CN116661138B - Optical design method of grating spectrometer - Google Patents

Optical design method of grating spectrometer Download PDF

Info

Publication number
CN116661138B
CN116661138B CN202310686263.1A CN202310686263A CN116661138B CN 116661138 B CN116661138 B CN 116661138B CN 202310686263 A CN202310686263 A CN 202310686263A CN 116661138 B CN116661138 B CN 116661138B
Authority
CN
China
Prior art keywords
grating
sampling
design
reconstruction
light
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202310686263.1A
Other languages
Chinese (zh)
Other versions
CN116661138A (en
Inventor
李文昊
王新宇
姜岩秀
郑钟铭
迟振东
郭灏锋
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Changchun Institute of Optics Fine Mechanics and Physics of CAS
Original Assignee
Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Changchun Institute of Optics Fine Mechanics and Physics of CAS filed Critical Changchun Institute of Optics Fine Mechanics and Physics of CAS
Priority to CN202310686263.1A priority Critical patent/CN116661138B/en
Publication of CN116661138A publication Critical patent/CN116661138A/en
Application granted granted Critical
Publication of CN116661138B publication Critical patent/CN116661138B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/0012Optical design, e.g. procedures, algorithms, optimisation routines

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Spectrometry And Color Measurement (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

The invention relates to the technical field of optical design, in particular to an optical design method of a grating spectrometer, which comprises the following steps: s1, generating an initial parent population; s2, generating a child population based on the initial parent population cross variation; the cross variation comprises sampling characteristic rays, and assigning a value to each sampling ray; s3, performing system reconstruction based on the offspring population; the system reconstruction comprises at least one of reticle distribution reconstruction, record structure reconstruction and grating surface type reconstruction; s4, carrying out optimization iterative design by using a genetic algorithm, and judging and selecting a new round of parent population based on the system reconstruction; the design method does not need to construct a complex aberration unfolding model, and reduces the manpower work of designers; the problem of high-order expansion neglect does not exist in the whole design process, and the design result is more accurate; can be designed according to any type of spectrometer, and the design is more universal.

