Method and system for correcting spectrum bending of plane grating spectrometer

Abstract

The invention provides a plane grating spectrometer spectrum bending correction method and system, and the method comprises the steps: S1, adjusting the focal lengths of a condensation system and a focusing collimation system of a plane grating spectrometer to be the same, and setting the magnification of the plane grating spectrometer to be 1; s2, setting an entrance slit and an exit slit of the focusing collimation system to be equal in height and width; s3, calculating to obtain the ratio of the focal length of the focusing collimation system to the height of the entrance slit; s4, according to the obtained ratio, calculating a relation correction coefficient between the emergent wavelengths with different proportions and heights of the slit and the central wavelength of the slit, and calculating a correction coefficient of the emergent wavelengths with different proportions and heights of the slit; and S5, according to the coefficients, carrying out spectrograph pixel-by-pixel spectral bending correction by matching with the pixel number of the optical receiving detector. According to the invention, the final calibration precision of the spectrometer can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of grating spectrometers, and in particular to a method and system for correcting spectral curvature of a plane grating spectrometer. Background Art

[0002] Grating spectrometers use various types of detectors to measure each spectral channel. In order to improve the application value of spectrometer data, accurate radiation calibration and spectral calibration are required before use. In the calibration process of existing spectrometers, the main technologies used are: using the monochromatic collimated light of the monochromator to obtain the spectral response function and spectral bandwidth for spectral correction; calibrating the coefficient matrix table for the responsivity of each detector pixel, and performing high-precision radiation calibration through parameter modification. In the process of monochromator spectral calibration and radiation calibration, the central wavelength accuracy and spectral bandwidth of each channel are the main factors affecting the calibration accuracy. From the grating spectroscopic theory, it can be seen that the slit width of the monochromator will affect the bandwidth, but when the slit width is less than 100μm, we can assume that the increment of the wavelength of the outgoing light starting from the edge of the slit width is linearly related to the increment of the width, which can be accurately expressed by the output center wavelength of the slit center. At the same time, the entrance slit length of the monochromator will cause spectral line bending, thereby affecting the output spectral position and energy distribution of the exit slit.

[0003] The traditional grating line bending correction method relies on the traditional analytical formula, and its derivation process requires the use of multiple approximate conditions, and the overall expression is relatively complex. Through the analysis of the actual spectrometer by the formula, it can be seen that the line bending has a great influence on the final calibration result of the detector pixel responsivity, and the actual spectrum measurement data shows that the deviation in the visible light band may reach 20nm, and the line bending is clearly visible. In order to eliminate the influence of the spectrum on the calibration of the spectrometer, multi-structure optical designs such as prism gratings or spectral correction of the pixel calibration coefficients of the final detector are generally adopted. The former method can reduce the value of the line bending to a certain extent, but the complex structure limits the subsequent correction accuracy; the second method is obviously suitable for the correction of the spectrometer based on the detector, but its accuracy is limited by the complexity and approximation of the line bending analysis equation, and cannot be effectively improved.

[0004] In the actual use of plane grating spectrometers, due to the existence of the slit height, the light incident from the edge of the entrance slit height will illuminate the grating at a certain angle to the main section after being collimated. The corresponding diffraction angle will cause the outgoing light to deviate from the main section and produce spectral line bending. Spectral line bending mainly affects the output spectral bandwidth of the spectrometer or monochromator, and ultimately affects the accuracy of spectral calibration. Summary of the invention

[0005] In view of the defects in the prior art, the present invention provides a method and system for correcting spectral curvature of a plane grating spectrometer.

[0006] According to a method and system for correcting spectral curvature of a plane grating spectrometer provided by the present invention, the scheme is as follows:

[0007] In a first aspect, a method for correcting spectral curvature of a plane grating spectrometer is provided, the method comprising:

[0008] Step S1: Adjust the focal lengths of the condensing system and the focusing collimation system of the plane grating spectrometer to be the same, and set the magnification of the plane grating spectrometer to 1;

[0009] Step S2: setting the entrance slit and exit slit of the focusing and collimating system to be of equal height and width;

[0010] Step S3: Calculate and obtain the ratio of the focal length of the focusing and collimating system to the height of the incident slit;

[0011] Step S4: Calculate the relationship correction coefficient between the wavelength of the slit at different ratios of height and the slit center wavelength, and the correction coefficient of the wavelength of the slit at different ratios of height according to the obtained ratio;

[0012] Step S5: According to various coefficients and in coordination with the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

[0013] Preferably, the step S1 comprises:

[0014] Step S1.1: Using the reflection imaging or projection imaging method, the focal length of the plane grating pre-focusing collimation system is set to f, and parallel light is incident on the plane grating;

[0015] Step S1.2: Using the reflection imaging or projection imaging method, the focal length of the plane grating post-focusing collimation system is set to f', so that f'=f, and the parallel light emitted by the plane grating is received.

