selectively transmits light of a specific wavelength in the incident light; the detector converts the light of a specific wavelength into an electrical signal. The phase matching of the optical path is optimized by the wedge-shaped filter structure, the blue shift of the central wavelength and the broadening of the bandwidth are significantly suppressed, the problem of light crosstalk in the multi-level splitting optical path is effectively solved, and the diagnostic accuracy is improved.

Description

Technical Field

[0001] The present application relates to the field of nuclear fusion technology, and in particular to a polychromator, a plasma diagnostic system and a fusion reaction system. Background Art

[0002] With the in-depth development of plasma physics research, plasma diagnostic systems have been widely used as an important plasma diagnostic measurement tool. For example, based on the scattering phenomenon of electromagnetic waves by electrons in plasma, by measuring the frequency and intensity changes of scattered light, key parameters such as the plasma electron temperature Te and electron density ne can be inferred. This diagnostic method plays an important role in detecting the state of plasma in nuclear fusion reaction devices.

[0003] At present, in the polychromator of the plasma diagnostic system, the light path passes through the selective transmission of the filter in the lens barrel assembly and is collected by the detector in the lens barrel assembly. However, since multiple lens barrel assemblies need to be set in the polychromator to cover the scattered spectrum analysis of different wavelength ranges, due to the limitation of spatial layout, stray light suppression and reflection light path considerations, the angle of the incident light entering the lens barrel assembly is often not 0° (the angle between the incident light direction and the normal direction of the incident surface of the filter), and it cannot meet the specific phase matching conditions of the lens barrel assembly, resulting in the central wavelength blue shift and bandwidth widening of the light of the specific wavelength transmitted through the filter, which leads to a significant wavelength error between the light of the specific wavelength collected by the detector in the lens barrel assembly and the pre-set selective transmission wavelength, resulting in cross-light problems between the various levels of split light paths composed of multiple lens barrel assemblies, resulting in insufficient accuracy of the diagnostic results of the plasma diagnostic system. Summary of the invention

[0004] The present application provides a polychromator, a plasma diagnostic system and a fusion reaction system, which optimize the optical path phase matching through a wedge-shaped filter structure, significantly suppress the blue shift of the central wavelength and the broadening of the bandwidth, effectively solve the problem of light crosstalk in the multi-level splitting optical path, and improve the diagnostic accuracy.

[0005] According to one aspect of an embodiment of the present application, a polychromator is provided, the polychromator comprising a first lens barrel assembly, the first lens barrel assembly comprising a filter and a detector in a wedge-shaped structure;

[0006] The angle between the normal direction of the incident surface of the filter and the direction of the incident light is greater than the angle between the normal direction of the exit surface of the filter and the direction of the transmitted light;

[0007] The incident and exit surfaces of the filter are coated with filter films, which selectively transmit light of a specific wavelength in the incident light;

[0008] Detectors convert light of a specific wavelength into an electrical signal.

[0009] According to another aspect of an embodiment of the present application, a plasma diagnostic system is provided, comprising the above-mentioned polychromator.

[0010] According to another aspect of the embodiments of the present application, a fusion reaction system is provided, and the fusion reaction system includes a nuclear fusion reaction device and the above-mentioned plasma diagnostic system.

[0011] In the polychromator provided by the present application, the incident surface and the exit surface of the wedge-shaped filter are asymmetric, and the target wavelength is preliminarily screened by using the oblique incidence transmission characteristics on the first surface, and the out-of-range spectrum is accurately cut off by a smaller angle incidence condition on the second surface, thereby realizing dynamic compensation for phase mismatch, avoiding the blue shift of the central wavelength and the widening of the bandwidth, and reducing the wavelength error between the light of a specific wavelength collected by the detector in the lens barrel assembly and the pre-set selective transmission wavelength. At the same time, the geometric characteristics of the wedge-shaped structure combined with the double-surface filtering cause the transmission light axis of each lens barrel assembly to form a natural deflection in space, thereby suppressing the cross-talk problem between the various levels of split light paths formed by multiple lens barrel assemblies, and improving the accuracy of the diagnostic results of the plasma diagnostic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a structural schematic diagram of a polychromator provided in one embodiment of the present application;

[0013] Figure 2 is a schematic diagram of a filter in a polychromator provided in an embodiment of the present application;

[0014] Figure 3 It is a schematic diagram of the internal structure of a three-port optical circulator in a polychromator provided in one embodiment of the present application;

[0015] Figure 4 This is a schematic diagram of the optical path of a polychromator provided in one embodiment of the present application;

[0016] Figure 5 is a structural diagram of a polychromator provided in one embodiment of the present application;

[0017] Figure 6 is a structural schematic diagram of a plasma diagnostic system provided by an embodiment of the present application;

[0018] Figure 7 It is a structural schematic diagram of a fusion reaction system provided in one embodiment of the present application;

[0019] Reference numerals

[0020] Polychromator-100; first lens barrel assembly-110; light path box-120; second lens barrel assembly-130; optical fiber-140; optical fiber assembly-150; filter-1110; detector-1120; relay lens-1130; imaging lens-1140; light circulator-1310; light devourer-1320; collimator lens assembly-1510; plasma diagnostic system-10; nuclear fusion reaction device-20; fusion reaction system-30. DETAILED DESCRIPTION

[0021] Many specific details are described in the following description to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present application, so the present application is not limited by the specific implementation disclosed below.

[0022] The terms used in one or more embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of the present application. The singular forms of "one", "said" and "the" used in one or more embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of the present application refers to and includes any or all possible combinations of one or more associated listed items. The term "at least one" in one or more embodiments of the present application refers to "one or more", and "multiple" refers to "two or more". The term "including" is an open description and should be understood as "including but not limited to", and may include other content on the basis of the content described.

[0023] It should be understood that, although the terms "first", "second", etc. may be used to describe various information in one or more embodiments of the present application, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of the present application, "first" may also be referred to as "second", and similarly, "second" may also be referred to as "first". Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0024] First, the terms involved in one or more embodiments of the present application are explained.

[0025] Plasma: A thermodynamic state of matter, often referred to as the fourth state of matter. It consists of a large number of free electrons and ionized atoms, and is generally electrically neutral but highly conductive and responsive to electromagnetic fields. At extremely high temperatures, the atoms in a gas are ionized into free electrons and positive ions, a state commonly seen in the interiors of stars, in lightning, and under certain types of laboratory conditions.

[0026] Thomson scattering: A phenomenon based on the scattering of electromagnetic waves by electrons in plasma, a process in which electromagnetic wave photons collide elastically with free electrons. In this process, the energy of the photons is not absorbed but changes its direction of movement.

[0027] Thomson scattering diagnostic system: A plasma diagnostic system that uses the principle of Thomson scattering to measure plasma parameters such as temperature and density. The system usually includes one or more lasers to generate high-energy beams that enter the plasma and scatter with the free electrons in it. By detecting the direction and frequency changes of the scattered light, key parameters such as the electron temperature Te and electron density ne inside the plasma can be inferred.

[0028] Polychromator: A spectroscopic instrument that can decompose complex light into monochromatic light and accurately measure the intensity of each wavelength. In nuclear fusion research, polychromators are used to collect and analyze the spectrum of light emitted from plasma.