Description

Optical design method of grating spectrometer
Technical Field
The present invention relates to the field of optical design technology, and in particular, to an optical design method for a grating spectrometer, a computer device capable of executing the method, and a computer-readable storage medium.
Background
The spectrometer can realize the accurate analysis of the wavelength-energy ratio of the complex-color light beam, and has wide application in the fields of metal smelting, biochemical analysis, environmental monitoring, component identification and the like. The grating spectrometer has the advantages of linear dispersion, high diffraction efficiency and the like, so that the grating spectrometer is widely applied to various spectrometers as a core light splitting element. The spectrometer type taking the grating as a core light splitting original mainly comprises CT and cross CT structure spectrometers which use plane gratings, rowland round structure and III type IV type grating spectrometer structures which use concave gratings, offner structure imaging spectrometers which use convex gratings and free-form surface grating spectrometers which are used in special fields; several exemplary spectrometer system configurations are shown in fig. 1-3, respectively.
For the design of a spectrometer, the traditional method is to construct an aberration model for a target system, generally, vector aberration theory, optical path function aberration theory and other methods are used, and the aberration coefficient in the constructed aberration model is optimally designed in cooperation with an optimization algorithm. Because the aberration models need to be ignored for a certain expansion term in the construction process, inherent expansion residual errors exist between the models and the real light paths, and the final design result is different from the true result, so that further analysis and verification are needed; meanwhile, the design method also puts forward the requirements on the design experience of the designer, and the accumulated design experience of the designer can help the design process to obtain the design result meeting the design index more quickly and efficiently. However, with the higher index requirement of spectral resolution and the new spectrometer structure with different purposes, the conventional design method inevitably has the problems of long design period, large design difficulty and the like when solving the brand new problems. Therefore, efficient and rapid design methods for grating spectrometers are necessary for the development of higher performance spectrometers.
Aiming at the design of the grating spectrometer, various researches are carried out at home and abroad, and various solutions are proposed:
Paper ANALYTICAL REPRESENTATION OF SPOT DIAGRAMS AND ITS application to THE DESIGN of monochromators presents a typical method for designing a concave grating spectrometer by using optical path function aberration theory, and implementing spectrometer design by constructing an aberration model of a system and optimizing system parameters. The method selectively ignores higher-order terms in the aberration expansion model when constructing the aberration expansion model, so that the final design result is different from the actual tracking result, and the design accuracy is low.
The paper "aberration-eliminating design thought of convex mother grating of flat-field concave grating for spectrometer" gives a method for realizing concave grating spectrometer by designing recording structure, and the aberration model is also used for optimization.
The paper 'astigmatism elimination design of a variable-pitch convex grating imaging spectrometer' proposes a design method based on a collective ray tracing analysis point column diagram and a gradient descent method for calculating the reticle distribution of a convex variable-pitch grating, and the tracing method has no unfolding residual error; however, a plurality of sampling wavelengths are required to be selected, corresponding weight factors are given, and the weights are repeatedly adjusted according to the design result in the whole design process, so that the optimization of the full field of view and the full wave band cannot be realized.
Paper Imaging spectrometer WITH SINGLE component of freeformconcave grating shows a design method of a free-form surface grating spectrometer, adopts a ray tracing means to reconstruct grating surface type and reticle distribution, but does not carry out optimizing design on spectrometer system parameters, and lacks a balanced optimizing design strategy for the performance in a complete working view field and a wave band.
Disclosure of Invention
The invention aims to solve the problems, and provides an optical design method of a grating spectrometer using an optical line tracking means as a core, which realizes rapid and efficient grating spectrometer design by reversely deducing and reconstructing grating characteristics from a spectrometer structure.
The invention provides an optical design method of a grating spectrometer, which comprises the following steps:
S1, generating an initial parent population by setting a system parameter optimizing center and a system parameter optimizing range;
S2, generating a child population based on the initial parent population cross variation; the cross variation comprises sampling characteristic light rays, and assigning a random wavelength and a random view field to each sampled light ray;
s3, performing system reconstruction based on the offspring population; the system reconstruction comprises at least one of reticle distribution reconstruction, record structure reconstruction and grating surface type reconstruction;
S4, carrying out optimization iterative design by using a genetic algorithm, and judging and selecting a new round of parent population based on the system reconstruction;
If the parent population does not meet the design target, replacing the initial parent population with the parent population, and circularly executing S2-S4 for iteration until the parent population meets the design target, and outputting a design result;
And if the parent population meets the design target, ending iteration and outputting a design result.
In some embodiments, the system parameters include operating band, operating field of view, and caliber parameters; the assignment includes assigning a random field of view, assigning a wavelength, assigning a caliber, and assigning a weight factor.
In some embodiments, the generating the initial parent population includes setting a population number, setting an optimization strategy, and setting an iterative control.
In some embodiments, the system reconstruction is a reticle distribution reconstruction, the system reconstruction comprising the steps of:
S311, randomly sampling a plurality of characteristic points on an incident slit of the grating spectrometer, and assigning random wavelengths and characteristic point positions on a grating surface; determining corresponding image point coordinates of the sampling feature points on the image plane according to the ideal object-image relationship;
S312, solving the incidence direction, the diffraction direction and the optical path of the sampling light on the sampling characteristic points of the grating surface according to the coordinate points of the sampling light obtained in S311 on the light source surface, the grating surface and the image surface; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line function and line density distribution of the sampling feature points of the corresponding grating surface according to a diffraction equation;
s313, fitting the data of the line function and the line density distribution obtained in the S312 by using a least square method, and obtaining a line distribution expression of the target grating through the fitting;
in the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the fitting residual error of the line data is minimized through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
In some embodiments, the system reconstruction is a recording structure reconstruction, the system reconstruction comprising the steps of:
S321, solving the incidence direction, the diffraction direction and the optical path of the sampling light on the sampling points of the grating surface at the coordinate points of the sampling light on the light source surface, the grating surface and the image surface; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line-scribing function and line-scribing density distribution of a sampling point of a corresponding grating surface according to a diffraction equation;
s322, on the premise that the position of a single recording light source point is known, calculating the light path length and direction information from a known exposure arm to a grating surface sampling characteristic point;
S323, solving the corresponding relative optical path difference and the light incidence direction of each sampling characteristic point on the grating surface in an unknown recording arm, statistically analyzing the corresponding recording arm length, and determining an angle parameter by combining the angle and the recording wavelength of the known recording arm with the equivalent grating density at the center;
in the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the distribution error of the recorded light source points at the corresponding position obtained by solving each sampling characteristic point in the S323 is minimized through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
In some embodiments, the system reconstruction is a grating-plane-type reconstruction, the system reconstruction comprising the steps of:
S331, determining a series of characteristic points, corresponding caliber sampling points and wavelengths on the slit according to a random sampling method; according to the ideal object-image relationship, determining the corresponding image point coordinates of each slit sampling characteristic point on the image plane;
S332, solving the optical path information of the reference light which has the same field of view and the same wavelength as those in S331 and passes through the center point of the unknown grating; solving the intersection point of the sampling light and the unknown grating surface in the S331, so that the optical path of the sampling light is consistent with the optical path of the corresponding reference light;
S333, solving the corresponding normal direction according to the diffraction equation aiming at the sampling characteristic points obtained in the S331, and obtaining a surface shape by using least square fitting;
In the step S4, performing the optimization iterative design using the genetic algorithm includes: minimizing the peak-valley value or root mean square value of the surface fitting residual error through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
In some embodiments, the fitting residual error for any round is additionally fitted to a polynomial as follows:
Wherein F weight represents a weight function for subsequent least squares fitting, a ijmn represents a fitting coefficient result, lambda is a wavelength, field is a field of view, and x aperture and z aperture represent caliber coordinates; i. j, m and n are fitting power numbers with non-negative integers, and 0< i+j+m+n is less than or equal to 3.
In some embodiments, the polynomial is used as a weight coefficient of the next round of fitting process to participate in the least square fitting.
The present invention also provides a computer device comprising:
at least one processor; and
A memory communicatively coupled to the at least one processor; wherein,
The memory stores instructions executable by the at least one processor to enable the at least one processor to perform a method of optical design of a grating spectrometer according to the present invention.
The present invention also provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to perform a method of optical design of a grating spectrometer according to the present invention.
Compared with the prior art, the invention has the following beneficial effects:
According to the optical design method of the grating spectrometer, a complex aberration unfolding model is not required to be constructed, and the manpower work of a designer is reduced; the problem of high-order expansion neglect does not exist in the whole design process, and the design result is more accurate; the design can be developed aiming at any type of spectrometer, and the design is more universal; the genetic algorithm is adopted to carry out global optimization, so that a more proper design result can be searched; moreover, a plurality of different design strategies can be freely selected, and the design difficulty and the design time can be further reduced by selecting different design strategies according to different design requirements.
Drawings
FIG. 1 is a schematic diagram of an Offner convex grating imaging spectrometer of the prior art;
FIG. 2 is a schematic diagram of a prior art concave grating spectrometer type III containing a grating recording structure;
FIG. 3 is a schematic diagram of a prior art echelle grating spectrometer using a free-form surface grating as the second order dispersive element;
FIG. 4 is a schematic diagram of the grating spectrometer composition and structure and a schematic diagram of the grating recording structure according to the embodiment of the present invention;
FIG. 5 is a schematic process diagram of a first system reconstruction method in accordance with an embodiment of the present invention;
FIG. 6 is a schematic process diagram of a second system reconstruction method in accordance with an embodiment of the present invention;
FIG. 7 is a schematic process diagram of a third system reconstruction method according to an embodiment of the present invention;
FIG. 8 is a flow chart of a method of optical design of a grating spectrometer in accordance with an embodiment of the present invention;
FIG. 9 is a block diagram of an exemplary computer device suitable for use in implementing embodiments of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limiting the invention.
In general, in a grating spectrometer system, light emitted from a light source surface is irradiated onto a grating surface through a plurality of optical elements (or directly), and light with different wavelengths after passing through the grating is diffracted into different directions in space and is converged on an image surface of the system through a plurality of subsequent original elements (or directly). In the embodiment of the present invention, as shown in fig. 4, the entire grating spectrometer system is divided into a front part, a grating part and a rear part, wherein the front part is from the light source to the front part of the grating, and the rear part includes from the rear part of the grating to the image plane.
As shown in fig. 4, for a light ray emitted from any point a on the light source surface, the light ray passes through a point P on the grating and then intersects with the phase surface at a point B, where C and D represent two exposure light source positions, and N represents a surface normal direction at the point P on the grating; fig. 4 is a graph representing a grating surface ray trace calculation in combination with an exposure system, whose optical path function can be represented by equation (1),
F=AP+PB+nPmλ (1)
Wherein n P represents the value of the reticle function at the point P of the grating, λ represents the calculated light wavelength, and m is the diffraction order of the grating; according to the fermat principle, the propagation path of the light is an optical path extremum, that is, the partial derivative of the optical path function F with respect to the P-point coordinate should be 0, specifically as shown in the formula (2) and the formula (3),
In the recording structure of the double spherical wave hologram grating shown in fig. 4, the line function and the line density function of the grating can be expressed as shown in equations (4) to (6),
λ0nP=(CP-DP)-(CO-DO) (4)
In the above formula, CP and DP represent the optical path from two light source points C and D to any point P on the grating surface, CO and DO represent the optical path from the light source point to the center of the grating, and δ represents the sign of solving the partial derivative; alpha, beta, gamma represent the directional cosine of the light of the corresponding angle mark, x, y, z represent the space coordinates of the corresponding angle mark, and lambda 0 represents the recording wavelength of the holographic grating; in other embodiments, where other grating recording structures are used, equations (5) and (6) are equally applicable without any modification.
