Method and system for constructing echelle grating spectrometer two-dimensional spectrogram restoration model

Abstract

The invention discloses a method and a system for constructing a two-dimensional spectrogram reduction model of an echelle grating spectrometer, belongs to the technical field of two-dimensional spectrogram reduction of the echelle grating spectrometer, and solves the problem that an existing echelle grating spectrometer spectrogram reduction model shows relatively large errors in an inflatable broadband spectrum detection range. Establishing the position relation between the echelle grating diffraction Y-direction wavelength and the detector pixel; establishing a position relation between prism dispersion X-direction wavelength and a detector pixel; constructing a two-dimensional spectrogram reduction model of the echelle grating spectrometer based on the established position relationship between the diffraction Y-direction wavelength of the echelle grating and the pixel of the detector and the established position relationship between the dispersion X-direction wavelength of the prism and the pixel of the detector; and calibrating the two-dimensional spectrogram reduction model of the echelle grating spectrometer based on a standard light source, and optimizing optical structure parameters in the two-dimensional spectrogram reduction model to obtain an optimal two-dimensional spectrogram reduction model of the echelle grating spectrometer.

Description

Technical Field

[0001] The present invention relates to the technical field of two-dimensional spectrum restoration of an echelle grating spectrometer, and in particular to a method and system for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer. Background Art

[0002] As an indispensable means in scientific research, spectral analysis has increasingly higher requirements for its spectral coverage, resolution, measurement accuracy and other performances with the continuous advancement of science and technology. Especially in the far ultraviolet band, it is of great significance for exploring the microstructure of matter, analyzing environmental pollutants, and observing biological reaction mechanisms. The echelle grating spectrometer has the advantages of wide spectral range, high spectral resolution, high energy efficiency, and small size. It can obtain spectral images of the entire spectrum through a single measurement. It is the preferred spectrometer for advanced spectral analysis systems such as laser induced plasma spectroscopy, microwave plasma torch, and inductively coupled plasma atomic emission spectroscopy.

[0003] The traditional echelle grating spectrometer is mainly designed for near-ultraviolet band, visible light band, infrared wave, etc., and the spectrum within this range can be transmitted in the air. When the spectrometer detection range covers the far-ultraviolet band, due to the strong absorption of the ultraviolet spectrum by substances such as water vapor, oxygen, and carbon dioxide in the air, the transmission efficiency and signal-to-noise ratio of the spectral signal are greatly limited, making the detector unable to detect the far-ultraviolet spectrum. In order to solve this problem, inert gas was used as the spectral transmission medium in the process of developing the echelle grating spectrometer. Inert gas has low absorption and stable chemical properties in the far-ultraviolet band, and is an ideal choice for the far-ultraviolet spectrum transmission medium.

[0004] Different from the spectrometer in the traditional atmospheric environment, when the spectrometer is filled with inert gas, although the transmission efficiency of the spectral signal is improved, it will inevitably cause the light transmission medium to change, which directly affects the optical imaging quality and resolution of the spectrometer. The change of the light transmission medium will cause the spectral imaging position to shift, thereby reducing the accuracy and reliability of the spectrum restoration of the echelle grating spectrometer. In addition, the spectrum restoration model of the traditional echelle grating spectrometer is often based on the air medium design and relies on a simplified optical design model, ignoring the complex optical design structure and the change of the refractive index of the transmission medium, which directly leads to large errors in the gas-filled wide-band spectrum detection range.

[0005] In summary, the existing echelle grating spectrometer spectrum restoration model ignores the complex optical design structure and the change of the refractive index of the transmission medium, which directly leads to large errors in the gas-filled wide-band spectral detection range. Summary of the invention

[0006] The invention solves the problem that the existing echelle grating spectrometer spectrum restoration model exhibits large errors within the gas-filled wide-band spectrum detection range.