[0029] Avalanche Photodiode (APD): A highly sensitive photodetector that can effectively detect photons when the light signal is extremely weak. Avalanche photodiodes enhance the light signal by amplifying the photocurrent generated by the incident photons using the avalanche multiplication effect. During the avalanche multiplication process, photogenerated carriers obtain sufficient energy in the high electric field region, and then collide and ionize other atoms, generating more electron-hole pairs, forming an "avalanche" amplification of the current. Due to their high gain, fast response, and excellent signal-to-noise ratio, avalanche photodiodes are widely used in situations where weak light signals need to be accurately measured, such as laser ranging, fiber-optic communications, and plasma diagnostic systems in plasma physics research. Compared with ordinary photodiodes, avalanche photodiodes can operate at lower light intensities and provide higher sensitivity and more accurate measurement results.

[0030] Nuclear fusion: Nuclear fusion refers to the process in which the nuclei of light elements combine to form heavier elements under high temperature and high pressure conditions, accompanied by the release of a large amount of energy. Unlike fission, fusion does not produce long-lasting radioactive waste, and the fuel source is extensive (such as deuterium and tritium isotopes of hydrogen in seawater). Nuclear fusion is the source of energy for the sun and other stars to emit light and heat, and is also one of the clean energy sources pursued by humans.

[0031] Nuclear fusion reaction device: A device for realizing and controlling nuclear fusion reactions, which aggregates lighter element particles (such as hydrogen isotopes deuterium and tritium) into heavier element particles under high temperature and high pressure conditions, and releases a large amount of energy. Nuclear fusion reaction devices usually include the following key components: 1. Nuclear fusion vacuum reaction chamber: Contains and maintains the plasma state under high temperature and high pressure, making it suitable for nuclear fusion reactions. 2. Heating system: Heats lighter element particles, such as radio frequency heating, neutral beam injection, etc. 3. Magnetic confinement device: Uses a strong magnetic field to limit plasma to prevent it from directly contacting the inner wall of the vacuum reaction chamber, such as tokamak devices and stellarator devices. 4. Diagnostic system: Including plasma diagnostic systems, etc., real-time monitoring of plasma state parameters, such as temperature, density and stability, so as to provide a basis for adjusting experimental parameters and ensure the optimization of reaction conditions.

[0032] Tokamak: Tokamak is a magnetic confinement device specially designed for controlled nuclear fusion experiments. It uses a strong toroidal or spherical magnetic field and a spiral twisted coil to confine high-temperature plasma and prevent it from directly contacting the inner wall of the vacuum reaction chamber. The strong magnetic field generated inside the Tokamak can effectively keep the plasma in a stable orbit.

[0033] Stellarator device: Stellarator is a magnetic confinement device different from tokamak. It generates a twisted three-dimensional magnetic field structure through a complex coil configuration to stabilize and confine plasma. Compared with tokamak, stellarator does not require electric current to maintain the stability of plasma, which reduces the problems caused by current fluctuations.

[0034] Central wavelength blue shift: When light enters the filter at a non-perpendicular angle, the peak wavelength of the transmission spectrum shifts toward the short-wave direction. Specifically, the transmission center wavelength is determined by the phase matching condition, see formula 1:

[0035] Formula 1

[0036] in, is the interference level, is the theoretical transmission center wavelength, is the refractive index of the filter material, is the physical thickness of the filter, is the propagation angle of light inside the filter (the angle between the light and the normal line of the filter surface). At the time of incidence ( 0°), according to Snell's law , the effective optical path difference is reduced to .

[0037] With the incident angle The increase of decreases, resulting in a transmission wavelength decreases (shifts toward the short-wave direction), and the blue shift can be quantified as , see formula 2:

[0038] Formula 2

[0039] in, is the central wavelength at vertical incidence, is the theoretical transmission center wavelength, is the propagation angle of light inside the filter.

[0040] Bandwidth broadening: The phenomenon that the half-maximum bandwidth (Full Width at Half Maximum, FWHM) of the transmission spectrum widens as the incident angle increases.

[0041] The bandwidth of a Fabry-Perot filter is determined by Equation 3:

[0042] Formula 3

[0043] in, is the half-height bandwidth of the transmission spectrum of the Fabry-Perot filter, is the theoretical transmission center wavelength, is the refractive index of the filter material, is the physical thickness of the filter, is the reflectivity of the filter surface.

[0044] At oblique incidence, at oblique incidence, equivalent optical thickness , resulting in the actual bandwidth correction as shown in Formula 4:

[0045] Formula 4

[0046] in, is the correction value of the half-height bandwidth of the transmission spectrum of the Fabry-Perot filter, is the theoretical half-height bandwidth of the transmission spectrum of the Fabry-Perot filter, is the propagation angle of light inside the filter.

[0047] With the incident angle The increase of Reduced, equivalent optical thickness decreased, interference order The effective value of is reduced and the sharpness of the transmission peak decreases, resulting in a broadening of the bandwidth.

[0048] Crosstalk: The phenomenon in which the detector receives signals in non-target bands due to spectral overlap between adjacent split light paths.

[0049] Set up The pre-set selective transmission wavelength of each lens tube assembly is , the actual transmission wavelength becomes due to blue shift and broadening . The adjacent level splitting optical path Crosstalk occurs between the j-th lens barrel assembly and the j-th lens barrel assembly, as shown in Formula 5:

[0050] Formula 5

[0051] The present application provides a polychromator, a plasma diagnostic system and a fusion reaction system, which optimize the optical path phase matching through a wedge-shaped filter structure, significantly suppress the blue shift of the central wavelength and the broadening of the bandwidth, effectively solve the problem of light crosstalk in the multi-level splitting optical path, and improve the diagnostic accuracy.

[0052] Figure 1 1 is a schematic structural diagram of a polychromator provided in an embodiment of the present application. The polychromator 100 includes a first lens barrel assembly 110. The first lens barrel assembly 110 includes a wedge-shaped filter 1110 and a detector 1120.

[0053] The angle between the normal direction of the incident surface of the filter 1110 and the direction of the incident light is greater than the angle between the normal direction of the exit surface of the filter 1110 and the direction of the transmitted light;

[0054] The incident surface and the output surface of the filter 1110 are coated with filter films, and the filter films selectively transmit light of a specific wavelength in the incident light;

[0055] The detector 1120 converts light of a specific wavelength into an electrical signal.

[0056] The polychromator 100 is a spectroscopic analysis instrument that can decompose complex light into monochromatic light and accurately measure the light intensity of each wavelength.

[0057] The first lens barrel assembly 110 is a component for light beam transmission and light splitting in the polychromator 100. The first lens barrel assembly 110 receives a light beam from the plasma, decomposes it into monochromatic lights of different wavelengths through internal optical elements, transmits (selectively passes) monochromatic lights of specific wavelengths, and converts the monochromatic lights into electrical signals for precise measurement. In one embodiment, there are multiple first lens barrel assemblies 110, corresponding to monochromatic lights of multiple specific wavelengths, and each first lens barrel assembly 110 corresponds to a spectroscopic optical path (spectroscopic optical path). For example, if 6 levels of spectroscopic optical paths need to be collected, the polychromator 100 includes 6 first lens barrel assemblies 110, and the transmission wavelength range of the first spectroscopic optical path is 950nm±37nm, the transmission wavelength range of the second spectroscopic optical path is 1000nm±23nm, the transmission wavelength range of the third spectroscopic optical path is 1030nm±12nm, the transmission wavelength range of the fourth spectroscopic optical path is 1048nm±8nm, the transmission wavelength range of the fifth spectroscopic optical path is 1058nm±3nm, and the transmission wavelength range of the sixth spectroscopic optical path is 1078nm±12nm.