In the specific embodiment of the present invention, according to the above calculation process, parameters mainly used for determining the propagation path of light on the grating of the calculation spectrometer can be classified into the following three types: the incidence direction and diffraction direction of the light, the grating surface shape and the reticle distribution of the grating (or the recording structure of the grating). When any two of these three types of quantities are known, the third set of quantities can be solved by the above derivation, and the present invention proposes the following specific embodiments based on this core idea.
Referring to fig. 8, which is a schematic flow chart of an optical design method of a grating spectrometer according to an embodiment of the present invention, it can be seen from the figure that in the embodiment of the present invention, an optical design method of a grating spectrometer is provided, and the optical design method includes the steps of:
S1, generating an initial parent population by setting a system parameter optimizing center and a system parameter optimizing range; the system parameters comprise working wave bands, working view fields and caliber parameters; the generation of the initial parent population comprises the steps of setting the population quantity, setting an optimization strategy and setting iterative control;
S2, generating a child population based on the initial parent population cross variation; the cross variation comprises sampling characteristic light rays, and assigning a random wavelength and a random view field to each sampling light ray; the assignment comprises the assignment of a random view field, the assignment of a random wavelength, the assignment of an assignment caliber and the assignment of a weight factor;
s3, performing system reconstruction based on the offspring population; the system reconstruction comprises a reticle distribution reconstruction, a recording structure reconstruction and a grating surface type reconstruction;
S4, carrying out optimization iterative design by using a genetic algorithm, and judging and selecting a new round of parent population based on the system reconstruction;
If the parent population does not meet the design target, replacing the initial parent population with the parent population, and circularly executing S2-S4 for iteration until the parent population meets the design target, and outputting a design result;
And if the parent population meets the design target, ending iteration and outputting a design result.
In a specific embodiment, the design result is output through iterative convergence of a genetic algorithm; specifically, two control strategies are included, when any one of the two control strategies meets any condition, the calculation result is considered to be converged, and iteration can be ended; in the first mode, the number of iteration rounds reaches the set maximum number of iteration rounds, the maximum number of iteration rounds can be manually adjusted, and 20 rounds can be selected preferably; in a second way, the iteration decision function value reaches a preset minimum result, and in particular, the result is different according to the system reconstruction strategy corresponding to the three different embodiments related to the present invention.
The optical design method of the grating spectrometer provided by the specific embodiment of the invention is a grating spectrometer design method based on a ray tracing method, and can avoid the problems of poor design precision and long design period caused by the traditional aberration model unfolding method; by using the correlation between the light direction, the grating surface shape and the grating line distribution in the grating diffraction process, the spectrometer design is realized by solving the position parameters under the condition that any two types of data are known.
According to the optical design method of the grating spectrometer, when a genetic algorithm is used for optimally designing a design process, a random view field, wavelength and caliber sampling mode is used, and each round of iterative process uses a completely random sampling result, so that the design result is guaranteed to have balanced high resolution of a continuous view field and a continuous wave band; meanwhile, solving an unknown design parameter by using a fitting mode, and taking a peak-to-valley value or a root mean square value of a fitting residual error as a judgment; in the iterative design process, using a polynomial of fitting residual errors of a previous round of design targets relative to a field of view, wavelength and sampling caliber as a weight factor of a next round of design to guide the design process of the next round; during the score line distribution fitting and the surface type fitting, the score line function value (or the surface type vector high value) and the score line function density value (or the surface type partial derivative value) are simultaneously used for fitting, so that the fitting result is ensured to be closer to the design target; aberration tolerant designs can be achieved by altering the starting point (i.e., image point) of the back-trace in the spectrometer system; moreover, the process is automatically changed through the tracking result, so that the human participation is reduced.
In a first specific embodiment, the system reconstruction may be a reticle distribution reconstruction, the system reconstruction comprising the steps of:
S311, randomly sampling a plurality of characteristic points on an incident slit of the grating spectrometer, and assigning random wavelengths and characteristic point positions on a grating surface; determining corresponding image point coordinates of the sampling feature points on the image plane according to the ideal object-image relationship;
S312, solving the incidence direction, the diffraction direction and the optical path of the sampling light on the sampling characteristic points of the grating surface according to the coordinate points of the sampling light obtained in S311 on the light source surface, the grating surface and the image surface; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line function and line density distribution of the sampling feature points of the corresponding grating surface according to a diffraction equation;
s313, fitting the data of the line function and the line density distribution obtained in the S312 by using a least square method, and obtaining a line distribution expression of the target grating through the fitting;
in the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the fitting residual error of the line data is minimized through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
Referring specifically to fig. 5, which is a schematic process diagram of a first system reconstruction method in a specific embodiment of the present invention, taking the convex aberration-eliminating grating Offner imaging spectrometer shown in fig. 1 as an example, the purpose of system reconstruction is to obtain a target grating reticle distribution model satisfying the current structure, that is, each of coefficients n 0,n1,n2 and n 3 of the reticle function in equation (7),
n=n0+n1z+n2z2+n3z3 (7)
The formula (7) is to obtain a target grating line density distribution model in a fourth-order polynomial form; the specific design process comprises the following steps:
(0) Assuming that the positions and attitudes of the various elements (including entrance slit, 1,3 mirrors, convex grating and phase plane) in the system are all determined, the face type of the various optical elements is also determined;
(1) Randomly sampling a plurality of characteristic points on the incident slit, and assigning random wavelength and characteristic point positions on the grating surface; determining corresponding image point coordinates of the characteristic points on an image plane according to the ideal object-image relationship;
(2) Aiming at coordinate points of the sampling light rays in the step (1) on a light source surface, a grating surface and an image surface, solving the incidence direction, the diffraction direction and the optical path of the sampling light rays on the grating surface sampling points according to a reflection law, and simultaneously solving the optical path of the light rays which have the same field of view and wavelength but pass through the center of a system aperture diaphragm; calculating a line-scribing function and line-scribing density distribution of sampling points on a corresponding grating surface according to a diffraction equation;