[0007] The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to the present invention comprises the following steps: Step S1, by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes, the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel is established; Step S2, establishing the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; Step S3, constructing a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; Step S4, calibrating the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizing the optical structure parameters in the two-dimensional spectrum restoration model, and obtaining the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0008] Furthermore, in one embodiment of the present invention, in the step S1, the consideration of the change in the refractive index of the medium through which the light passes is to introduce the refractive index parameter of the light transmission gas medium.

[0009] Further, in one embodiment of the present invention, in the step S1, the relationship between the wavelength of the echelle grating diffraction in the Y direction and the position of the detector pixel is established as follows: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the Y direction of the echelle grating diffraction, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the Y direction of the echelle grating diffraction, and the offset of the light in the Y direction of the detector is obtained.

[0010] Furthermore, in one embodiment of the present invention, the offset of the light in the Y direction of the detector is specifically: ; in, is the offset of the light in the Y direction of the detector, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, To correct the distance from the rear surface of the lens to the detector, is the angle between the light ray and the optical axis.

[0011] Further, in one embodiment of the present invention, in the step S2, the relationship between the prism dispersion wavelength in the X direction and the detector pixel position is established, specifically: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the X direction of prism dispersion, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the X direction of prism dispersion, and the offset of the light in the X direction of the detector is obtained.

[0012] Furthermore, in one embodiment of the present invention, the light offset in the detector X direction is specifically: ; in, is the offset of the light in the detector X direction, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, is the distance from the focusing lens to the front surface of the correction lens, To correct for the thickness of the lens, To correct the distance from the rear surface of the lens to the detector, is the distance from the intersection of the front surface of the correction lens and the optical axis to the center of the focusing lens, is the distance from the intersection of the front surface of the correction lens and the optical axis to the intersection of the back surface of the correction lens and the optical axis. is the angle between the light ray and the optical axis.

[0013] Furthermore, in one embodiment of the present invention, if the correction lens comprises a plurality of lens groups, the light offset in the Y direction of the detector is specifically: ; in, To correct the lens contains multiple mirror groups, the light is offset in the Y direction of the detector, is the distance between the light and the center of the focusing lens in the Y direction, , , , , , and are all the offsets of the light in the Y direction. The medium and correction lens parameters that the light passes through in the Y direction are different, and the offsets are also different. and are all positive integers, and and Not equal to 1, 2, 3, 4 and 5, ≠ ; Then the light is offset in the X direction of the detector, specifically: ; in, To correct the lens, which contains multiple mirror groups, the light is offset in the X direction of the detector. The distance between the light and the center of the focusing lens in the X direction, , , , , , and The offsets are all in the X direction. The offsets are different when the medium and correction lens parameters that the light passes through in the X direction are different.

[0014] Further, in one embodiment of the present invention, solving the , , , , , , , , , , , , and When calculating the refractive index of a medium, the principle of geometric optics is used and the change of the refractive index of the medium through which the light passes is considered.