[0058] The wedge-shaped filter 1110 is an optical filter with an asymmetric geometric shape, and its incident surface and the exit surface are at a wedge-shaped angle. The incident surface and the exit surface of the filter 1110 have different normal directions, and the incident surface angle (α) is greater than the exit surface angle (β). The optical path difference is pre-compensated by the incident surface angle (α), combined with the adjustment of the exit surface angle (β), to achieve dynamic correction of the optical path. For example, if the incident surface angle α = 2°-8°, which is equal to the angle between the incident light direction and the horizontal direction, and the exit surface angle β = 0°, the light propagation path in the filter 1110 is refracted and corrected, effectively reducing phase mismatch.

[0059] The incident surface of the filter 1110 is the surface of the filter 1110 that receives the incident light, the normal direction of which forms an angle with the direction of the incident light, and the surface is coated with a gradient filter film to achieve preliminary wavelength screening.

[0060] The output surface of the filter 1110 is the surface through which the transmitted light of the filter 1110 is output, and its normal direction forms an angle with the direction of the transmitted light, which is usually close to vertical (β≈0°), and the surface is coated with a gradient filter film to achieve secondary wavelength screening.

[0061] The filter film is a multilayer optical film coated on the surface of the filter 1110, which selectively transmits light of a specific wavelength through the interference effect. The gradient film thickness design is used to make different positions correspond to different transmission center wavelengths, adapting to the optical path distribution of oblique incident light. The high reflectivity film layer reflects light of non-target wavelengths, so that the lens barrel components of other split light paths can collect it. In one embodiment, the filter film reflects light of non-target wavelengths and combines with the light devourer 1320 to eliminate stray light.

[0062] The detector 1120 is a component that receives light of a specific wavelength passing through the exit slit. The selection of the detector 1120 depends on the specific application requirements, such as sensitivity, response speed, and spectral range. The detector 1120 measures the intensity of light passing through a specific wavelength, converts the optical signal into an electrical signal, and then amplifies and processes it through an electronic circuit.

[0063] In one embodiment, detector 1120 includes a photodiode and an amplifier circuit.

[0064] Among them, photodiodes are semiconductor devices that convert light signals into electrical signals. Photodiodes usually operate under reverse bias voltage conditions and generate current when exposed to light. The working principle of photodiodes is based on the internal photoelectric effect, that is, when a photon with sufficient energy hits the diode, a pair of electron-hole pairs is generated. These carriers are separated by the built-in electric field in the depletion region to form a photocurrent. For example, an avalanche photodiode that uses nanosecond pulse light signal detection.

[0065] The amplifier circuit is an electronic circuit that increases the amplitude or power of an electrical signal, thereby enhancing a weak electrical signal. The amplifier circuit includes at least one operational amplifier. For example, a gain amplifier circuit using a transimpedance amplifier (TIA) architecture includes an operational amplifier (OPA) with a gain-bandwidth product of 1.6 GHz, an input noise voltage of 4.8 nV / √Hz, and a transimpedance gain setting of 10 kΩ-1 MΩ, which can convert the nA-level photocurrent output by the photodiode into a multi-voltage signal.

[0066] In one embodiment, Figure 2 FIG. 1 shows a schematic diagram of a filter in a polychromator provided in an embodiment of the present application, such as Figure 2 As shown:

[0067] When the light is on the incident surface of the wedge-shaped filter 1110, the angle α between the normal direction of the incident surface and the direction of the incident light is greater than 0°, and refraction and reflection will occur, forming transmitted light generated after entering the filter 1110 and reflected light that has not entered the filter 1110. The central wavelength of the transmitted light is blue-shifted, and the bandwidth becomes wider. The wavelength range of the transmitted light is greater than the wavelength range pre-set for the first lens barrel assembly 110. The transmitted light will then reach the exit surface of the filter 1110, and the angle β between the normal direction of the exit surface and the direction of the transmitted light is close to 0°, further filtering out the light outside the wavelength range pre-set for the first lens barrel assembly 110. The reflected light on the exit surface will return along the original path in the opposite direction of the incident direction.

[0068] In the embodiment of the present application, the incident surface and the exit surface of the wedge-shaped filter 1110 are asymmetric, and the target wavelength is preliminarily screened by using the oblique incidence transmission characteristics on the first surface, and the out-of-range spectrum is accurately cut off by a smaller angle incidence condition on the second surface, thereby realizing dynamic compensation for phase mismatch, avoiding the blue shift of the central wavelength and the widening of the bandwidth, and reducing the wavelength error between the light of a specific wavelength collected by the detector 1120 in the barrel assembly and the preset selective transmission wavelength. At the same time, the geometric characteristics of the wedge-shaped structure are combined with double-surface filtering, so that the transmission light axis of each barrel assembly forms a natural deflection in space, suppressing the cross-talk problem between the various levels of split light paths formed by multiple barrel assemblies, and improving the accuracy of the diagnosis result of the plasma diagnostic system 10.

[0069] In one embodiment of the present application, the first lens barrel assembly 110 further includes a relay lens 1130 , and the relay lens 1130 is a convex lens or a semi-convex lens;

[0070] The incident light is incident into the first lens barrel assembly 110 through the relay lens 1130;

[0071] The reflected light is emitted from the first lens barrel assembly 110 through the relay lens 1130 . The reflected light is the light reflected from the incident surface of the filter 1110 .

[0072] The relay lens 1130 is an optical element with an optical path adjustment function, usually a convex lens or a semi-convex lens, usually made of fused quartz or glass, and coated with a wide-band anti-reflection film on the surface. In one embodiment, the focal length is between 180mm and 600mm. Since the light beam cannot always maintain its collimation and phase consistency during propagation, the light spot diverges or the wavefront is distorted, causing the phase matching condition of the subsequent filter 1110 to deviate from the design value and the signal-to-noise ratio of the signal received by the detector 1120 to decrease. For example, in a system without a relay lens 1130, the spot diameter of the incident light may expand to more than 3mm after long-distance transmission, while the effective aperture of the filter 1110 is only 5mm. At this time, the incident angle deviation of the edge light exceeds ±2°, which significantly aggravates the blue shift effect (as shown in Formula 2) and bandwidth broadening (as shown in Formula 4).

[0073] The incident light is a complex light beam scattered from the plasma and entering the polychromator 100. When the incident light passes through the relay lens 1130, the convergence characteristics of the lens can collimate and compress the light beam, and control the divergence angle within a certain range to form a light beam. For example, when a convex lens with a focal length of 300 mm is used, the incident light beam with an original divergence angle of ±3° can be compressed to ±0.4°, so that the light enters the incident surface of the filter 1110 at a closer design incident angle (such as α=15°±0.3°).

[0074] The reflected light is the light of non-specific wavelength components reflected by the incident light on the incident surface of the filter 1110. The reflected light can be adjusted by the coating reflectivity of the filter film on the incident surface. The reflected light is refocused by the relay lens 1130 and then returns to the optical path box 120 of the polychromator 100, as shown in FIG. Figure 2 shown.

[0075] In the embodiment of the present application, the collimation and phase consistency of the incident light are optimized by introducing the relay lens 1130, and the original divergence angle can be significantly reduced by using a convex lens or a semi-convex lens with an appropriate focal length, ensuring that the light accurately enters the filter 1110 at an angle close to the design value, thereby greatly reducing the central wavelength blue shift and bandwidth broadening phenomenon, and improving the measurement accuracy and stability of the system. At the same time, the reflected light is effectively controlled, avoiding unnecessary stray light interference, and further improving the accuracy of the diagnosis result.