(3) Fitting the score line function and the score line density data obtained in the step (2) by using a least square method, wherein the fitting target is to obtain a target grating score line distribution expression;
(4) Carrying out optimization solving on the process by using a genetic algorithm, wherein the solving aim is to enable the fitting residual error of the score line data to have the minimum peak-valley value or root mean square; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, namely, each round of iteration uses different light source plane coordinates, grating plane coordinates and corresponding wavelengths, so that the design result is guaranteed to have balanced resolving power in a continuous view field and a continuous wave band.
In a second embodiment, the system reconstruction is a recording structure reconstruction, the system reconstruction comprising the steps of:
S321, solving the incidence direction, the diffraction direction and the optical path of the sampling light on the sampling points of the grating surface at the coordinate points of the sampling light on the light source surface, the grating surface and the image surface; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line-scribing function and line-scribing density distribution of a sampling point of a corresponding grating surface according to a diffraction equation;
s322, on the premise that the position of a single recording light source point is known, calculating the light path length and direction information from a known exposure arm to a grating surface sampling characteristic point;
S323, solving the corresponding relative optical path difference and the light incidence direction of each sampling characteristic point on the grating surface in an unknown recording arm, statistically analyzing the corresponding recording arm length, and determining an angle parameter by combining the angle and the recording wavelength of the known recording arm with the equivalent grating density at the center;
in the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the distribution error of the recorded light source points at the corresponding position obtained by solving each sampling characteristic point in the S323 is minimized through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
Referring to fig. 6, which is a schematic process diagram of a second system reconstruction method in a specific embodiment of the present invention, taking a type iii concave grating flat field spectrometer shown in fig. 2 as an example, the specific steps include:
(0) Assuming that the spectrometer structure (including the incident slit, the positions of the grating and the image plane and the curvature radius of the grating substrate) is known, determining a series of characteristic points on the slit, corresponding grating sampling points and wavelengths according to a random sampling method, and determining an image point of each slit sampling point on the image plane according to an ideal object-image relationship; while assuming that any one of the light source positions (assumed to be C) in the grating recording structure is known;
(1) Obtaining a reticle function value and a reticle function density value of sampling points on a grating surface according to the same logic in solving the reticle distribution;
(2) On the premise of knowing the position of a single recording light source point, calculating the light path length and direction information from a known exposure arm to a grating surface sampling characteristic point;
(3) According to the aforementioned formula (5) and formula (6), solving the corresponding relative optical path difference and light incidence direction of each sampling characteristic point on the grating surface in the unknown recording arm, and statistically analyzing the corresponding recording arm length, wherein the angle parameter can be determined by the equivalent grating density at the center and the known recording arm angle and the known recording wavelength:
(4) Optimally designing all the known parameters assumed in the process by using a genetic algorithm, wherein the optimization aim is to minimize the peak-valley value or root mean square value of the distribution error of the corresponding position record light source point obtained by solving each grating sampling point in the step (3); meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, namely, each round of iteration uses different light source plane coordinates, grating plane coordinates and corresponding wavelengths, so that the design result is guaranteed to have balanced resolving power in a continuous view field and a continuous wave band.
In a third specific embodiment, the system reconstruction is a grating surface type reconstruction, and the system reconstruction includes the steps of:
S331, determining a series of characteristic points, corresponding caliber sampling points and wavelengths on the slit according to a random sampling method; according to the ideal object-image relationship, determining the corresponding image point coordinates of each slit sampling characteristic point on the image plane;
S332, solving the optical path information of the reference light which has the same field of view and the same wavelength as those in S331 and passes through the center point of the unknown grating; solving the intersection point of the sampling light and the unknown grating surface in the S331, so that the optical path of the sampling light is consistent with the optical path of the corresponding reference light;
S333, solving the corresponding normal direction according to the diffraction equation aiming at the sampling characteristic points obtained in the S331, and obtaining a surface shape by using least square fitting;
In the step S4, performing the optimization iterative design using the genetic algorithm includes: minimizing the peak-valley value or root mean square value of the surface fitting residual error through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
Referring to fig. 7, which is a schematic diagram illustrating a process of a third system reconstruction method in a specific embodiment of the present invention, taking the free-form surface grating spectrometer shown in fig. 3 as an example, the method for solving the basal plane type of the free-form surface grating, although the first system reconstruction method and the second system reconstruction method can still be used in designing the grating spectrometer, the method for converting the solving target from the reticle distribution to the grating plane type can effectively reduce the design difficulty; the method comprises the following specific steps:
(0) Assuming that other parameters except the target grating surface type are known in the whole spectrometer system, including the positions of all elements, the surface types of other elements, a grating line distribution model and the like; determining characteristic points on a series of slits, corresponding caliber sampling points and wavelengths according to a random sampling method, and determining image points of each slit sampling point on an image plane according to an ideal object-image relationship;
(1) Solving the reference light path information which has the same field of view and wavelength sampling as in the step (0) but passes through the center point of the unknown grating; taking the intersection point of the sampling characteristic light and the unknown grating surface in the step (0) of solving the reference, so that the optical path length of the sampling light is consistent with the optical path length of the corresponding reference light;
(2) Solving the corresponding normal direction for the characteristic points obtained in the step (1) according to a diffraction equation, and obtaining a surface model by using least square fitting;
(3) Optimally designing all unknown parameters which are supposed to be known in the process by using a genetic algorithm, wherein the optimization target is to minimize the peak-valley value or root mean square value of the surface type fitting residual error; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, namely, each round of iteration uses different light source plane coordinates, grating plane coordinates and corresponding wavelengths, so that the design result is guaranteed to have balanced resolving power in a continuous view field and a continuous wave band.