[0015] Further, in one embodiment of the present invention, the step S4, calibrating the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source to optimize the optical structure parameters in the two-dimensional spectrum restoration model, comprises the following steps: Step S401, obtaining the optical structure initialization parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer; The optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer include the medium refractive index, the grating incident angle, the prism vertex angle, the grating offset angle and the system focal length; Step S402, traversing the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer, and generating the fitting coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer; Step S403, based on the characteristic wavelength of the standard light source, respectively calculating the mean square error between the fitted coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer and the actual coordinate position; Step S404, determine whether the mean square error sum is minimum, if yes, execute step S405, if no, return to step S402; Step S405, completing the correction and optimization of the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0016] The system for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to the present invention comprises the following modules: The first module is to establish the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; The second module is to establish the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; A construction module is constructed to construct a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; The calibration optimization module calibrates the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizes the optical structure parameters in the two-dimensional spectrum restoration model, and obtains the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0017] The present invention solves the problem that the existing echelle grating spectrometer spectrum restoration model shows large errors in the inflatable wide-band spectrum detection range. Specific beneficial effects include: 1. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in the present invention adopts a mathematical modeling method, calculates the light transmission path and imaging position through the principle of geometric optics, constructs a mapping relationship between the wavelength and the coordinate position of the detector pixel, and realizes accurate conversion of the spectrum, thereby solving the problem that the existing echelle grating spectrometer spectrum restoration model exhibits large errors within the inflatable wide-band spectrum detection range; 2. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in the present invention performs geometric optical calculations when constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer, fully considering the change in the refractive index of the light transmission medium, ensuring the accuracy of the imaging position calculation, thereby solving the problem in the prior art that the refractive index of the medium inside the echelle grating spectrometer is significantly affected by the inert gas filling; 3. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in the present invention optimizes the parameters of the medium refractive index, grating incident angle, prism vertex angle, grating offset angle and system focal length in the constructed two-dimensional spectrum restoration model of an echelle grating spectrometer by correcting the constructed two-dimensional spectrum restoration model of an echelle grating spectrometer, thereby improving the accuracy and reliability of the two-dimensional spectrum restoration model of an echelle grating spectrometer; 4. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in the present invention improves the accuracy of the two-dimensional spectrum restoration model of an echelle grating spectrometer by accurately analyzing the complex influence of the correction lens on the light transmission path; The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in the present invention is used to restore the two-dimensional spectrum of an inflatable wide-band echelle grating spectrometer whose spectral range covers the far ultraviolet band. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which: Figure 1 1 is a diagram showing the relationship between the focusing mirror and the correction lens in the Y direction of the mid-step grating diffraction described in the first embodiment; Figure 2 is a graph showing the relationship between the focusing lens and the correction lens in the X-direction offset of the prism dispersion described in the first embodiment; Figure 3 It is a diagram of the two-dimensional spectrum restoration model of the constructed echelle grating spectrometer described in the first embodiment; Figure 4 This is a result diagram of the optical structure parameters in the two-dimensional spectrum restoration model of the medium-step grating spectrometer described in the third embodiment not being optimized; Figure 5 This is a diagram showing the optimization results of the optical structure parameters in the two-dimensional spectrum restoration model of the medium-step grating spectrometer described in Implementation Method 3. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe various embodiments of the present invention in conjunction with the accompanying drawings. The embodiments described with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0020] Implementation method 1: The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in this implementation method comprises the following steps: Step S1, by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes, the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel is established; Step S2, establishing the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; Step S3, constructing a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; Step S4, calibrating the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizing the optical structure parameters in the two-dimensional spectrum restoration model, and obtaining the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0021] In this embodiment, in the step S1, the consideration of the change in the refractive index of the medium through which the light passes is to introduce the refractive index parameter of the light transmission gas medium.

[0022] In this embodiment, in step S1, the relationship between the wavelength of the echelle grating diffraction in the Y direction and the position of the detector pixel is established as follows: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the Y direction of the echelle grating diffraction, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the Y direction of the echelle grating diffraction, and the offset of the light in the Y direction of the detector is obtained.

[0023] In this embodiment, the light offset in the Y direction of the detector is specifically: ; in, is the offset of the light in the Y direction of the detector, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, To correct the distance from the rear surface of the lens to the detector, is the angle between the light ray and the optical axis.

[0024] In this embodiment, in step S2, the relationship between the prism dispersion wavelength in the X direction and the detector pixel position is established as follows: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the X direction of prism dispersion, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the X direction of prism dispersion, and the offset of the light in the X direction of the detector is obtained.

[0025] In this embodiment, the light offset in the detector X direction is specifically: ; in, is the offset of the light in the detector X direction, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, is the distance from the focusing lens to the front surface of the correction lens, To correct for the thickness of the lens, To correct the distance from the rear surface of the lens to the detector, is the distance from the intersection of the front surface of the correction lens and the optical axis to the center of the focusing lens, is the distance from the intersection of the front surface of the correction lens and the optical axis to the intersection of the back surface of the correction lens and the optical axis. is the angle between the light ray and the optical axis.