[0076] In one embodiment of the present application, the first lens barrel assembly 110 further includes an imaging lens 1140, which is located between the filter 1110 and the detector 1120, and the imaging lens 1140 is a convex lens or a semi-convex lens, and the detector 1120 is located at the focus of the imaging lens 1140;

[0077] The incident light is transmitted through the imaging lens 1140 and enters the detector 1120 .

[0078] The imaging lens 1140 is a short focal length optical element, usually a convex lens or a semi-convex lens, usually made of fused quartz or glass, and coated with a wide-band anti-reflection film on the surface. In one embodiment, the focal length is between 10mm and 40mm. The optical axis of the imaging lens 1140 is coaxial with the incident light. For example, the angle between the incident light direction and the horizontal direction is 2°-8°, and the optical axis of the imaging lens 1140 is also installed at the same angle to ensure that the angle between the optical axis of the imaging lens 1140 and the horizontal direction is also 2°-8°, and the optical path of the transmitted light is symmetrical. Through a precise mechanical positioning structure (such as a lens flange and a bolt structure), the distance between the lens center of the imaging lens 1140 and the exit surface of the filter 1110 can be controlled within a very small range (for example, ±0.05mm), achieving micron-level accuracy in optical path alignment.

[0079] The detector 1120 is located at the focus of the imaging lens 1140. One feasible method is that the light-receiving surface of the photodiode in the detector 1120 is located at the focus of the imaging lens 1140. For example, when a convex lens with a focal length of f=25 mm is used, the distance between the lens and the light-receiving surface of the avalanche photodiode is designed to be 25.0±0.1 mm. At this time, the diameter of the scattered light spot passing through the filter 1110 can be compressed to below the micron level, so that the light power density is increased to several times (for example, thousands of times) the initial value. This design significantly enhances the detection efficiency of the detector 1120, especially for the weak light intensity commonly found in the Thomson scattering signal, and can improve the signal-to-noise ratio.

[0080] In the embodiment of the present application, by introducing an imaging lens 1140 between the filter 1110 and the detector 1120, precise focusing of the scattered light passing through the filter 1110 is achieved, the spot diameter is compressed, and the optical power density and detection efficiency are greatly improved, which not only improves the signal-to-noise ratio, but also enhances the detection sensitivity and measurement accuracy.

[0081] In one embodiment of the present application, the polychromator 100 further includes an optical path box 120 , and the first lens barrel assembly 110 is multiple;

[0082] A plurality of first lens barrel assemblies 110 are cascaded and mounted on the inner wall of the optical path box 120, and adjacent first lens barrel assemblies 110 are connected via a reflection optical path to form a multi-level splitting optical path;

[0083] The incident surface of the filter 1110 in any first lens barrel assembly 110 is coated with a filter film of target thickness, and the filter film of target thickness selectively transmits light of a wavelength corresponding to the target thickness in the incident light.

[0084] The optical path box 120 is a closed space structure in the polychromator 100. The optical path box 120 accommodates the optical path and installs and fixes various components of the polychromator 100. The optical path box 120 is generally a sealed box body made of metal, plastic or composite materials. The inner wall of the optical path box 120 is the boundary surface of the internal space of the optical path box 120, and the installation positions of the first lens barrel assembly 110 and other components are pre-set on the inner wall.

[0085] In one embodiment, the first lens barrel assembly 110 is mounted on the inner wall of the optical path box 120 via a lens flange, wherein an angle exists between the axis of the first lens barrel assembly 110 and the inner wall of the optical path box 120, and the angle is adjusted by screwing a bolt passing through the lens flange.

[0086] At least one bolt hole is provided at the installation position of the first lens barrel assembly 110, so that the lens flange can be fixed to the inner wall of the optical path box 120 by bolts. The inner wall is usually made of a metal plate treated with a matte coating to absorb stray light.

[0087] The lens flange is a mechanical interface of an annular structure, and the first lens barrel assembly 110 is mounted on the inner wall of the optical path box 120. The lens flange is provided with at least one bolt through hole, so that the bolt can pass through. The lens of the first lens barrel assembly 110 is located between the lens flange and the inner wall, and the inner ring diameter of the lens flange is smaller than the diameter of the lens of the first lens barrel assembly 110, so as to ensure that the lens is fixed in a predetermined position and does not move.

[0088] The bolt is a mechanical fastener, and the bolt passes through the lens flange to install the first lens barrel assembly 110 on the inner wall of the optical path box 120, and the angle is adjusted by rotation. The bolt may include a straight-through bolt for installation, and a rotating bolt for installation and adjustment of the angle, or may only include a rotating bolt for installation and adjustment of the angle, which is not limited here.

[0089] The angle can be adjusted by screwing the bolts passing through the lens flange, so that the light beam enters the first lens barrel assembly 110 at the expected incident angle, and is reflected back to the light path box 120 at the corresponding reflection angle, and is transmitted by other first lens barrel assemblies 110, completing the collection of monochromatic light of different wavelengths one by one.

[0090] A plurality of first lens barrel assemblies 110 are cascaded and installed on the inner wall of the optical path box 120, and adjacent first lens barrel assemblies 110 are connected by a reflection optical path to form a multi-level splitting optical path. A feasible method is: a plurality of first lens barrel assemblies 110 are cascaded and installed on the inner wall of the optical path box 120 in increasing order of wavelength. For example, six first lens barrel assemblies 110 are cascaded and installed in sequence in increasing order of wavelength (950nm-1078nm). The axis of each lens barrel assembly is inclined at an angle of 2°-8° to the horizontal direction, forming a "Z"-shaped optical path topology. The transmission wavelength range of the first split optical path is 950nm±37nm, the transmission wavelength range of the second split optical path is 1000nm±23nm, the transmission wavelength range of the third split optical path is 1030nm±12nm, the transmission wavelength range of the fourth split optical path is 1048nm±8nm, the transmission wavelength range of the fifth split optical path is 1058nm±3nm, and the transmission wavelength range of the sixth split optical path is 1078nm±12nm. The distribution from short wavelength to long wavelength avoids the problem of the long wavelength split optical path receiving the optical signal of the short wavelength split optical path due to the incident light angle greater than 0° on the surface of the filter 1110, that is, the crosstalk problem between different split optical paths.

[0091] On this basis, the filter 1110 in the first lens barrel assembly 110 corresponding to the last-stage split light path is in a pancake shape.

[0092] The incident surface of the filter 1110 in any first lens barrel assembly 110 is coated with a filter film of target thickness, and the filter film of target thickness selectively transmits light of a wavelength corresponding to the target thickness in the incident light. The relationship between the two is shown in Formula 6:

[0093] Formula 6

[0094] Where x is the coordinate along the length direction of the wedge surface. The incident light experiences equivalent vertical incidence at different positions of the filter 1110, and the central wavelength of the transmitted light is Locked at set value.