In a specific embodiment, the first system reconstruction mode and the third system reconstruction mode relate to a fitting process, and the fitting residual error of any round is additionally fitted as shown in the following polynomial (7), specifically, a polynomial corresponding to the field of view, the caliber and the wavelength:
Wherein F weight represents a weight function for subsequent least squares fitting, a ijmn represents a fitting coefficient result, lambda is a wavelength, field is a field of view, and x aperture and z aperture represent caliber coordinates; i. j, m and n are fitting power numbers with non-negative integers, and 0< i+j+m+n is less than or equal to 3. The polynomial can be used as a weight coefficient of the next round of fitting process to participate in the least square fitting; this additional weight adjustment step can ensure the overall design results of the present invention, achieving balanced high resolution in the complete operating band and operating field of view.
In other embodiments, the above mentioned holographic grating recording structure may be replaced by a design in which a non-planar mirror is added in the exposure arm, in which case the method of the invention may be replaced in the design by a reconstruction process for the auxiliary mirror, respectively.
According to the optical design method of the grating spectrometer, a complex aberration unfolding model is not required to be constructed, and the manpower work of a designer is reduced; the problem of high-order expansion neglect does not exist in the whole design process, and the design result is more accurate; the design can be developed aiming at any type of spectrometer, and the design is more universal; the genetic algorithm is adopted to carry out global optimization, so that a more proper design result can be searched; moreover, a plurality of different design strategies can be freely selected, and the design difficulty and the design time can be further reduced by selecting different design strategies according to different design requirements.
Accordingly, the present invention also provides a computer device, a readable storage medium and a computer program product according to embodiments of the present invention.
Fig. 9 is a schematic structural diagram of a computer device 12 according to an embodiment of the present invention. Fig. 9 illustrates a block diagram of an exemplary computer device 12 suitable for use in implementing embodiments of the present invention. The computer device 12 shown in fig. 9 is merely an example and should not be construed as limiting the functionality and scope of use of embodiments of the present invention.
As shown in fig. 9, the computer device 12 is in the form of a general purpose computing device. Computer device 12 is intended to represent various forms of digital computers, such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device may also represent various forms of mobile devices, such as personal digital processing, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions, are meant to be exemplary only, and are not meant to limit implementations of the inventions described and/or claimed herein.
Components of computer device 12 may include, but are not limited to: one or more processors or processing units 16, a system memory 28, a bus 18 that connects the various system components, including the system memory 28 and the processing units 16.
Bus 18 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, micro channel architecture (MAC) bus, enhanced ISA bus, video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.
Computer device 12 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by computer device 12 and includes both volatile and nonvolatile media, removable and non-removable media.
The system memory 28 may include computer system readable media in the form of volatile memory, such as Random Access Memory (RAM) 30 and/or cache memory 32. The computer device 12 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, storage system 34 may be used to read from or write to non-removable, nonvolatile magnetic media (not shown in FIG. 9, commonly referred to as a "hard disk drive"). Although not shown in fig. 9, a magnetic disk drive for reading from and writing to a removable non-volatile magnetic disk (e.g., a "floppy disk"), and an optical disk drive for reading from or writing to a removable non-volatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In such cases, each drive may be coupled to bus 18 through one or more data medium interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to carry out the functions of embodiments of the invention.
A program/utility 40 having a set (at least one) of program modules 42 may be stored in, for example, memory 28, such program modules 42 including, but not limited to, an operating system, one or more application programs, other program modules, and program data, each or some combination of which may include an implementation of a network environment. Program modules 42 generally perform the functions and/or methods of the embodiments described herein.
The computer device 12 may also communicate with one or more external devices 14 (e.g., keyboard, pointing device, display 24, etc.), one or more devices that enable a user to interact with the computer device 12, and/or any devices (e.g., network card, modem, etc.) that enable the computer device 12 to communicate with one or more other computing devices. Such communication may occur through an input/output (I/O) interface 22. Moreover, computer device 12 may also communicate with one or more networks such as a Local Area Network (LAN), a Wide Area Network (WAN) and/or a public network, such as the Internet, through network adapter 20.
As shown in fig. 9, the network adapter 20 communicates with other modules of the computer device 12 via the bus 18. It should be appreciated that although not shown, other hardware and/or software modules may be used in connection with computer device 12, including, but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, data backup storage systems, and the like.
The processing unit 16 executes various functional applications and data processing by running programs stored in the system memory 28, for example, implementing the optical design method of the grating spectrometer provided by the embodiment of the present invention.
The embodiment of the application also provides a non-transitory computer readable storage medium storing computer instructions, and a computer program stored thereon, wherein the program is executed by a processor, and the optical design method of the grating spectrometer is provided by all the embodiments of the application.
The computer storage media of embodiments of the invention may take the form of any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. More specific examples (a non-exhaustive list) of the computer-readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.
The computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, either in baseband or as part of a carrier wave. Such a propagated data signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination of the foregoing. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations of the present invention may be written in one or more programming languages, including an object oriented programming language such as Java, smalltalk, C ++ and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any kind of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (for example, through the Internet using an Internet service provider).
The embodiments of the present invention also provide a computer program product comprising a computer program which, when executed by a processor, implements the optical design method of a grating spectrometer according to the above.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present disclosure may be performed in parallel, sequentially, or in a different order, provided that the desired results of the technical solutions of the present disclosure are achieved, and are not limited herein.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (7)