[0016] Preferably, the step S2 comprises:

[0017] Step S2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer overall system, and set the incident slit height to 2h;

[0018] Step S2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

[0019] Preferably, the step S3 comprises: measuring the focal length f of the plane grating pre-focusing collimation system and the incident slit height h, and calculating the ratio k=h / f.

[0020] Preferably, in step S4, calculating the correction coefficient of the relationship between the emission wavelengths at different slit height ratios and the slit center wavelength includes:

[0021] According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained:

[0022]

[0023] The calculation of the wavelength correction coefficients for different ratios of slit heights includes:

[0024] Calculate and obtain the output wavelength λ' at the edge of the output slit:

[0025]

[0026] The correction factor is:

[0027]

[0028] Preferably, step S5 comprises:

[0029] Step S5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is:

[0030]

[0031] Step S5.2: Using the correction factor Spectral curvature correction is performed pixel by pixel on the detector column.

[0032] In a second aspect, a spectral curvature correction system for a plane grating spectrometer is provided, the system comprising:

[0033] Module M1: adjust the focal length of the plane grating spectrometer's focusing system and focusing collimation system to be the same, and set the plane grating spectrometer's magnification to 1;

[0034] Module M2: Set the entrance slit and exit slit of the focusing and collimating system to be of equal height and width;

[0035] Module M3: Calculate and obtain the ratio of the focal length of the focusing and collimating system to the height of the incident slit;

[0036] Module M4: Calculate the correction coefficient of the relationship between the wavelength of the slit at different height ratios and the central wavelength of the slit, and the correction coefficient of the wavelength of the slit at different height ratios according to the ratio obtained;

[0037] Module M5: Based on various coefficients and the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

[0038] Preferably, the module M1 comprises:

[0039] Module M1.1: Using the reflection imaging or projection imaging method, the focal length of the plane grating pre-focusing collimation system is set to f, and the plane grating is incident in the form of parallel light;

[0040] Module M1.2: Using the reflection imaging or projection imaging method, the focal length of the plane grating post-focusing collimation system is set to f', so that f'=f, and the parallel light emitted by the plane grating is received.

[0041] Preferably, the module M2 comprises:

[0042] Module M2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer as a whole system, and set the incident slit height to 2h;

[0043] Module M2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

[0044] Preferably, the module M3 comprises: measuring the focal length f of the plane grating pre-focusing collimation system and the incident slit height h, and calculating the ratio k=h / f;

[0045] In the module M4, the correction coefficient for calculating the relationship between the wavelength of the slit at different ratios of height and the slit center wavelength includes:

[0046] According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained:

[0047]

[0048] The calculation of the wavelength correction coefficients for different ratios of slit heights includes:

[0049] Calculate the wavelength at the edge of the exit slit:

[0050]

[0051] The correction factor is:

[0052]

[0053] The module M5 comprises:

[0054] Module M5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is:

[0055]

[0056] Module M5.2: Using Correction Factors Spectral curvature correction is performed pixel by pixel on the detector column.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] The method for correcting the output bandwidth change of a plane grating spectrometer caused by spectrum bending provided by the present invention does not use the deduction process of approximate replacement, and obtains a method with a simple form and higher calculation accuracy, thereby improving the final calibration accuracy of the spectrometer. The method has high economic value and use value in multiple fields of application of plane grating spectrometers.

[0059] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0061] Figure 1 It is a schematic diagram of the overall process of the present invention. DETAILED DESCRIPTION

[0062] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0063] The embodiment of the present invention provides a method for correcting spectral curvature of a plane grating spectrometer, referring to Figure 1 As shown, the method specifically includes the following contents:

[0064] Step S1: Adjust the focal lengths of the condensing system and the focusing collimation system of the plane grating spectrometer to be the same, and set the magnification of the plane grating spectrometer to 1.

[0065] The step S1 specifically includes:

[0066] Step S1.1: setting the focal length of the plane grating pre-focusing collimation system to f, and incident on the plane grating in the form of parallel light;

[0067] Step S1.2: Set the focal length of the plane grating post-focusing collimation system to f', so that f'=f, and receive the parallel light emitted by the plane grating.

[0068] Step S2: setting the entrance slit and exit slit of the focusing and collimating system to be of equal height and width.

[0069] The step S2 specifically includes:

[0070] Step S2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer overall system, and set the incident slit height to 2h;

[0071] Step S2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

[0072] Step S3: Calculate and obtain the ratio of the focal length of the focusing and collimating system to the height of the incident slit.

[0073] Specifically, the focal length f of the plane grating pre-focusing collimation system and the incident slit height h are measured, and the ratio k=h / f is calculated.

[0074] Step S4: Calculate the correction coefficient of the relationship between the wavelength of the slit at different ratios of height and the central wavelength of the slit, and the correction coefficient of the wavelength of the slit at different ratios of height according to the obtained ratio.

[0075] Among them, the correction coefficients for calculating the relationship between the emission wavelength at different slit height ratios and the slit center wavelength include:

[0076] According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained:

[0077]

[0078] Calculation of the wavelength correction factor for different ratios of slit heights includes:

[0079] Calculate the wavelength at the edge of the exit slit:

[0080]

[0081] The correction factor is:

[0082]

[0083] Step S5: According to various coefficients and in coordination with the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

[0084] The step S5 specifically includes:

[0085] Step S5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is:

[0086]

[0087] Step S5.2: Using the correction factor Spectral curvature correction is performed pixel by pixel on the detector column.

[0088] The present invention also provides a plane grating spectrometer spectrum curvature correction system, which can be implemented by executing the process steps of the plane grating spectrometer spectrum curvature correction method, that is, those skilled in the art can understand the plane grating spectrometer spectrum curvature correction method as a preferred implementation of the plane grating spectrometer spectrum curvature correction system. The system specifically includes the following contents:

[0089] Module M1: Adjust the focal lengths of the plane grating spectrometer's focusing system and focusing collimation system to be the same, and set the plane grating spectrometer's magnification to 1.

[0090] The module M1 specifically includes:

[0091] Module M1.1: Using the reflection imaging or projection imaging method, the focal length of the plane grating pre-focusing collimation system is set to f, and the plane grating is incident in the form of parallel light;

[0092] Module M1.2: Using the reflection imaging or projection imaging method, the focal length of the plane grating post-focusing collimation system is set to f', so that f'=f, and the parallel light emitted by the plane grating is received.

[0093] Module M2: Set the entrance slit and exit slit of the focusing and collimating system to be of equal height and width.

[0094] The module M2 specifically includes:

[0095] Module M2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer as a whole system, and set the incident slit height to 2h;

[0096] Module M2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

[0097] Module M3: Calculate the ratio of the focal length of the focusing and collimating system to the height of the entrance slit.

[0098] Specifically, the focal length f of the plane grating pre-focusing collimation system and the incident slit height h are measured, and the ratio k=h / f is calculated.

[0099] Module M4: Calculate the correction coefficient of the relationship between the wavelength of the slit at different height ratios and the slit center wavelength, and the correction coefficient of the wavelength of the slit at different height ratios based on the obtained ratio.

[0100] Among them, the correction coefficients for calculating the relationship between the emission wavelength at different slit height ratios and the slit center wavelength include:

[0101] According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained:

[0102]

[0103] Calculation of the wavelength correction factor for different ratios of slit heights includes:

[0104] Calculate the wavelength at the edge of the exit slit:

[0105]

[0106] The correction factor is:

[0107]

[0108] Module M5: Based on various coefficients and the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

[0109] The module M5 specifically includes:

[0110] Module M5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is:

[0111]

[0112] Module M5.2: Using Correction Factors Spectral curvature correction is performed pixel by pixel on the detector column.

[0113] Next, the present invention will be described in more detail through specific operations in reality.

[0114] The present invention provides a method for correcting spectral curvature of a high-precision plane grating spectrometer, such as Figure 1 As shown, the following steps are included:

[0115] Step 1: Design the plane grating spectrometer focusing system and collimation system to have the same focal length and keep the magnification of the spectrometer system at 1.

[0116] Step 1.1: Using the reflection imaging or projection imaging method, design the plane grating pre-focusing collimation system with a focal length of f=100 mm, and incident on the plane grating in the form of parallel light.

[0117] Step 1.2: Using the reflection imaging or projection imaging method, design the plane grating post-focusing collimation system with a focal length of f', so that f'=f=100mm, and receive the parallel light emitted by the plane grating.

[0118] Step 2: Design the entrance slit and exit slit to be equal in height and width, and determine the ratio of the focal length of the grating spectrometer to the entrance slit height.

[0119] Step 2.1: The incident slit of the plane grating pre-focusing collimation system described in the above scheme is used as the incident slit of the grating spectrometer overall system, and the incident slit height is designed to be 2h=20mm.

[0120] Step 2.2: The exit slit of the plane grating post-focusing collimation system described in the above scheme is used as the exit slit of the grating spectrometer overall system, ensuring that the exit slit height 2h'=2h=20mm.

[0121] Step 2.3: Measure the focal length f and the incident slit height h of the plane grating pre-focusing collimation system described in the above scheme, and calculate the ratio k=h / f=0.1.

[0122] Step 3: Accurately calculate and obtain the correction coefficient of the relationship between the emission wavelength at different slit height ratios and the slit center wavelength.

[0123] Step 3.1: According to the above scheme, k = h / f = 0.1, the relationship between the wavelength shift Δλ of the edge of the exit slit and the wavelength λ of the center of the slit = 600 nm is obtained:

[0124] Step 3.2: Calculate the wavelength at the edge of the exit slit The correction factor is

[0125]

[0126] Step 4: Perform spectral curvature correction on a pixel-by-pixel basis in accordance with the number of pixels of the optical receiving detector.

[0127] Step 4.1: Take the number of detector pixels as 2l = 20, and the correction coefficients of the spectral curvature of each pixel from n = 1 to n = 10 symmetrically from the center pixel of the detector are: The pixel-by-pixel correction coefficients are shown in Table 1 below:

[0128] Table 1: Pixel-by-pixel correction coefficients

[0129]

[0130] Step 4.2: Use the pixel-by-pixel correction coefficient table described in the above scheme to perform spectral curvature correction on the column detector pixel by pixel. According to the above scheme, when the slit center wavelength λ=600nm, the output spectral wavelength corresponding to each pixel is shown in Table 2 below:

[0131] Table 2: Pixel-by-pixel correction output spectral wavelength

[0132]

[0133] In order to illustrate the practicality of the method in the present invention, the prior art is selected as a comparative method. The prior art generally uses the plane grating equation to calculate, and the wavelength incident at the edge of the slit with a height of 2h is the same as the central wavelength, both of which are λ 0 The diffraction polar angle of monochromatic light is θ m2 The central wavelength λ in the main section 0 The incident angle of the light ray is θ m1 The angle difference Δθ is approximately,

[0134]

[0135] Where d is the grating constant, which has the same unit as λ 0 Same; θ m2→1 represents the diffraction polar angle θ m2 The unit of the projection angle Δθ is radians after projection in the main section. According to the above formula, the relationship between the wavelength of the spectrum received at the edge of the detector and the wavelength offset Δλ of the slit center wavelength can be deduced as follows:

[0136]

[0137] The above analysis shows that when using the traditional method to correct the spectral curvature of the spectrometer output, it is necessary to use design parameters such as the grating constant, the incident light angle, and the grating order. At the same time, the calculation process uses a small amount of approximate simplified conditions. The accuracy of the derived calculation formula is lower than that of the method provided by the present invention that does not use approximate conditions. At the same time, because it contains complex forms such as trigonometric functions, the accuracy will continue to decrease when the detector is calibrated pixel by pixel.

[0138] The method for correcting the output bandwidth change of a plane grating spectrometer caused by spectrum bending provided by the present invention does not use the deduction process of approximate replacement, and the obtained parameters are concise and the calculation is accurate, thereby improving the output pixel-level calibration accuracy of the spectrometer, and at the same time reducing the requirements for grating parameters and light path incident design, improving the flexibility of spectrometer design upgrades, and reducing the limitations of output bandwidth correction. The method has high economic value and use value in multiple fields of application of plane grating spectrometers.

[0139] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0140] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A method for correcting spectral curvature of a plane grating spectrometer, characterized in that: include: Step S1: Adjust the focal lengths of the condensing system and the focusing collimation system of the plane grating spectrometer to be the same, and set the magnification of the plane grating spectrometer to 1; Step S2: setting the entrance slit and exit slit of the focusing and collimating system to be of equal height and width; Step S3: Calculate and obtain the ratio of the focal length of the focusing and collimating system to the height of the incident slit; Step S4: Calculate the relationship correction coefficient between the wavelength of the slit at different ratios of height and the slit center wavelength, and the correction coefficient of the wavelength of the slit at different ratios of height according to the obtained ratio; Step S5: According to various coefficients and in coordination with the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

2. The method for correcting spectral curvature of a plane grating spectrometer according to claim 1, characterized in that: The step S1 comprises: Step S1.1: Using the reflection imaging or projection imaging method, the focal length of the plane grating pre-focusing collimation system is set to f, and parallel light is incident on the plane grating; Step S1.2: Using the reflection imaging or projection imaging method, the focal length of the plane grating post-focusing collimation system is set to f', so that f'=f, and the parallel light emitted by the plane grating is received.

3. The method for correcting spectral curvature of a plane grating spectrometer according to claim 1, characterized in that: The step S2 comprises: Step S2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer overall system, and set the incident slit height to 2h; Step S2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

4. The method for correcting spectral curvature of a plane grating spectrometer according to claim 1, characterized in that: The step S3 comprises: measuring the focal length f of the plane grating pre-focusing collimation system and the incident slit height h, and calculating the ratio k=h / f.

5. The method for correcting spectral curvature of a plane grating spectrometer according to claim 4, characterized in that: In step S4, calculating the correction coefficient of the relationship between the emission wavelengths at different slit height ratios and the slit center wavelength includes: According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained: The calculation of the wavelength correction coefficients for different ratios of slit heights includes: Calculate the wavelength at the edge of the exit slit: The correction factor is:

6. The method for correcting spectral curvature of a plane grating spectrometer according to claim 4, characterized in that: The step S5 comprises: Step S5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is: Step S5.2: Using the correction factor Spectral curvature correction is performed pixel by pixel on the detector column.

7. A spectral curvature correction system for a plane grating spectrometer, characterized in that: include: Module M1: adjust the focal length of the plane grating spectrometer's focusing system and focusing collimation system to be the same, and set the plane grating spectrometer's magnification to 1; Module M2: Set the entrance slit and exit slit of the focusing and collimating system to be of equal height and width; Module M3: Calculate and obtain the ratio of the focal length of the focusing and collimating system to the height of the incident slit; Module M4: Calculate the correction coefficient of the relationship between the wavelength of the slit at different height ratios and the central wavelength of the slit, and the correction coefficient of the wavelength of the slit at different height ratios according to the ratio obtained; Module M5: Based on various coefficients and the number of pixels of the optical receiving detector, the spectrometer performs pixel-by-pixel spectrum curvature correction.

8. The spectral curvature correction system for a plane grating spectrometer according to claim 7, characterized in that: The module M1 comprises: Module M1.1: Using the reflection imaging or projection imaging method, the focal length of the plane grating pre-focusing collimation system is set to f, and the plane grating is incident in the form of parallel light; Module M1.2: Using the reflection imaging or projection imaging method, the focal length of the plane grating post-focusing collimation system is set to f', so that f'=f, and the parallel light emitted by the plane grating is received.

9. The spectral curvature correction system for a plane grating spectrometer according to claim 7, characterized in that: The module M2 comprises: Module M2.1: Use the incident slit of the plane grating pre-focusing collimation system as the incident slit of the grating spectrometer as a whole system, and set the incident slit height to 2h; Module M2.2: Use the exit slit of the plane grating post-focusing collimation system as the exit slit of the grating spectrometer overall system, and keep the exit slit height 2h'=2h.

10. The spectral curvature correction system for a plane grating spectrometer according to claim 7, characterized in that: The module M3 comprises: measuring the focal length f of the plane grating pre-focusing collimation system and the incident slit height h, and calculating the ratio k=h / f; In the module M4, the correction coefficient for calculating the relationship between the wavelength of the slit at different ratios of height and the slit center wavelength includes: According to the ratio k = h / f, the relationship between the wavelength offset Δλ at the edge of the exit slit and the wavelength λ at the center of the slit is obtained: The calculation of the wavelength correction coefficients for different ratios of slit heights includes: Calculate the wavelength at the edge of the exit slit: The correction factor is: The module M5 comprises: Module M5.1: The number of detector pixels is (2l+1), where the center pixel of the detector is 0, and l represents the pixel number of the upper and lower symmetrical edge of the detector. At this time, the correction coefficient of the spectral curvature of the nth pixel of the upper and lower symmetrical pixel is: Module M5.2: Using Correction Factors Spectral curvature correction is performed pixel by pixel on the detector column.

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