[0095] Exemplarily, the collimated light beam is incident on the incident surface of the wedge-shaped filter 1110 (the surface is coated with a gradient filter film, and the film thickness gradient corresponds to λ=970nm) at a designed incident angle α=5°, wherein the light component that meets the central wavelength λ=950nm passes through the filter 1110, and the light of other wavelengths is reflected to the second-stage split light path channel. The transmitted 950nm light is converted into a current signal by the avalanche photodiode. The light beam reflected to the second stage is incident on the incident surface of the second wedge-shaped filter 1110 (the film thickness gradient corresponds to λ=1000nm) at the same wedge angle, wherein the light component that meets the central wavelength λ=1000nm passes through the filter 1110, and the light of other wavelengths is reflected to the third-stage split light path channel. The transmitted 1000nm light is converted into a current signal by the avalanche photodiode. This process is repeated until the fifth stage. When the incident surface of the wedge-shaped filter 1110 (film thickness gradient corresponds to λ=1058nm), the reflected light enters the sixth stage light splitting path. Because the circular filter 1110 is used (the normal direction of the incident surface coincides with the optical axis, β=0°), the transmitted 1078nm light does not blue shift, and the transmitted 1078nm light is converted into a current signal by the avalanche photodiode. The film thickness error of the gradient filter film on the surface of the wedge-shaped filter 1110 is less than ±2nm, which can be achieved by ion beam sputtering coating process.

[0096] In the embodiment of the present application, a plurality of first lens barrel assemblies 110 are installed in cascade in the optical path box 120 to form a multi-stage light splitting optical path, thereby effectively avoiding the problem of light crosstalk between channels of different wavelengths.

[0097] In one embodiment of the present application, the polychromator 100 further includes a second lens barrel assembly 130, which is mounted on the inner wall of the optical path box 120, and the second lens barrel assembly 130 is connected to the first lens barrel assembly 110 via an incident light path, and the second lens barrel assembly 130 includes an optical circulator 1310;

[0098] The optical circulator 1310 includes at least two optical ports. The incident light path is incident on the first port, and the incident light path is incident on the optical path box 120 from the second port.

[0099] The second lens barrel assembly 130 is a component in the polychromator 100 that receives and guides the light beam into the optical path box 120. The second lens barrel assembly 130 is not only used to introduce external light into the polychromator 100, but also controls the directionality and isolation of the optical signal through the optical circulator 1310.

[0100] The optical circulator 1310 is a non-reciprocal optical device that allows optical signals to be transmitted from one port to the next port in a specific order, but prevents reverse transmission. The optical circulator 1310 uses magneto-optical materials and polarization control technology inside, so that the optical signal input to any port can only be output in a predetermined direction sequence. The optical circulator 1310 includes but is not limited to: a three-port optical circulator, a four-port optical circulator, etc. For example, in a three-port optical circulator, light entering from the first port will only be output from the second port; and light entering from the second port will only be output from the third port. This feature is very useful for preventing reverse reflection, protecting the light source, and improving the stability of the system.

[0101] The first port is an input / output optical path interface of the optical circulator 1310 for receiving an optical signal from an external device. The second port is another input / output optical path interface of the optical circulator 1310 for outputting the optical signal received from the first port to the optical path box 120.

[0102] In one embodiment, the second lens barrel assembly 130 is mounted on the inner wall of the optical path box 120 via a lens flange, wherein an angle exists between the axis of the second lens barrel assembly 130 and the inner wall of the optical path box 120, and the angle is adjusted by screwing a bolt passing through the lens flange.

[0103] At least one bolt hole is provided at the installation position of the second lens barrel assembly 130, so that the lens flange can be fixed to the inner wall of the optical path box 120 by bolts. The inner wall is usually made of a metal plate treated with a matte coating to absorb stray light.

[0104] The lens flange is a mechanical interface of an annular structure, and the second lens barrel assembly 130 is mounted on the inner wall of the optical path box 120. The lens flange is provided with at least one bolt through hole, so that the bolt can pass through. The lens of the second lens barrel assembly 130 is located between the lens flange and the inner wall, and the inner ring diameter of the lens flange is smaller than the diameter of the lens of the second lens barrel assembly 130, so as to ensure that the lens is fixed in a predetermined position and does not move.

[0105] The bolt is a mechanical fastener, and the bolt passes through the lens flange to install the second lens barrel assembly 130 on the inner wall of the optical path box 120, and the angle is adjusted by rotation. The bolt may include a straight-through bolt for installation, and a rotating bolt for installation and adjustment of the angle, or may only include a rotating bolt for installation and adjustment of the angle, which is not limited here.

[0106] The angle can be adjusted by screwing the bolts passing through the lens flange so that the light beam enters the optical path box 120 at a desired incident angle.

[0107] In the embodiment of the present application, by introducing the second lens barrel assembly 130 and the optical circulator 1310 into the polychromator 100, efficient directional transmission and isolation of optical signals are achieved, the influence of stray light is prevented, and the stability and measurement accuracy are enhanced.

[0108] In one embodiment of the present application, the optical circulator 1310 includes two polarization beam splitters, two reflectors, a Faraday rotator and a half-wave plate;

[0109] The forward optical path of the optical circulator 1310 includes:

[0110] The incident light incident from the first port is incident on the first polarization beam splitter, and the incident light is separated into the first polarization light and the second polarization light;

[0111] The first polarized light is incident on the first reflector and is reflected. The reflected first polarized light is transmitted through the Faraday rotator and rotated clockwise with the first polarized light direction as the axis. The rotated first polarized light is transmitted through the half-wave plate and rotated clockwise with the first polarized light direction as the axis.

[0112] The second polarized light passes through the Faraday rotator and rotates clockwise with the second polarized light direction as the axis. The rotated second polarized light passes through the half-wave plate and rotates clockwise with the second polarized light direction as the axis. The rotated second polarized light is reflected on the second reflector.

[0113] The first polarized light and the second polarized light are incident on the second polarization beam splitter, and are combined into incident light and emitted from the second port.

[0114] A polarization beam splitter is an optical element that selectively splits light based on polarization state. It separates the incident light into two orthogonal linear polarized lights according to the polarization state through a multilayer dielectric film or a birefringent crystal structure. The difference in reflection and transmission characteristics of light in different polarization states at the material interface is utilized. For example, in the optical circulator 1310, when the incident light passes through the first polarization beam splitter, the S polarized light (the electric field vector is perpendicular to the incident plane) is reflected by the high reflectivity film layer, while the P polarized light (the electric field vector is parallel to the incident plane) is transmitted.

[0115] A reflector is an optical component that achieves high reflectivity through surface coating. Its core function is to change the direction of the light path without introducing significant optical loss.

[0116] A Faraday rotator is a non-reciprocal optical device based on the Faraday effect. It rotates the polarization direction of transmitted light under the action of an external magnetic field. The rotation direction is related to the direction of the magnetic field and has nothing to do with the propagation direction of the light.

[0117] The half-wave plate is a polarization control element based on the birefringence effect. It generates a phase difference of light through a crystal of a specific thickness, thereby controlling the rotation of the polarization direction of linearly polarized light. When the incident angle is 0°, the linearly polarized light can be rotated by 2θ (θ is the angle between the optical axis of the wave plate and the incident polarization direction). For example, when the optical axis is 22.5° to the incident polarization, the output polarization is rotated by 45°.

[0118] The half-wave plate is used in conjunction with the Faraday rotator to adjust the polarization state of the forward light to match the transmission axis of the second polarization beam splitter, for example, the S-polarized light rotated by 45° is further rotated by 45° to convert it into P-polarized light for transmission output.

[0119] The first polarized light is a linearly polarized light whose electric field vector vibration direction is perpendicular to the incident plane, for example, S-polarized light.

[0120] The second polarized light is another orthogonal component of the first polarized light, and the electric field vector vibration direction is parallel to the incident plane. For example, P polarized light, in a polarization beam splitter, P polarized light passes preferentially due to its transmission characteristics.