[0026] In the prior art, the spectrum restoration model of the medium-step grating spectrometer is often based on the air medium design and relies on a simplified optical design model, ignoring the complex optical design structure and the change of the refractive index of the light transmission medium, which directly leads to large errors in the air-filled wide-band spectral detection range.

[0027] In order to solve the above technical problems, this embodiment proposes a method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer, comprising the following steps: Step S1, through the principle of geometric optics and considering the change of the refractive index of the medium through which the light passes, the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel is established, specifically: When establishing the two-dimensional spectrum restoration model of the echelle grating spectrometer in the Y direction of the echelle grating diffraction, a correction lens is used between the focusing mirror and the detector, which is a CCD detector. The offset relationship between the focusing mirror and the correction lens in the Y direction of the echelle grating diffraction is as follows: Figure 1 As shown in the figure, is the center of the front surface of the focusing mirror, is the distance between the light and the center of the focusing lens in the Y direction, is the distance from the focusing lens to the front surface of the correction lens, To correct for the thickness of the lens, To correct the distance from the rear surface of the lens to the detector, and are the radii of curvature of the front and rear surfaces of the correction lens, respectively. The intersection point of the light along the propagation direction and the front surface of the correction lens is , and are the incident angle and refraction angle of the light on the front surface of the correction lens, for The intersection with the optical axis, The distance is , The distance is , the offset of the light in the Y direction is , the angle between the light ray and the optical axis is The intersection point of the light passing through the correction lens and the rear surface is , and are the incident angle and refraction angle of the light on the rear surface of the correction lens, for The intersection with the optical axis, The distance is , The distance is , the offset in the Y direction is , the angle between the light ray and the optical axis is The light passes through the medium and reaches the detector target surface. The offset in the Y direction is , the angle between the light ray and the optical axis is , so the actual Y-direction offset of the light It can be expressed as: ; To solve When the light passes through the front surface of the correction lens, the intersection point of the light along the propagation direction and the correction lens Construct the right triangle AY1O1. According to the Pythagorean theorem, we have: ; in, ; ; available The expression is: ; So there is, ; Taking into account the changes in the light transmission medium, is the refractive index of the light transmission medium, To correct the refractive index of the lens, according to trigonometric functions and the law of refraction: ; To solve When the light passes through the rear surface of the correction lens, the intersection point of the light and the rear surface is Construct a right triangle BY2O2, let According to the Pythagorean theorem, we can get The expression is: ; So there is, ; Similarly, considering the change of the light transmission medium, according to trigonometric functions and the law of refraction: ; So there is, ; Therefore, in the Y direction of the echelle grating diffraction, the actual offset of the light is It can be expressed as: ; The parameters in the above formula are all based on the wavelength of the incident light. Therefore, the incident light wavelength can be established There is a one-to-one correspondence between the Y direction coordinates. In this way, the Y direction position coordinates of the spectrum on the detector can be solved.