1. A method of optical design for a grating spectrometer, the method comprising the steps of:
S1, generating an initial parent population by setting a system parameter optimizing center and a system parameter optimizing range;
S2, generating a child population based on the initial parent population cross variation; the cross variation comprises sampling characteristic rays, and assigning a random wavelength and a random view field to each sampling characteristic ray;
S3, performing system reconstruction based on the offspring population; the system reconstruction comprises at least one of reticle distribution reconstruction, record structure reconstruction and grating surface type reconstruction; the system reconstruction is a reticle distribution reconstruction, and the system reconstruction comprises the following steps:
S311, randomly sampling a plurality of characteristic points on an incident slit of the grating spectrometer, and assigning random wavelengths and characteristic point positions on a grating surface; determining corresponding image point coordinates of the sampling feature points on the image plane according to the ideal object-image relationship;
S312, solving the incidence direction, the diffraction direction and the optical path of the sampling characteristic light rays on the sampling characteristic points of the grating surface according to the coordinate points of the sampling characteristic light rays on the light source surface, the grating surface and the image surface obtained in the S311; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line function and line density distribution of the sampling feature points of the corresponding grating surface according to a diffraction equation;
s313, fitting the data of the line function and the line density distribution obtained in the S312 by using a least square method, and obtaining a line distribution expression of the target grating through the fitting;
the system reconstruction is a recording structure reconstruction, the system reconstruction comprises the steps of:
S321, obtaining coordinate points of sampling characteristic light on a light source surface, a grating surface and an image surface, and solving the incidence direction, the diffraction direction and the optical path of the sampling characteristic light on the grating surface sampling point; meanwhile, solving the optical path of the light which has the same field of view and the same wavelength and passes through the center of the aperture diaphragm of the system; calculating a line-scribing function and line-scribing density distribution of a sampling point of a corresponding grating surface according to a diffraction equation;
s322, on the premise that the position of a single recording light source point is known, calculating the light path length and direction information from a known exposure arm to a grating surface sampling characteristic point;
s323, solving the corresponding relative optical path difference and the light incidence direction of each sampling characteristic point on the grating surface in an unknown recording arm, statistically analyzing the corresponding recording arm length, and determining an angle parameter by combining the angle and the recording wavelength of the known recording arm with the equivalent grating line density at the center;
the system reconstruction is a grating surface type reconstruction, and the system reconstruction comprises the following steps:
S331, determining a series of characteristic points, corresponding caliber sampling points and wavelengths on the slit according to a random sampling method; according to the ideal object-image relationship, determining the corresponding image point coordinates of each slit sampling characteristic point on the image plane;
S332, solving the optical path information of the reference light which has the same field of view and the same wavelength as those in S331 and passes through the center point of the unknown grating; solving the intersection point of the sampling characteristic light and the unknown grating surface in the S331, so that the optical path of the sampling characteristic light is consistent with the optical path of the corresponding reference light;
S333, solving the corresponding normal direction according to the diffraction equation aiming at the sampling characteristic points obtained in the S331, and obtaining a surface shape by using least square fitting;
S4, carrying out optimization iterative design by using a genetic algorithm, and judging and selecting a new round of parent population based on the system reconstruction;
If the parent population does not meet the design target, replacing the initial parent population with the parent population, and circularly executing S2-S4 for iteration until the parent population meets the design target, and outputting a design result;
Ending iteration if the parent population meets the design target, and outputting a design result;
In the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the fitting residual error of the line data is minimized through a genetic algorithm; simultaneously, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process;
In the step S4, performing the optimization iterative design using the genetic algorithm includes: minimizing the peak-valley value or root mean square value of the surface fitting residual error through a genetic algorithm; simultaneously, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process;
in the step S4, performing the optimization iterative design using the genetic algorithm includes: the peak-valley value or root mean square value of the distribution error of the recorded light source points at the corresponding position obtained by solving each sampling characteristic point in the S323 is minimized through a genetic algorithm; meanwhile, the sampling of the characteristic light is changed immediately in the iterative process of the genetic algorithm, and different light source plane coordinates, grating plane coordinates and corresponding wavelengths are used in each round of iterative process.
2. The method of optical design of a grating spectrometer according to claim 1, wherein the system parameters include operating band, operating field of view, and caliber parameters; the assigning includes assigning a random field of view, assigning a random wavelength, assigning a caliber, and assigning a weight factor.
3. The method of optical design of a grating spectrometer of claim 1, wherein generating the initial parent population comprises setting a population number, setting an optimization strategy, and setting an iterative control.
4. The optical design method of a grating spectrometer according to claim 1, wherein the fitting residual error of any round is additionally fitted to a polynomial as follows:
Wherein F weight represents a weight function for subsequent least squares fitting, a ijmn represents a fitting coefficient result, lambda is a wavelength, field is a field of view, and x aperture and z aperture represent caliber coordinates; i. j, m and n are fitting power numbers with non-negative integers, and 0< i+j+m+n is less than or equal to 3.
5. The optical design method of grating spectrometer according to claim 4, wherein the polynomial is used as the weight coefficient of the next round of fitting process to participate in the least square fitting.
6. A computer device, comprising:
at least one processor; and
A memory communicatively coupled to the at least one processor; wherein,
The memory stores instructions executable by the at least one processor to enable the at least one processor to perform the optical design method of the grating spectrometer of any one of claims 1 to 5.
7. A non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the optical design method of the grating spectrometer of any one of claims 1 to 5.
CN202310686263.1A 2023-06-09 2023-06-09 Optical design method of grating spectrometer Active CN116661138B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310686263.1A CN116661138B (en) 2023-06-09 2023-06-09 Optical design method of grating spectrometer