[0121] Figure 3 FIG. 4 shows a schematic diagram of the internal structure of a three-port optical circulator in a polychromator provided in an embodiment of the present application. Figure 3 As shown in (a):

[0122] The light will first hit the first polarization beam splitter, where the p-polarized light in the incident light is transmitted, and the s-polarized light is reflected to the first reflector. The s-polarized and p-polarized light then pass through the Faraday rotator, and the polarization state rotates 45° clockwise. After passing through the half-wave plate, the polarization state rotates 45° clockwise again. At this point, the original s-polarized light is converted into p-polarized light, and the original p-polarized light is converted into s-polarized light. The p-polarized light is transmitted through the second polarization beam splitter and emitted from the second port. The s-polarized light is reflected through the second reflector and then reflected by the second polarization beam splitter and also emitted from the second port. The two are recombined into the incident light and emitted from the second port.

[0123] It can be expressed as Jones matrix:

[0124] Incident light: =1;

[0125] Forward optical path:

[0126] S polarized light path: ; P polarized light path: ;

[0127] Through a Faraday rotator: ; ;

[0128] After half-wave plate: = ; = .

[0129] The direction of the light emitted from the second port remains unchanged compared to the incident light.

[0130] In the embodiment of the present application, by using two polarization beam splitters, two reflectors, a Faraday rotator and a half-wave plate to construct an optical circulator 1310, efficient directional transmission and isolation of optical signals are achieved. The incident light is precisely separated and the polarization state is converted and then recombined to ensure unidirectional transmission from the first port to the second port, avoid reverse reflection, and improve the stability and anti-interference ability of the system. Not only does it optimize the internal optical path management of the polychromator 100, but it also significantly improves the measurement accuracy and reliability of the plasma diagnostic system 10 and reduces the influence of stray light.

[0131] In one embodiment of the present application, the optical circulator 1310 is a three-port optical circulator, and the second lens barrel assembly 130 further includes a light devourer 1320, and the inner wall of the light devourer 1320 is coated with a light absorbing material;

[0132] The light swallower 1320 is connected to the third port of the optical circulator 1310;

[0133] The reverse optical path of the three-port optical circulator 1310 includes:

[0134] The stray light incident from the second port is incident on the second polarization beam splitter, and the stray light is separated into a third polarization light and a fourth polarization light;

[0135] The third polarized light is incident on the second reflector and is reflected. The reflected third polarized light is transmitted through the half-wave plate and rotated counterclockwise about the third polarized light direction. The rotated third polarized light is transmitted through the Faraday rotator and rotated counterclockwise about the third polarized light direction.

[0136] The fourth polarized light is transmitted through the half-wave plate, and rotated counterclockwise with the fourth polarized light direction as the axis. The rotated fourth polarized light is transmitted through the Faraday rotator, and rotated counterclockwise with the fourth polarized light direction as the axis. The rotated fourth polarized light is incident on the first reflector;

[0137] The third polarized light and the third polarized light are incident on the first polarization beam splitter, and are combined into stray light and incident into the light swallower 1320 from the third port.

[0138] The light devourer 1320 is an optical device for absorbing stray light, and has a specially designed cavity structure, and the inner wall of the light devourer 1320 is coated with a light absorbing material. The light devourer 1320 converts stray light (such as reflected light, scattered light) into heat energy or other forms of energy dissipation to prevent its reflection or secondary propagation from interfering with the main light path.

[0139] The third polarized light is a linearly polarized light whose electric field vector vibration direction is perpendicular to the incident plane, for example, S polarized light.

[0140] The fourth polarized light is another orthogonal component of the first polarized light, and the electric field vector vibration direction is parallel to the incident plane. For example, P polarized light, in a polarization beam splitter, P polarized light passes preferentially due to its transmission characteristics.

[0141] Figure 3 FIG. 1 shows a schematic diagram of the internal structure of a three-port optical circulator in a polychromator 100 provided in an embodiment of the present application. Figure 3 As shown in (b):

[0142] The light will first hit the second polarization beam splitter, where the p-polarized light in the incident light is transmitted, and the s-polarized light is reflected to the second reflector. The s-polarized light and the p-polarized light then pass through the half-wave plate, and the polarization state rotates 45° counterclockwise. After passing through the Faraday rotator, the polarization state rotates 45° clockwise. At this point, the original s-polarized light still exits in the s-polarization state, and the original p-polarized light still exits in the p-polarization state. The s-polarized light is reflected by the first polarization beam splitter and exits from the third port. The p-polarized light is reflected by the first reflector and then transmitted through the first polarization beam splitter and also exits from the third port. The two are recombined into stray light and emitted from the second port.

[0143] It can be expressed as Jones matrix:

[0144] Stray light: =1;

[0145] Reverse optical path:

[0146] S polarized light path: ; P polarized light path: ;

[0147] After half-wave plate: H ;H ;

[0148] After Faraday rotator: F = ; F = .

[0149] The light emitted from the third port has its direction changed compared to the stray light.

[0150] In the embodiment of the present application, the stray light problem in the polychromator 100 is effectively managed by introducing a three-port optical circulator and a light eater 1320. The reversely propagating stray light is separated, the polarization state is rotated, and then recombined and directed to the light eater 1320 to avoid interfering with the main optical path, which not only reduces the noise caused by reflection and scattering inside the system, but also significantly improves the purity and detection accuracy of the optical signal, ensuring the high stability and reliability of the plasma diagnostic system 10.

[0151] In one embodiment of the present application, the polychromator 100 further includes an optical fiber assembly 150;

[0152] The incident end of the optical fiber assembly 150 is connected to an optical fiber, and the optical fiber transmits the incident light from the nuclear fusion reaction device 20;

[0153] The output end of the optical fiber assembly 150 is connected to the first port of the optical circulator 1310 .

[0154] The optical fiber assembly 150 is a component that carries the optical fiber 140 and provides a connection interface. The optical fiber assembly 150 generally includes components such as an optical fiber adapter, an optical fiber connector, and an optical fiber fixing frame to ensure a reliable connection between the optical fiber 140 and the second lens barrel assembly 130 .

[0155] Optical fiber 140 is an optical medium for transmitting optical signals, and is generally composed of a core layer, a cladding layer, and a protective sheath. The core layer is a glass or plastic material with a high refractive index, which transmits optical signals; the cladding layer is a material with a low refractive index, which limits the propagation of optical signals in the core layer; and the protective sheath is a layer of durable material, which protects the optical fiber 140 from the influence of the external environment.

[0156] The optical fiber assembly 150 is connected to the second lens barrel assembly 130 through an optical fiber adapter, and can transmit the light beam from the nuclear fusion reaction device 20 to the polychromator 100 for analysis. The optical fiber 140 is usually made of high-precision, low-loss optical fiber materials to reduce the loss of optical signals during transmission. The design of the optical fiber assembly 150 enables the polychromator 100 to be flexibly connected to different nuclear fusion reaction devices 20, further improving the versatility and adaptability of the polychromator 100.

[0157] The output end of the optical fiber component 150 is connected to the first port of the optical circulator 1310. One feasible method is: the output end of the optical fiber component 150 is optically coupled to the first port of the optical circulator 1310 through a precision mechanical interface, and the optical signal output by the nuclear fusion reaction device 20 is introduced into the optical circulator 1310, while avoiding reverse reflection interference.

[0158] In the embodiment of the present application, efficient optical signal transmission between the nuclear fusion reaction device 20 and the polychromator 100 is achieved. The optical fiber assembly 150 ensures low-loss transmission of the optical signal and is connected to the first optical port of the optical circulator 1310 to avoid reverse reflection interference. Not only the stability and reliability of the system are improved, but also the versatility and adaptability of the equipment are enhanced, so that the polychromator 100 can be flexibly connected to different devices. In addition, the optical fiber assembly 150 effectively protects the optical signal from the influence of the external environment, further ensuring the measurement accuracy and data integrity of the plasma diagnostic system 10.

[0159] In one embodiment of the present application, the optical fiber assembly 150 includes a collimator lens assembly 1510, and the collimator lens assembly 1510 includes a cemented lens and a convex lens;

[0160] The optical axis of the collimating lens assembly 1510 is coaxial with the incident light path.

[0161] The collimator lens assembly 1510 is a composite optical system composed of a cemented lens and a convex lens, which effectively compresses the divergence angle of the incident light beam, so that the incident light enters the first port of the optical circulator 1310 in a collimated form, thereby meeting the requirements of the subsequent splitting light path for light beam collimation. For example, in the plasma diagnostic system 10, the spatial distribution of plasma scattered light has a high divergence characteristic, and direct coupling will cause light path deviation and energy loss due to beam divergence.

[0162] A cemented lens is a composite lens made of two optical materials with different refractive indices (such as fused silica and calcium fluoride) bonded by an optical cement, which is used to correct chromatic aberration and spherical aberration. The first surface of the cemented lens is concave, and the second surface is convex, and the curvature radii of the two are matched to achieve an achromatic design.

[0163] The convex lens is a short focal length single lens, located behind the cemented lens, and is used to perform secondary collimation and compression on the light beam transmitted by the cemented lens. The convex lens is usually made of fused quartz or glass.

[0164] In one embodiment, the optical axis of the collimating lens assembly 1510 is coaxial with the incident light path, which can be achieved through a mechanical adjustment mechanism. For example, the mounting flange of the optical fiber assembly 150 is provided with a three-axis adjustment knob (X / Y / Z translation), which can be used in conjunction with laser calibration to align the optical axis of the optical fiber 140 with the optical axis of the cemented lens-convex lens combination. After the adjustment is completed, the position is fixed by a locking bolt.

[0165] In the embodiment of the present application, the combination design of the cemented lens and the convex lens realizes efficient collimation and chromatic aberration compensation of the output light beam of the optical fiber 140. The achromatic characteristics of the cemented lens avoid the focus shift of light of different wavelengths, ensuring the consistency of wide spectrum collimation, and the secondary compression of the convex lens further optimizes the beam quality. The optical axis adjustment mechanism of the collimator lens group 1510 ensures the precise alignment of the incident light path and the internal light path of the polychromator 100, reduces the transmission loss caused by the optical axis offset, and significantly improves the signal-to-noise ratio of the Thomson scattering signal and the system measurement sensitivity.

[0166] Corresponding to at least one of the above embodiments, Figure 4 FIG. 1 shows a schematic diagram of a light path of a polychromator provided in an embodiment of the present application. The light path propagation process is as follows: Figure 4 As shown:

[0167] The incident light in the wavelength range of 913 nm-1090 nm is transmitted from the optical fiber 140 to the light inlet of the polychromator 100 , and after entering the polychromator 100 , is modulated into collimated light by the collimator lens assembly 1510 .

[0168] The collimated light enters the first port of the optical circulator 1310, is emitted from the second port of the optical circulator 1310, passes through the relay lens 1130 to reach the incident surface of the filter 1110 of the first split light path, and some light with a wavelength greater than 950nm±37nm is transmitted to the exit surface of the filter 1110. Only light with a wavelength of 950nm±37nm is transmitted on the exit surface of the filter 1110, and reaches the detector 1120 of the first split light path through the imaging lens 1140, and is converted into a digital electrical signal of the first split light path. The light with a wavelength exceeding 950±37nm transmitted on the incident surface of the filter 1110 in the first split light path is reflected by the exit surface of the filter 1110, enters the second port of the optical circulator 1310 in the reverse direction along the collimated light path, and finally exits from the third port of the optical circulator 1310, enters the light devourer 1320 and is absorbed.

[0169] Light in the wavelength range of 987nm-1090nm is reflected by the incident surface of the filter 1110 of the first split light path to the second split light path, and reaches the incident surface of the filter 1110 of the second split light path through the relay lens 1130. Some light in the range of greater than 1000nm±23nm will be transmitted to the exit surface of the filter 1110. Only light in the range of 1000nm±23nm is transmitted on the exit surface of the filter 1110, and passes through the imaging lens 1140. The light that reaches the detector 1120 of the second splitter optical path is converted into a digital electrical signal of the second splitter optical path. The light that exceeds the wavelength range of 1000±23nm and is transmitted through the incident surface of the filter 1110 of the second splitter optical path is reflected by the exit surface of the filter 1110, is reflected to the incident surface of the filter 1110 of the first splitter optical path, enters the second port of the optical circulator 1310 in the reverse direction, exits from the third port of the optical circulator 1310, and enters the light devourer 1320 to be absorbed.

[0170] Until all the light is transmitted by the corresponding split light path, all the excess light returns to the second port of the optical circulator 1310 through the original path, is emitted from the third port of the optical circulator 1310, and enters the light devourer 1320 to be absorbed.

[0171] The optical signals of the six split optical paths are all accurately collected.

[0172] Figure 4 The polychromator 100 shown has a simple optical path structure, is easy to implement, and is low in cost and easy to maintain. A wedge-shaped filter 1110 is designed in the optical path, so that the incident light has an incident angle of 0° on the second surface of the filter 1110, thereby avoiding the blue shift of the central wavelength and the widening of the bandwidth caused by the incident angle being greater than 0°, effectively solving the problem of crosstalk between optical path channels at all levels, and making the diagnosis result more real and reliable. In addition, an optical circulator 1310 and a light devourer 1320 are designed in the optical path system, and the light in the optical path structure of the polychromator 100 passes unidirectionally, and finally the stray light enters the light devourer 1320, which can effectively suppress the influence of the stray light.

[0173] Corresponding to at least one of the above embodiments, Figure 5 FIG. 4 shows a structural diagram of a polychromator provided by an embodiment of the present application. Figure 5 As shown:

[0174] The polychromator 100 is mainly composed of six first lens barrel assemblies 110 , one second lens barrel assembly 130 , one optical fiber assembly 150 , one optical path box 120 , and one optical fiber 140 .

[0175] Multiple components are installed on the optical path box 120. The inner wall of the optical path box 120 is provided with mounting positions for fixing other components, and bolt holes are provided on these mounting positions. Six first lens barrel assemblies 110 are installed on the inner wall of the optical path box 120 through lens flanges. One second lens barrel assembly 130 is also installed on the inner wall of the optical path box 120 through a lens flange. Optical fiber assembly 150: connected to the optical fiber adapter of the second lens barrel assembly 130, which includes an optical fiber 140, which transmits the light beam from the nuclear fusion reaction device 20. The light beam enters the optical path box 120 to form a reflected light path and is collected one by one by the six first lens barrel assemblies 110.

[0176] Figure 5 The polychromator 100 shown has a compact structure, greatly compresses the volume, and improves space utilization.

[0177] Corresponding to the above-mentioned polychromator 100, the present application also provides an embodiment of a plasma diagnostic system, Figure 6 1 is a schematic diagram of the structure of a plasma diagnostic system provided in one embodiment of the present application. The plasma diagnostic system 10 includes the polychromator 100 described above.

[0178] In the embodiment of the present application, high-precision measurement of plasma parameters is achieved by integrating the polychromator 100. The wedge-shaped filter 1110 in the polychromator 100 effectively compensates for the blue shift of the central wavelength and the widening of the bandwidth caused by oblique incidence, ensuring that the crosstalk phenomenon between each split light path is suppressed. This not only improves the stability and measurement accuracy of the system, but also enhances the adaptability to complex plasma environments. In addition, the application of the optical circulator 1310 further optimizes the optical signal transmission path, avoids reverse reflection interference, and enables the plasma diagnostic system 10 to provide more reliable data support in nuclear fusion research.

[0179] The above is a schematic scheme of a plasma diagnostic system 10 according to an embodiment of the present application. It should be noted that the technical scheme of the plasma diagnostic system 10 and the technical scheme of the polychromator 100 described above are of the same concept, and the details of the technical scheme of the plasma diagnostic system 10 that are not described in detail can be referred to the description of the technical scheme of the polychromator 100 described above.

[0180] Corresponding to the above-mentioned polychromator 100, the present application also provides an embodiment of a fusion reaction system, Figure 7 It is a structural schematic diagram of a fusion reaction system provided in one embodiment of the present application. The fusion reaction system 30 includes a nuclear fusion reaction device 20 and the above-mentioned plasma diagnostic system 10.

[0181] In the embodiment of the present application, the fusion reaction system 30 combines the nuclear fusion reaction device 20 with the plasma diagnostic system 10, providing a strong technical guarantee for the nuclear fusion experiment. The polychromator 100 in the plasma diagnostic system 10 uses a wedge-shaped filter 1110 and precision optical components, which significantly reduces the error in spectral analysis and improves the accuracy of plasma state monitoring.

[0182] The above is a schematic scheme of a fusion reaction system 30 of an embodiment of the present application. It should be noted that the technical scheme of the fusion reaction system 30 and the technical scheme of the polychromator 100 described above are of the same concept, and the details of the technical scheme of the fusion reaction system 30 that are not described in detail can all be referred to the description of the technical scheme of the polychromator 100 described above.

[0183] The above describes specific embodiments of the present 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 an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0184] Those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application. In the above embodiments, the description of each embodiment has its own emphasis, and for parts not described in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0185] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The above embodiments do not describe all the details in detail, nor do they limit the present application to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can understand and use the present application well.

Claims

1. A polychromator, characterized in that: The polychromator comprises a first lens barrel assembly, wherein the first lens barrel assembly comprises a filter and a detector of a wedge-shaped structure; The angle between the normal direction of the incident surface of the filter and the direction of the incident light is greater than the angle between the normal direction of the exit surface of the filter and the direction of the transmitted light; The incident surface and the exit surface of the filter are coated with filter films, and the filter films selectively transmit light of a specific wavelength in the incident light; The detector converts the light of the specific wavelength into an electrical signal.

2. The polychromator according to claim 1, characterized in that: The first lens barrel assembly further includes a relay lens, and the relay lens is a convex lens or a semi-convex lens; The incident light is incident on the first lens barrel assembly through the relay lens; The reflected light is emitted from the first lens barrel assembly through the relay lens, and the reflected light is the light reflected by the incident light on the incident surface of the filter.

3. The polychromator according to claim 1, characterized in that: The first lens barrel assembly further comprises an imaging lens, wherein the imaging lens is located between the filter and the detector, the imaging lens is a convex lens or a semi-convex lens, and the detector is located at the focus of the imaging lens; The incident light is incident on the detector through the imaging lens.

4. The polychromator according to claim 1, characterized in that: The polychromator further comprises an optical path box, and the first lens barrel assembly is multiple; The plurality of first lens barrel assemblies are cascaded and mounted on the inner wall of the optical path box, and adjacent first lens barrel assemblies are connected via a reflection optical path to form a multi-level splitting optical path; The incident surface of the filter in any first lens barrel assembly is coated with a filter film of target thickness, and the filter film of target thickness selectively transmits light of a wavelength corresponding to the target thickness in the incident light.

5. The polychromator according to claim 4, characterized in that: The polychromator further comprises a second lens barrel assembly, the second lens barrel assembly is mounted on the inner wall of the optical path box, the second lens barrel assembly is connected to the first lens barrel assembly via an incident optical path, and the second lens barrel assembly comprises an optical circulator; The optical circulator comprises at least two optical ports, the incident light path is incident into the first port, and the incident light path is incident into the optical path box from the second port.

6. The polychromator according to claim 5, characterized in that: The optical circulator comprises two polarization beam splitters, two reflectors, a Faraday rotator and a half-wave plate; The forward optical path of the optical circulator comprises: The incident light incident from the first port is incident on the first polarization beam splitter, and the incident light is separated into a first polarized light and a second polarized light; The first polarized light is incident on the first reflector and is reflected. The reflected first polarized light is transmitted through the Faraday rotator and rotated clockwise about the first polarized light direction. The rotated first polarized light is transmitted through the half-wave plate and rotated clockwise about the first polarized light direction. The second polarized light is transmitted through the Faraday rotator and rotated clockwise with the second polarized light direction as the axis. The rotated second polarized light is transmitted through the half-wave plate and rotated clockwise with the second polarized light direction as the axis. The rotated second polarized light is reflected on the second reflector. The first polarized light and the second polarized light are incident on the second polarization beam splitter, combined into incident light and emitted from the second port.

7. The polychromator according to claim 6, characterized in that: The optical circulator is a three-port optical circulator, and the second lens barrel assembly further comprises a light swallower, the inner wall of which is coated with a light absorbing material; The light swallower is connected to the third port of the optical circulator; The reverse optical path of the three-port optical circulator includes: The stray light incident from the second port is incident on the second polarization beam splitter, and the stray light is separated into a third polarized light and a fourth polarized light; The third polarized light is reflected by the second reflector, and the reflected third polarized light is transmitted through the half-wave plate, and rotated counterclockwise with the third polarized light direction as the axis, and the rotated third polarized light is transmitted through the Faraday rotator, and rotated counterclockwise with the third polarized light direction as the axis; The fourth polarized light is transmitted through the half-wave plate, and rotated counterclockwise with the fourth polarized light direction as the axis. The rotated fourth polarized light is transmitted through the Faraday rotator, and rotated counterclockwise with the fourth polarized light direction as the axis. The rotated fourth polarized light is incident on the first reflector; The first polarized light and the second polarized light are incident on the first polarization beam splitter, and are combined into stray light and incident into the light swallower from the third port.

8. The polychromator according to claim 5, characterized in that: The polychromator also includes a fiber optic assembly; The incident end of the optical fiber assembly is connected to an optical fiber, and the optical fiber transmits incident light from a nuclear fusion reaction device; The output end of the optical fiber assembly is connected to the first port of the optical circulator.

9. The polychromator according to claim 8, characterized in that The optical fiber assembly includes a collimator lens group, and the collimator lens group includes a cemented lens and a convex lens; The optical axis of the collimating lens group is coaxial with the incident light path.

10. A plasma diagnostic system, characterized in that: Comprising a polychromator as described in any one of claims 1-9.

11. A fusion reaction system, characterized in that: It comprises a nuclear fusion reaction device and the plasma diagnostic system as claimed in claim 10.

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