[0028] Step S2, through the principle of geometric optics and considering the change of the refractive index of the medium through which the light passes, establish the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel, specifically: When establishing the two-dimensional spectrum restoration model of the medium-step grating spectrometer in the prism dispersion X direction, a correction lens is also used between the focusing mirror and the detector. The detector is a CCD detector. The offset relationship between the focusing mirror and the correction lens in the prism dispersion X direction is as follows: Figure 2 As shown in the figure, For any wavelength spectrum incident on the focusing mirror position, is the center of the front surface of the focusing mirror, The distance between the light and the center of the focusing lens in the X direction, To focus the center of the mirror ball, , is the curvature radius of the focusing lens, For the image surface, , is the focal length, is the light’s exit point from the prism, is the emission angle of the reference wavelength on the prism, then the angle ∠QUP between the emission light of any wavelength on the prism and the emission light of the reference wavelength can be expressed as: ; is the distance from the focusing lens to the front surface of the correction lens, To correct for the thickness of the lens, To correct the distance from the rear surface of the lens to the detector, and are the radii of curvature of the front and rear surfaces of the correction lens, respectively. is the intersection point of the light along the propagation direction and the front surface of the correction lens, and are the incident angle and refraction angle of the light on the front surface of the correction lens, for The intersection with the optical axis, The distance is , The distance is , is the offset of the light in the X direction, is the angle between the light ray and the optical axis. is the intersection point between the light passing through the correction lens and the rear surface, and are the incident angle and refraction angle of the light on the rear surface of the correction lens, for The intersection with the optical axis, The distance is , The distance is , is the offset of the light in the X direction, is the angle between the light and the optical axis. The light passes through the medium and reaches the detector target surface. is the offset of the light in the X direction, The angle between the light and the optical axis. Therefore, in the X direction, the light is actually offset in the X direction. It can be expressed as: ; in, ; To solve When the light passes through the front surface of the correction lens, the intersection point of the light along the propagation direction and the correction lens Construct the right triangle EX1O1. According to the Pythagorean theorem, we have: ; in, ; ; make ,available The expression is: ; So there is, ; Taking into account the change of the light transmission medium, according to trigonometric functions and the law of refraction, is the refractive index of the light transmission medium, To correct for the refractive index of the lens, the following equation is obtained: ; To solve When the light passes through the rear surface of the correction lens, the intersection point of the light and the rear surface is Construct a right triangle FX2O2, let According to the Pythagorean theorem, we can get The expression is: ; So there is, ; Similarly, considering the change of the light transmission medium, according to trigonometric functions and the law of refraction: ; So there is, It can be expressed as: ; Therefore, in the prism dispersion direction, the actual displacement of the light in the X direction is It can be expressed as: ; The parameters in the above formula are all based on the wavelength of the incident light. Therefore, the incident light wavelength can be established There is a one-to-one correspondence between the X-direction coordinates and the X-direction coordinates. This method can be used to solve the X-direction position coordinates of the spectrum on the detector.

[0029] Step S3, constructing a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; Based on the established relationship between the Y-direction wavelength of the echelle grating diffraction and the detector pixel position, as well as the established relationship between the X-direction wavelength of the prism dispersion and the detector pixel position, a complete two-dimensional spectrum restoration model for the echelle grating spectrometer is constructed.

[0030] Based on the principle of geometric optics, the wavelength of the incident light is expressed The mapping relationship between the Y direction and the X direction is With the detector The correlation matrix between pixels is expressed as: ; in, , are detector pixel positions.

[0031] like Figure 3 As shown, the number of rows and columns of the matrix corresponds to the pixel coordinates on the detector target surface, and each element value in the matrix represents the wavelength value of the corresponding position.

[0032] Step S4, calibrating and optimizing the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer based on the standard light source to obtain the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0033] Therefore, in order to solve the problem that the spectrum restoration model of the echelle grating spectrometer is often based on the air medium ( ) design, and also took into account that the detection range of the spectrometer covers the far ultraviolet band, and high-pressure inert gas is used as the spectrum transmission medium. When performing geometric optical calculations, the change in the refractive index of the light transmission medium is fully considered ( ), ensuring the accuracy of the imaging position calculation. In addition, in order to correct the aberration of the optical system, a correction lens is usually designed between the focusing mirror and the detector when designing the optical system of the spectral instrument. However, since the introduction of the correction lens will lead to a decrease in the accuracy of the imaging position calculation, in order to solve the above technical problems, this embodiment takes into account the influence of the correction lens, thereby improving the accuracy of the imaging position calculation.

[0034] Implementation method 2: This implementation method further limits the method for constructing a two-dimensional spectrum restoration model of a medium-step grating spectrometer described in implementation method 1. If the correction lens includes multiple lens groups, the light offset in the Y direction of the detector is specifically: ; in, To correct the lens contains multiple mirror groups, the light is offset in the Y direction of the detector, is the distance between the light and the center of the focusing lens in the Y direction, , , , , , and are all the offsets of the light in the Y direction. The medium and correction lens parameters that the light passes through in the Y direction are different, and the offsets are also different. and are all positive integers, and and Not equal to 1, 2, 3, 4 and 5, ≠ ; Then the light is offset in the X direction of the detector, specifically: ; in, To correct the lens, which contains multiple mirror groups, the light is offset in the X direction of the detector. is the distance between the light and the center of the focusing lens in the X direction, , , , , , and The offsets are all in the X direction. The offsets are different when the medium and correction lens parameters that the light passes through in the X direction are different.

[0035] In this embodiment, solving the , , , , , , , , , , , , and When calculating the refractive index of a medium, the principle of geometric optics is used and the change of the refractive index of the medium through which the light passes is considered.

[0036] The correction lens described in the first embodiment is designed to include one lens group. If you want to achieve a better effect of building a two-dimensional spectrum restoration model of the echelle grating spectrometer, the correction lens can be designed to include multiple lens groups during optical design. The specific process of building a two-dimensional spectrum restoration model of the echelle grating spectrometer is referred to the first embodiment. The correction lens is designed to include two lens groups, and multiple offsets are added when modeling in the X and Y directions, specifically: ; ; in, To correct the lens design, it contains two mirror groups and the offset when modeling in the Y direction. To correct the lens design, it consists of two mirror groups, and the offset when modeling in the X direction is: is the distance between the light and the center of the focusing lens in the Y direction, The distance between the light and the center of the focusing lens in the X direction, , , , and are all the offsets of the light in the Y direction. The medium and correction lens parameters that the light passes through in the Y direction are different, and the offsets are also different. , , , and The offsets are all in the X direction. The offsets are different when the medium and correction lens parameters that the light passes through in the X direction are different.

[0037] The correction lens is designed to include three lens groups, and multiple offsets are added when modeling in the X and Y directions, specifically: ; ; in, To correct the lens design, it contains three mirror groups and the offset when modeling in the Y direction is: To correct the lens design, it contains three mirror groups and the offset when modeling in the X direction. , , , , , and are all the offsets of the light in the Y direction. The medium and correction lens parameters that the light passes through in the Y direction are different, and the offsets are also different. , , , , , and The offsets are all in the X direction. The offsets are different when the medium and correction lens parameters that the light passes through in the X direction are different.

[0038] Implementation method 3: This implementation method further limits the method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in implementation method 1. The step S4 is to calibrate the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, and optimize the optical structure parameters in the two-dimensional spectrum restoration model, including the following steps: Step S401, obtaining the optical structure initialization parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer; The optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer include the medium refractive index, the grating incident angle, the prism vertex angle, the grating offset angle and the system focal length; Step S402, traversing the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer, and generating the fitting coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer; Step S403, based on the characteristic wavelength of the standard light source, respectively calculating the mean square error between the fitted coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer and the actual coordinate position; Step S404, determine whether the mean square error sum is minimum, if yes, execute step S405, if no, return to step S402; Step S405, completing the correction and optimization of the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0039] In this embodiment, in the step S4, the two-dimensional spectrum restoration model of the echelle grating spectrometer is calibrated based on the standard light source to optimize the optical structure parameters in the two-dimensional spectrum restoration model, including the following steps: Step S401, obtaining the optical structure initialization parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer; By analyzing the geometric relationship between the model imaging position and the detector pixel position, it is determined that the grating incident angle, prism vertex angle, grating offset angle and system focal length are the key factors affecting the accuracy of the two-dimensional spectrum restoration model of the medium-step grating spectrometer. At the same time, since the implementation method uses high-pressure inert gas as the light transmission medium, the refractive index of the medium inside the instrument changes, and the influence of the refractive index of the medium must be considered in the correction method. For this reason, this implementation method selects these five parameters as the correction optimization parameters.

[0040] Step S402, traversing the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer, and generating the fitting coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer; The grid search method is used to change the input values ​​of medium refractive index, grating incident angle, prism vertex angle, grating offset angle and system focal length in turn, thereby obtaining a series of fitting coordinate positions of the two-dimensional spectrum restoration model of the medium-step grating spectrometer.

[0041] Step S403, based on the characteristic wavelength of the standard light source, respectively calculating the mean square error between the fitted coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer and the actual coordinate position; The mean square error and To evaluate the fitness of the model.

[0042] Mean square error and The expression is: ; in, is the number of selected characteristic spectra, is the actual horizontal coordinate of the characteristic spectrum, is the actual ordinate of the characteristic spectrum, Calculate the horizontal coordinate for the characteristic spectrum model, Calculate the ordinate for the characteristic spectral model.

[0043] Step S404, determine whether the mean square error sum is minimum, if yes, execute step S405, if no, return to step S402; Step S405, completing the correction and optimization of the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0044] When the mean square error and When the minimum value is reached, the corresponding medium refractive index, grating incident angle, prism apex angle, grating offset angle and system focal length are the optimal parameters of the two-dimensional spectrum restoration model of the medium-step grating spectrometer, thus completing the optimization of the optical structure parameters.

[0045] Therefore, this embodiment calibrates the two-dimensional spectrum restoration model of the medium-step grating spectrometer by adopting a grid search method, optimizes the parameters of the medium refractive index, grating incident angle, prism vertex angle, grating offset angle and system focal length in the two-dimensional spectrum restoration model of the medium-step grating spectrometer, thereby improving the accuracy and reliability of the two-dimensional spectrum restoration model of the medium-step grating spectrometer.

[0046] In order to better illustrate the method for constructing a two-dimensional spectrum restoration model of an echelon grating spectrometer described in this embodiment, a detailed description is given through the following examples: like Figure 4 As shown in the figure, when the optical structure parameters in the two-dimensional spectrum restoration model of the medium-step grating spectrometer are not optimized, the result of the offset of the characteristic spectrum of the standard light source in the X and Y directions is shown in the figure. The horizontal axis is the wavelength in nm, and the vertical axis is the deviation in pixel. It can be seen that the result error of the offset in the X and Y directions is large, such as Figure 5 As shown, when the optical structure parameters in the two-dimensional spectrum restoration model of the medium-step grating spectrometer have been optimized, the result of the offset of the characteristic spectrum of the standard light source in the X and Y directions is shown in Figure 1. The horizontal axis is the wavelength in nm, and the vertical axis is the deviation in pixel. It can be seen that the error of the offset in the X and Y directions is significantly reduced.

[0047] Embodiment 4: This embodiment further limits the method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer described in Embodiment 1, and includes the following modules: The first module is to establish the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium when the light passes through it; The second module is to establish the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; A construction module is constructed to construct a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; The calibration optimization module calibrates the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizes the optical structure parameters in the two-dimensional spectrum restoration model, and obtains the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

[0048] The above is a detailed introduction to the method and system for constructing a two-dimensional spectrum restoration model of a medium-step grating spectrometer proposed in the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for restoring a two-dimensional spectrum of an echelle grating spectrometer is constructed, characterized in that: The following steps are involved: Step S1, by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes, the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel is established; Step S2, establishing the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel by using the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; Step S3, constructing a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; Step S4, calibrating the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizing the optical structure parameters in the two-dimensional spectrum restoration model, and obtaining the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

2. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 1, characterized in that: In the step S1, the consideration of the change in the refractive index of the medium through which the light passes is to introduce the refractive index parameter of the light transmission gas medium.

3. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 1, characterized in that: In the step S1, the relationship between the wavelength of the echelle grating diffraction in the Y direction and the position of the detector pixel is established as follows: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the Y direction of the echelle grating diffraction, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the Y direction of the echelle grating diffraction, and the offset of the light in the Y direction of the detector is obtained.

4. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 3, characterized in that: The light offset in the Y direction of the detector is specifically: ； in, is the offset of the light in the Y direction of the detector, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, To correct the distance from the rear surface of the lens to the detector, is the angle between the light ray and the optical axis.

5. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 1, characterized in that: In the step S2, the relationship between the prism dispersion wavelength in the X direction and the detector pixel position is established as follows: When establishing a two-dimensional spectrum restoration model of the echelle grating spectrometer in the X direction of prism dispersion, the offset of the light caused by the correction lens set between the focusing mirror and the detector is calculated based on the wavelength of the incident light in the X direction of prism dispersion, and the offset of the light in the X direction of the detector is obtained.

6. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 5, characterized in that: The light offset in the detector X direction is specifically: ； in, is the offset of the light in the detector X direction, is the distance from the intersection of the light passing through the correction lens and the rear surface to the intersection of the optical axis, is the distance from the focusing lens to the front surface of the correction lens, To correct for the thickness of the lens, To correct the distance from the rear surface of the lens to the detector, is the distance from the intersection of the front surface of the correction lens and the optical axis to the center of the focusing lens, is the distance from the intersection of the front surface of the correction lens and the optical axis to the intersection of the back surface of the correction lens and the optical axis. is the angle between the light ray and the optical axis.

7. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 3 or 5, characterized in that: If the correction lens comprises multiple lens groups, the light offset in the Y direction of the detector is specifically: ； in, To correct the lens contains multiple mirror groups, the light is offset in the Y direction of the detector, is the distance between the light and the center of the focusing lens in the Y direction, , , , , , and are all the offsets of the light in the Y direction. The medium and correction lens parameters that the light passes through in the Y direction are different, and the offsets are also different. and are all positive integers, and and Not equal to 1, 2, 3, 4 and 5, ≠ ; Then the light is offset in the X direction of the detector, specifically: ； in, To correct the lens, which contains multiple mirror groups, the light is offset in the X direction of the detector. The distance between the light and the center of the focusing lens in the X direction, , , , , , and The offsets are all in the X direction. The offsets are different when the medium and correction lens parameters that the light passes through in the X direction are different.

8. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 7, characterized in that: Solve the , , , , , , , , , , , , and When calculating the refractive index of a medium, the principle of geometric optics is used and the change of the refractive index of the medium through which the light passes is considered.

9. The method for constructing a two-dimensional spectrum restoration model of an echelle grating spectrometer according to claim 1, characterized in that: The step S4, calibrating the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, and optimizing the optical structure parameters in the two-dimensional spectrum restoration model, comprises the following steps: Step S401, obtaining the optical structure initialization parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer; The optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer include the medium refractive index, the grating incident angle, the prism vertex angle, the grating offset angle and the system focal length; Step S402, traversing the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer, and generating the fitting coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer; Step S403, based on the characteristic wavelength of the standard light source, respectively calculating the mean square error between the fitted coordinate position of the two-dimensional spectrum restoration model of the echelle grating spectrometer and the actual coordinate position; Step S404, determine whether the mean square error sum is minimum, if yes, execute step S405, if no, return to step S402; Step S405, completing the correction and optimization of the optical structure parameters in the constructed two-dimensional spectrum restoration model of the echelle grating spectrometer.

10. Construct a two-dimensional spectrum restoration model system of a medium-step grating spectrometer, characterized in that: Includes the following modules: The first module is to establish the relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; The second module is to establish the relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel through the principle of geometric optics and taking into account the change in the refractive index of the medium through which the light passes; A construction module is constructed to construct a two-dimensional spectrum restoration model of the echelle grating spectrometer based on the established relationship between the wavelength in the Y direction of the echelle grating diffraction and the position of the detector pixel, and the established relationship between the wavelength in the X direction of the prism dispersion and the position of the detector pixel; The calibration optimization module calibrates the two-dimensional spectrum restoration model of the echelle grating spectrometer based on a standard light source, optimizes the optical structure parameters in the two-dimensional spectrum restoration model, and obtains the optimal two-dimensional spectrum restoration model of the echelle grating spectrometer.

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