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310686263.1A CN116661138B (en) 2023-06-09 2023-06-09 Optical design method of grating spectrometer

Publications (2)

Publication Number Publication Date
CN116661138A CN116661138A (en) 2023-08-29
CN116661138B true CN116661138B (en) 2024-05-14

Family

ID=87727738

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310686263.1A Active CN116661138B (en) 2023-06-09 2023-06-09 Optical design method of grating spectrometer

Country Status (1)

Country Link
CN (1) CN116661138B (en)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997021979A1 (en) * 1995-12-12 1997-06-19 Spectral Diagnostic Ltd. Spectral bio-imaging methods for biological research, medical diagnostics and therapy
WO1999064829A1 (en) * 1998-06-12 1999-12-16 Varian, Inc. Fast automated spectral fitting method
CN104297829A (en) * 2014-09-30 2015-01-21 中国科学院长春光学精密机械与物理研究所 Method for optimum design of planar variable-pitch grating
CN110631700A (en) * 2019-08-29 2019-12-31 南京波思途智能科技股份有限公司 Spectrometer light path design method
CN112666698A (en) * 2021-01-27 2021-04-16 之江实验室 Dispersive super-surface-based fiber bundle multi-azimuth three-dimensional confocal imaging device and method
CN114440772A (en) * 2022-01-28 2022-05-06 合肥工业大学 Blazed transmission grating spectrometer
CN114877995A (en) * 2021-02-05 2022-08-09 清华大学 Design method of free-form surface concave grating imaging spectrometer

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9612155B2 (en) * 2004-03-20 2017-04-04 Electronic Photonic Ic Inc. (Epic Inc.) Curved grating spectrometer and wavelength multiplexer or demultiplexer with very high wavelength resolution

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997021979A1 (en) * 1995-12-12 1997-06-19 Spectral Diagnostic Ltd. Spectral bio-imaging methods for biological research, medical diagnostics and therapy
WO1999064829A1 (en) * 1998-06-12 1999-12-16 Varian, Inc. Fast automated spectral fitting method
CN104297829A (en) * 2014-09-30 2015-01-21 中国科学院长春光学精密机械与物理研究所 Method for optimum design of planar variable-pitch grating
CN110631700A (en) * 2019-08-29 2019-12-31 南京波思途智能科技股份有限公司 Spectrometer light path design method
CN112666698A (en) * 2021-01-27 2021-04-16 之江实验室 Dispersive super-surface-based fiber bundle multi-azimuth three-dimensional confocal imaging device and method
CN114877995A (en) * 2021-02-05 2022-08-09 清华大学 Design method of free-form surface concave grating imaging spectrometer
CN114440772A (en) * 2022-01-28 2022-05-06 合肥工业大学 Blazed transmission grating spectrometer

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
Computed-tomography imaging spectrometer: experimental calibration and reconstruction results;Michael Descour and Eustace Dereniak;《APPLIED OPTICS》;19950801;第34卷(第22期);全文 *
双光栅平场全息凹面光栅光谱仪的优化设计;孔鹏, 巴音贺希格, 李文昊;《光学学报》;20110228;第31卷(第2期);全文 *
变间距凸面光栅成像光谱系统的消像散设计;赵美红, 王新宇, 姜岩秀;《光学精密工程》;20201031;第28卷(第10期);全文 *

Also Published As

Publication number Publication date
CN116661138A (en) 2023-08-29

Similar Documents

Publication Publication Date Title
Jafrancesco et al. Optical simulation of a central receiver system: Comparison of different software tools
Duffie et al. Analytical value-at-risk with jumps and credit risk
Thomas et al. Mapping stationary axisymmetric phase-space distribution functions by orbit libraries
Liesenborgs et al. A genetic algorithm for the non‐parametric inversion of strong lensing systems
Dye et al. Herschel-ATLAS: modelling the first strong gravitational lenses
Bouchaud et al. A realistic two-dimensional model of Altair
Cobo et al. DeSIRe: Departure coefficient aided Stokes Inversion based on Response functions
Soltz et al. Constraining the initial temperature and shear viscosity in a hybrid hydrodynamic model of s N N= 200 GeV Au+ Au collisions using pion spectra, elliptic flow, and femtoscopic radii
CN111487766B (en) Design method of free-form surface off-axis three-mirror imaging system
Hess et al. Physically constrained generative adversarial networks for improving precipitation fields from Earth system models
Mangham et al. Do reverberation mapping analyses provide an accurate picture of the broad-line region?
US20040243364A1 (en) Method and system for modeling solar optics
CN112649179A (en) Method, system, computing device and storage medium for detecting blazed gratings
CN116661138B (en) Optical design method of grating spectrometer
CN110133844A (en) The design method of freeform optics system with Dispersive Devices
TW202232065A (en) Design method of an imaging spectrometer having a single freeform concave grating
JP5137039B2 (en) Thermal radiation energy simulation apparatus and method
CN117195332A (en) Method and device for designing optical system, and computer-readable storage medium
CN116661139B (en) Design method of free-form surface optical system
CN114818315A (en) Method and equipment for simulating and analyzing plane optical system based on linked list processing
CN109613697B (en) Design method of reflective aspheric optical system
Breault et al. Stray Light Analysiswith Apart/Pade. Version 8.7
CN111414572A (en) Method and device for cross certification of radio star watch and infrared star watch and readable storage medium
Nijkerk et al. Freeform optics design tool for compact spectrometers
Greynolds Stray light computations: Has nothing changed since the 1970s?

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant