CN115507947A - Wavelength calibration method for grating spectrometer - Google Patents
Wavelength calibration method for grating spectrometer Download PDFInfo
- Publication number
- CN115507947A CN115507947A CN202211015243.3A CN202211015243A CN115507947A CN 115507947 A CN115507947 A CN 115507947A CN 202211015243 A CN202211015243 A CN 202211015243A CN 115507947 A CN115507947 A CN 115507947A
- Authority
- CN
- China
- Prior art keywords
- wavelength
- grating
- calibration
- light source
- spectrometer
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 40
- 230000003595 spectral effect Effects 0.000 claims abstract description 29
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 claims description 7
- 229910052753 mercury Inorganic materials 0.000 claims description 7
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 9
- 238000004364 calculation method Methods 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 6
- 230000002349 favourable effect Effects 0.000 description 4
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 1
- BKZJXSDQOIUIIG-UHFFFAOYSA-N argon mercury Chemical compound [Ar].[Hg] BKZJXSDQOIUIIG-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/0297—Constructional arrangements for removing other types of optical noise or for performing calibration
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/02—Details
- G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
- G01J3/28—Investigating the spectrum
- G01J3/2803—Investigating the spectrum using photoelectric array detector
Landscapes
- Physics & Mathematics (AREA)
- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Spectrometry And Color Measurement (AREA)
Abstract
The application discloses a wavelength calibration method of a grating spectrometer, which comprises the following steps: establishing a functional relation between the peak value of the characteristic peak of the standard light source and the step number of a motor for controlling the angle of the grating; calculating the distance D between the falling point of the non-central wavelength irradiated on the multi-point detector and the falling point of the central wavelength; calculating the equivalent distance L between the multipoint detector and the grating; calculating the angular deviation alpha of the non-central wavelength and the central wavelength irradiated on the multi-point detector n (ii) a Calculating diffraction angle theta of non-central wavelength irradiated on multi-point detector n (ii) a Calculating the wavelength value lambda of the non-central wavelength irradiated on the multi-point detector n (ii) a And calculating the wavelength calibration coefficient of the spectrometer. This application compares with the mode that many calibration spectral lines of traditional adoption were calibrated, and this application only needs can accomplish the calibration to the spectrometer through a standard spectral lineThe calibration method has the advantages that the calibration steps are simplified, the complexity of the traditional calibration method is reduced, and the calibration efficiency is effectively improved on the premise of ensuring the accuracy of the calibration result.
Description
Technical Field
The application relates to the field of spectrum calibration, in particular to a wavelength calibration method of a grating spectrometer.
Background
The wavelength calibration of the linear array CCD spectrometer adopting the linear array CCD detector is realized by utilizing a standard light source with recognized characteristic spectral lines, obtaining the pixel position of each characteristic spectral peak of the standard light source from the linear array CCD spectrometer, determining the corresponding relation between the pixel position of the detector and the pixel position-wavelength of the wavelength by utilizing the wavelength of the known characteristic spectral peak and the pixel position of the characteristic spectral peak through methods of interpolation, fitting and the like, and finally determining the wavelength corresponding to each pixel of the detector.
The traditional calibration method mainly comprises the following steps: 1. the linear method: that is, the wavelength of the monochromatic light is considered to change according to a linear rule within a certain range. I.e., Δ λ/Δd (offset of the center wavelength of Δ d) is constant. Based on the raster equation, the smaller the value of Δ d, the smaller the deviation, and vice versa. Therefore, applying this method for calibration, the wavelength at the CCD edge will be inaccurate. 2. Polynomial fitting method: the common method for calibrating the wavelength of the spectrometer is to use a standard light source with recognized characteristic spectral lines, such as a mercury argon lamp, and the like, the spectrometer collects the radiation rays of the standard light source, the position of the characteristic spectral lines collected by the spectrometer is compared and matched with the recognized spectral lines, the wavelength calibration coefficient of the spectrometer is calculated through polynomial fitting, and the calibration coefficient reflects the corresponding relation between the wavelength and the pixel points of the spectrometer. This method requires that the characteristic peaks for calibration be distributed as uniformly as possible on the CCD surface, so that the accuracy of the calibration results can be ensured. Furthermore, after calibration in this way, the grating cannot be adjusted any more.
With respect to the related art among the above, there are the following drawbacks: in order to ensure the accuracy of the result, the conventional calibration method needs a plurality of calibration spectral lines to simultaneously appear on the CCD under the condition that the calibration spectral lines meet strict conditions, which results in tedious calibration.
Disclosure of Invention
In order to improve calibration efficiency on the premise of ensuring accurate calibration results, the application provides a wavelength calibration method for a grating spectrometer.
The wavelength calibration method for the grating spectrometer adopts the following technical scheme:
a wavelength calibration method of a grating spectrometer comprises the following steps:
s1, establishing a functional relation between a peak value of a characteristic peak of a standard light source and the number of steps of a motor for controlling the angle of a grating;
s2, a multi-point detector is arranged at a light outlet of the spectrometer, a standard light source irradiates the multi-point detector after passing through the spectrometer, and the distance D between a falling point of a characteristic peak of the standard light source irradiating the multi-point detector, which is positioned at a non-central wavelength, and a central wavelength falling point is calculated; the central wavelength is the wavelength vertical to the light outlet of the spectrometer;
s3, calculating the equivalent distance L between the multipoint detector and the grating through the functional relation; the equivalent distance L is the distance between the diffraction point at the center of the grating and the acquisition surface of the multi-point detector;
s4, according to the formula
Calculating the angular deviation alpha of the non-central wavelength and the central wavelength irradiated on the multi-point detector n ；
S5, diffraction angle theta according to central wavelength of standard light source 1 Calculating the diffraction angle theta of non-central wavelengths impinging on the multi-point detector n Comprises the following steps:
θ n ＝θ 1 -α n ；
s6, calculating the wavelength value lambda of the non-central wavelength irradiated on the multi-point detector according to a grating formula n Comprises the following steps:
λ n ＝dsinθ n /k；
and S7, calibrating according to the comparison and matching of the position of the characteristic spectral line acquired by the spectrometer and the recognized spectral line.
Through adopting above-mentioned technical scheme, compare with the traditional mode that adopts many calibration spectral lines to calibrate, this application only needs can accomplish the calibration to the spectrometer through 1 standard spectral line, has simplified the calibration step, has reduced the loaded down with trivial details nature that needs many standard spectral lines to calibrate to the spectrometer in traditional calibration method, has effectively improved calibration efficiency under the accurate prerequisite of assurance calibration result.
Optionally, the step S1 includes:
s10: and an exit slit is arranged at a light outlet of the spectrometer, and the central wavelength of the spectrometer is calibrated according to a calibration method of a monochromator.
S11: the exit slit is removed after calibration.
By adopting the technical scheme, the relationship between the central wavelength (the peak value of the characteristic peak) and the grating corner is established through the outlet slit, the calibration method of the outlet slit is easy to operate by personnel, the accuracy is high, and the calibration cost is effectively reduced on the premise of ensuring the calibration result.
Optionally, the equivalent distance L is:
L＝cot(α)×Ds；
ds is the distance between a non-central wavelength falling point corresponding to a characteristic peak of the standard light source and a central wavelength falling point; alpha is the angle between the non-central wavelength and the central wavelength corresponding to the characteristic peak of the standard light source.
By adopting the technical scheme, different motor steps correspond to different central wavelengths through the function relationship established in the front, so that the determined central wavelength can be selected, the calculation is carried out by utilizing the determined central wavelength, and the accuracy of calculating the equivalent distance L is improved.
Optionally, a certain characteristic peak a of the standard light source is vertically irradiated on the multi-point detector;
and adjusting the angle of the grating, enabling the certain characteristic peak a of the standard light source to irradiate the multi-point detector in a non-vertical manner, and calculating to obtain the distance Ds between a non-central wavelength falling point corresponding to the certain characteristic peak a of the standard light source and a central wavelength falling point corresponding to another characteristic peak b of the standard light source.
Optionally, according to the functional relationship; obtaining the wavelength value of non-central wavelength corresponding to a certain characteristic peak a of the standard light source and the wavelength value of central wavelength corresponding to another characteristic peak b of the standard light source, and calculating the diffraction angle theta of the central wavelength according to a grating formula 1 And diffraction angle theta of non-central wavelength 2 To obtain α = θ 1 -θ 2 。
By adopting the technical scheme, a certain characteristic peak of the standard light source vertically irradiates the multi-point detector, and the wavelength value of the characteristic peak can be obtained according to the functional relation between the characteristic peak and the step number of the motor; deflecting a certain characteristic peak of the standard light source to enable the certain characteristic peak to irradiate the multipoint detector in a non-vertical mode, enabling the step number of the motor to rotate by a certain angle, enabling the other characteristic peak of the standard light source to irradiate the multipoint detector in a vertical mode, obtaining the wavelength values of the characteristic peak which irradiates the multipoint detector in the non-vertical mode and the characteristic peak which irradiates the multipoint detector in the vertical mode according to the function relation of the characteristic peak and the step number of the motor, and calculating the included angle between the central wavelength and the non-central wavelength through a grating formula according to the wavelength values. And combining Ds to calculate the equivalent distance L. According to the scheme, the equivalent distance is quickly determined through the established functional relation, and the equivalent distance can be measured for multiple times, so that the accuracy of the equivalent distance is ensured, and the accuracy of a subsequent calibration result is improved.
Optionally, the distance D is:
D＝Δd×nd；
delta d is the size of a pixel point of the multipoint detector; nd is an index value of the pixel.
By adopting the technical scheme, the sizes of the pixel points of the multi-point detectors with different models are different, and the sizes of the pixel points of the multi-point detectors are determined after the models are selected; and nd is the number of pixels relative to the central pixel, so that the distance between the non-central wavelength drop point and the central wavelength drop point can be quickly determined by using a multi-point detector to collect the wavelength so as to facilitate calculation.
Optionally, in step S2, a multi-point detector is installed at the exit slit through a tool; the tool is used for adjusting the posture of the multipoint detector.
By adopting the technical scheme, the tool can be used for facilitating personnel to adjust the posture of the multipoint detector relative to the light outlet of the spectrometer, so that the light outlet focal plane (the collection plane of the multipoint detector) of the spectrometer is perpendicular to the standard light source to obtain the best resolution, and the accuracy of a calibration result is further improved.
Optionally, the motor for controlling the grating angle in step S1 drives the grating to rotate through the worm and gear assembly.
By adopting the technical scheme, the stability of controlling the grating angle is improved, and the accuracy and the repeatability of the wavelength irradiating the multipoint detector are ensured.
Optionally, the standard light source is a low-pressure mercury lamp light source.
By adopting the technical scheme, the low-pressure mercury lamp light source has a standard spectral line, and the standard light source with a recognized characteristic spectral line is adopted, so that the calculation and calibration of the spectrometer are facilitated.
Optionally, the functional relationship in step S1 is a trigonometric functional relationship:
W＝C×sin(α c )；
if α is c <0 then
W is the wavelength value of the standard light source, C is the grating calibration coefficient, T is the total step number of the stepping motor, Z is the zero offset, P is the step number of the stepping motor corresponding to the wavelength, alpha c Is the grating diffraction angle.
By adopting the technical scheme, the method is favorable for establishing the relation between the peak value of the characteristic peak of the standard light source and the motor step number for controlling the angle of the grating, so that the characteristic peak of the standard light source can be known according to the motor step number, the subsequent calibration of the spectrometer is favorable, and the grating can be adjusted at the same time, so that the grating can be corrected, and the adaptability of the spectrometer is improved.
In summary, the present application includes at least one of the following beneficial technical effects:
1. compare with the traditional mode that adopts many calibration spectral lines to calibrate, this application only needs can accomplish the calibration to the spectrometer through 1 standard spectral line, has simplified the calibration procedure, has reduced the loaded down with trivial details nature that needs many standard spectral lines to calibrate to the spectrometer in traditional calibration method, has effectively improved calibration efficiency under the accurate prerequisite of assurance calibration result.
2. The tool can be used for conveniently adjusting the posture of the multipoint detector relative to the light outlet of the spectrometer by personnel, so that the light outlet focal plane (the acquisition plane of the multipoint detector) of the spectrometer is perpendicular to the standard light source to obtain the best resolution, and the accuracy of the calibration result is improved.
3. The determination of the trigonometric function relationship is favorable for establishing the relationship between the peak value of the characteristic peak of the standard light source and the motor step number for controlling the angle of the grating, so that the characteristic peak of the standard light source can be obtained according to the motor step number, the subsequent calibration of the spectrometer is favorable, and the grating can be adjusted at the same time, so that the grating can be corrected, and the adaptability of the spectrometer is improved.
Drawings
FIG. 1 is an asymmetric non-intersecting C-T optical path diagram of a moving grating spectrometer in the related art.
Fig. 2 is a calibration state diagram of a calibration structure of a grating spectrometer according to an embodiment of the present application.
FIG. 3 is a schematic diagram of a calibration structure of a grating spectrometer according to an embodiment of the present application with an exit slit mounted thereon.
Fig. 4 is a graph of the number of stepper motor steps P as a function of the wavelength value W of the calibration light source.
Fig. 5 is a schematic diagram of the calibration of the grating according to the embodiment of the present application.
Fig. 6-7 are schematic diagrams illustrating the calculation of the distance D between the landing point of the non-central wavelength irradiated on the CCD and the landing point of the central wavelength of the standard light source according to the embodiment of the present application.
FIG. 8 is a schematic diagram of a multi-point detector illuminated perpendicularly to a characteristic peak of a standard light source according to an embodiment of the present invention.
FIG. 9 is a schematic diagram of a multi-point detector illuminated non-perpendicularly by a characteristic peak of a standard light source according to an embodiment of the present application.
Description of reference numerals:
10. a standard light source; 11. an inlet slit; 12. a plane mirror; 13. a spherical reflector; 14. a grating; 141. a circular truncated cone; 15. an aspherical mirror; 16. assembling; 17. a multi-point detector; 18. a computer; 19. an outlet slit; 20. and a data acquisition device.
Detailed Description
The present application is described in further detail below with reference to figures 1-9.
In the scheme of the application, the grating spectrometer of calibration chooses for use the movable grating spectrometer, and the movable grating spectrometer adopts the design of asymmetric non-crossed (czerny-turner, M type) light path, and asymmetric non-crossed light path is as shown in fig. 1, and asymmetric light path is higher than the light degree of consistency and the resolution ratio of symmetric light path, can guarantee the symmetry and the resolution ratio of light-emitting.
The embodiment of the application discloses a wavelength calibration method of a grating spectrometer. Referring to fig. 2, the wavelength calibration method requires the use of a grating spectrometer calibration structure, which includes a standard light source 10, an entrance slit 11, a plane mirror 12, a spherical mirror 13, a grating 14, an aspheric mirror 15, a multi-point detector 17, and a computer 18.
Light emitted by a standard light source 10 uniformly illuminates an entrance slit 11, is irradiated onto a grating 14 through a plane mirror 12 and a spherical mirror 13, is diffracted to an aspherical mirror 15 through the grating 14, and is irradiated onto a multi-point detector 17 through the aspherical mirror 15. The relationship between the pixels on the multi-point detector 17 and the rotation angle of the grating 14 is calibrated, and finally, the pixels on the multi-point detector 17 and the wavelength irradiated on the multi-point detector 17 generate a unique corresponding relationship.
In this embodiment, the multi-point detector is a CCD (linear photoelectric detector), which is easily available on the market, and is advantageous for reducing the cost.
The wavelength calibration method of the grating spectrometer comprises the following steps:
s1, establishing a functional relation between the peak value of the characteristic peak of the standard light source 10 and the step number of a motor for controlling the angle of the grating 14.
The standard light source 10 is a light source having a well-known characteristic line, such as a light source emitted from a mercury lamp, an argon lamp, or the like. Based on the diffraction principle of the grating 14, the wavelength of monochromatic light emitted from the standard light source 10 perpendicular to the exit of the spectrometer is the most accurate, and is defined as the center wavelength. Within a certain range of the central wavelength, the wavelength is in a linear distribution rule.
Referring to fig. 3, during calibration, the standard light source 10 is a low-pressure mercury lamp, an outlet slit 19 is installed at a light outlet of a spectrometer by using a mercury lamp standard spectral line calibration method, so that the standard light source 10 is ensured to output only light with a central wavelength perpendicular to the outlet slit 19, the light with the central wavelength is collected by matching a Photomultiplier (PMT) and a data collector 20, and then a functional relation between a peak value of a characteristic peak of the standard light source 10 and a motor step number for controlling the angle of the grating 14 is established by changing the angle of the grating 14.
The photomultiplier is a vacuum device sealed by glass, and includes a photocathode (photocathode), several dynodes (dynodes), and an Anode (Anode). Incident photons strike the photocathode, producing a photoelectric effect, and the generated photoelectrons are focused on the dynodes. The latter operates as an electron multiplier tube, with electrons accelerated to a dynode to produce a plurality of secondary electrons, typically at a potential difference of 100 to 200 volts per dynode. The secondary electron flow, like a waterfall, passes through a series of dynodes to multiply the electrons and finally reaches the anode. It can enhance the incoming weak optical signal to 10 8 And (4) enabling the optical signal to be measured.
Meanwhile, the grating 14 angle can be adjusted by matching a stepping motor with a precise worm and gear assembly to drive the grating 14 to rotate in angle. Referring to fig. 3, a circular truncated cone 141 is installed inside the spectrometer, the grating 14 is installed on the circular truncated cone 141, the stepping motor is matched with the precise worm and gear assembly to drive the circular truncated cone 141 to rotate, so that the angle of the grating 14 can be adjusted, and the accuracy and the repeatability of the wavelength irradiated on the multi-point detector 17 are guaranteed by adjusting the angle of the grating 14.
The establishment of the functional relationship between the peak value of the characteristic peak of the standard light source 10 and the step number of the motor for controlling the angle of the grating 14 comprises the following steps:
the first step is as follows: and determining the deviation of the step number of the stepping motor corresponding to the zero position of the stepping motor and the optical zero position, and defining the deviation as the zero offset.
Specifically, the zero position of the stepping motor is determined, during adjustment, the stepping motor drives the grating 14 to rotate, so that zero-order light reflected by the grating 14 from the standard light source 10 is vertically emitted to the exit slit 19 (the zero-order light is composite light which is directly emitted onto the grating and is not directly reflected by diffraction), at this time, the position of the grating 14 is determined as an optical zero position, and the difference value between the step number of the stepping motor corresponding to the optical zero position and the zero position of the stepping motor is zero offset.
The second step is that: the angle of the grating 14 is adjusted, the step number P of the stepping motor corresponding to each group of wavelengths and the wavelength value W of the standard light source 10 are recorded, and a function diagram of the step number P of the stepping motor and the wavelength value W of the standard light source 10 is established through each group of data, as shown in fig. 4, the abscissa is the step number P of the stepping motor corresponding to the wavelength, and the ordinate is the wavelength value W of the standard light source 10.
The function relation between the peak value of the characteristic peak of the standard light source 10 and the motor step number of the angle of the control grating 14 is obtained according to the function diagram as follows:
W＝C×sin(α c )；
if α is c <0 then
W is the wavelength value of the standard light source 10, C is the grating calibration coefficient, T is the total step number of the stepping motor, Z is the zero offset, P is the step number of the stepping motor corresponding to the wavelength, alpha c Is the grating diffraction angle.
Because of the zero point offset Z, when the grating 14 starts from the zero point of the stepping motor and the actual rotation angle is larger than 2 pi, the grating diffraction angle alpha c Negative values may occur during the calculation, when passing
And calculating the actually required numerical value.
Specifically, in one embodiment, the total number of steps of the stepping motor T =1152000 steps/turn; zero offset Z =6998 step; after the zero offset is determined (by mercury lamp zero position scanning), one characteristic peak is selected for scanning, for example, 435.83nm, the step number P =56360 corresponding to the peak value can be obtained, the raster correction coefficient C =1638.544 is further calculated, and the trigonometric function relationship between the peak value of the characteristic peak of the standard light source 10 and the motor step number for controlling the angle of the raster 14 can be determined according to the raster correction coefficient C.
By using the trigonometric function relationship, the wavelength value of the characteristic peak of the standard light source 10 can be obtained by knowing the number of steps of the motor for controlling the angle of the grating 14 during subsequent calculation.
The exit slit 19 is removed after the trigonometric relationship is established.
S2, calculating the distance D between the falling point of the non-central wavelength irradiated on the multi-point detector 17 and the falling point of the central wavelength of the standard light source 10.
Referring to fig. 2 and 5, a multi-point detector 17 is mounted at a light outlet of a spectrometer through a tool 16, the tool 16 is used for adjusting the posture of the multi-point detector 17, the tool 16 can adopt a structure that a stepping motor is matched with a precision worm and gear assembly to drive a tool circular table to rotate, and the tool 16 can drive the multi-point detector 17 to rotate, so that a light outlet focal plane (an acquisition plane of the multi-point detector 17) of the spectrometer is perpendicular to a standard light source 10 to obtain the best resolution.
In the present application, the multi-point detector adopts a linear photodetector, that is, the pixels (pixels) are arranged in a straight line, so the distance between the falling point of the non-central wavelength and the falling point of the central wavelength is the product of the difference between the pixel numbers of the two and the size (diameter) of each pixel.
The distance D between the falling point of any non-central wavelength irradiated on the multi-point detector 17 and the falling point of the central wavelength is as follows:
D＝Δd×nd；
delta d is the size of a pixel point of the multipoint detector; nd is the index value of the pixel, i.e. the few pixels relative to the central wavelength pixel. As shown in fig. 6 and 7, D = Δ D × 2 is exemplified.
And S3, referring to FIG. 5, calculating an equivalent distance L between the multipoint detector 17 and the grating 14 according to the trigonometric function relationship, wherein the equivalent distance L is defined as the distance between the central diffraction point of the grating 14 and the acquisition surface of the multipoint detector 17.
The equivalent distance L is:
L＝cot(α)×Ds；
ds is defined as the distance between the non-center wavelength falling point and the center wavelength falling point corresponding to the characteristic peak of the standard light source 10, and α is defined as the angle between the non-center wavelength and the center wavelength corresponding to the characteristic peak of the standard light source 10.
The specific calculation method of Ds is as follows:
referring to fig. 8, when a certain characteristic peak a of the standard light source 10 diffracted by the grating 14 is vertically irradiated on the multi-point detector 17, the number of steps of the stepping motor at the position of the grating 14 can be known, and thus the wavelength value of the certain characteristic peak a of the standard light source 10 can be known.
Referring to fig. 9, the angle of the grating 14 is adjusted by adjusting the number of steps of the stepping motor, so that the certain characteristic peak a of the standard light source 10 is irradiated on the multi-point detector 17 non-perpendicularly, at this time, the other characteristic peak b of the standard light source 10 is irradiated on the multi-point detector 17 perpendicularly, and the distance Ds between the non-center wavelength falling point corresponding to the certain characteristic peak a of the standard light source 10 and the center wavelength falling point corresponding to the other characteristic peak b of the standard light source 10 is calculated.
The specific calculation method of α is as follows:
referring to fig. 9, according to the trigonometric function relationship, a wavelength value of a non-central wavelength corresponding to a certain characteristic peak a of the standard light source 10 and a wavelength value of a central wavelength corresponding to another characteristic peak b of the standard light source 10 are obtained according to the number of steps of the stepping motor, and then a diffraction angle θ of the central wavelength is calculated according to a grating formula k λ = dsin θ 1 And diffraction angle theta of non-central wavelength 2 And calculating the angle alpha = theta between the non-central wavelength and the central wavelength corresponding to the characteristic peak of the standard light source 10 1 -θ 2 。
And then according to an equivalent distance L formula: l = cot (α) × Ds;
and calculating to obtain the equivalent distance L.
In one embodiment, α = -0.05032rad, ds = -14120um, and the equivalent distance L =280367.3um is calculated.
S4, referring to FIG. 5, according to the formula
Calculating the angular deviation alpha of any non-central wavelength from the central wavelength impinging on the multi-point detector 17 n 。
In one embodiment, distance D =2048um, the angular deviation α is calculated n ＝-0.007304rad。
S5, diffraction angle theta according to center wavelength of known standard light source 10 1 Calculating non-center of illumination onto the multi-spot detector 17Diffraction angle of wavelength theta n Comprises the following steps:
θ n ＝θ 1 -α n 。
in one embodiment, θ 1 =0.2189rad; calculating to obtain diffraction angle theta n ＝0.2262rad。
S6, calculating the wavelength value lambda of the non-central wavelength at any position on the multipoint detector 17 according to a grating formula n Comprises the following steps: lambda [ alpha ] n ＝dsinθ n /k。
In one embodiment, the wavelength value λ n ＝367.49nm。
S7, comparing and matching the positions of the characteristic spectral lines acquired by the spectrograph with recognized spectral lines, determining whether wavelength calibration is accurate, and if so, determining the corresponding relation between the wavelength and the pixels of the multipoint detector 17; if not, recalibration is performed until the wavelength to multipoint detector 17 pixel correspondence is determined.
Compare with the traditional mode that adopts many calibration spectral lines to calibrate, this application only needs can accomplish the calibration to the spectrometer through 1 standard spectral line, has simplified the calibration procedure, has reduced the loaded down with trivial details nature that needs many standard spectral lines to calibrate to the spectrometer in traditional calibration method, has effectively improved calibration efficiency under the accurate prerequisite of assurance calibration result.
The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.
Claims (10)
1. A wavelength calibration method of a grating spectrometer is characterized by comprising the following steps:
s1, establishing a functional relation between a peak value of a characteristic peak of a standard light source (10) and the number of motor steps for controlling the angle of a grating (14);
s2, a multi-point detector (17) is arranged at a light outlet of the spectrometer, a standard light source (10) irradiates the multi-point detector (17) after passing through the spectrometer, and the distance D between a falling point of the standard light source (10) irradiating the multi-point detector (17), wherein the falling point is located at a non-central wavelength and is opposite to a central wavelength falling point is calculated; the central wavelength is the wavelength vertical to the light outlet of the spectrometer;
s3, calculating the equivalent distance L between the multipoint detector (17) and the grating (14) through the functional relation; the equivalent distance L is the distance between the central diffraction point of the grating (14) and the acquisition surface of the multi-point detector (17);
s4, according to the formula
Calculating the angular deviation alpha of the non-central wavelength from the central wavelength impinging on the multi-point detector (17) n ；
S5, diffraction angle theta according to center wavelength of standard light source (10) 1 Calculating the diffraction angle theta of non-central wavelengths impinging on the multi-point detector (17) n Comprises the following steps:
θ n ＝θ 1 -α n ；
s6, calculating the wavelength value lambda of the non-central wavelength irradiated on the multi-point detector (17) according to a grating formula n Comprises the following steps:
λ n ＝dsinθ n /k；
and S7, calibrating according to the comparison and matching of the position of the characteristic spectral line acquired by the spectrometer and the acknowledged spectral line.
2. The method for wavelength calibration of a grating spectrometer according to claim 1, wherein the step S1 comprises:
s10: an outlet slit (19) is arranged at a light outlet of the spectrometer, and the central wavelength of the spectrometer is calibrated according to a calibration method of a monochromator;
s11: the exit slit (19) is removed after calibration.
3. The method for wavelength calibration of a grating spectrometer of claim 2, wherein: the equivalent distance L is as follows:
L＝cot(α)×Ds；
ds is the distance between a non-central wavelength falling point corresponding to a characteristic peak of the standard light source (10) and a central wavelength falling point; alpha is the angle between the non-central wavelength and the central wavelength corresponding to the characteristic peak of the standard light source (10).
4. The method for wavelength calibration of a grating spectrometer of claim 3, wherein:
enabling a certain characteristic peak a of a standard light source (10) to vertically irradiate a multi-point detector (17);
and adjusting the angle of the grating (14), enabling the certain characteristic peak a of the standard light source (10) to be irradiated on the multi-point detector (17) in a non-vertical mode, and calculating to obtain the distance Ds between a non-central wavelength falling point corresponding to the certain characteristic peak a of the standard light source (10) and a central wavelength falling point corresponding to another characteristic peak b of the standard light source (10).
5. The method for wavelength calibration of a grating spectrometer of claim 4, wherein: according to the functional relation; obtaining a wavelength value of a non-central wavelength corresponding to a certain characteristic peak a of the standard light source (10) and a wavelength value of a central wavelength corresponding to another characteristic peak b of the standard light source (10), and calculating a diffraction angle theta of the central wavelength according to a grating formula 1 And diffraction angle theta of non-central wavelength 2 To obtain α = θ 1 -θ 2 。
6. The method for wavelength calibration of a grating spectrometer of claim 1, wherein: the distance D is as follows:
D＝Δd×nd；
delta d is the size of a pixel point of the multipoint detector; nd is an index value of the pixel.
7. The method for wavelength calibration of a grating spectrometer of claim 2, wherein: in the step S2, a multipoint detector (17) is installed at the position of the outlet slit (19) through a tool (16); the tool (16) is used for adjusting the posture of the multipoint detector (17).
8. The method for wavelength calibration of a grating spectrometer of claim 1, wherein: and in the step S1, the motor for controlling the angle of the grating (14) drives the grating (14) to rotate through the worm and gear assembly.
9. The method for wavelength calibration of a grating spectrometer of claim 1, wherein: the standard light source (10) adopts a low-pressure mercury lamp light source.
10. The method for wavelength calibration of a grating spectrometer of claim 1, wherein: the functional relationship in step S1 is a trigonometric functional relationship:
W＝C×sin(α c )；
if α is c <0 then
W is the wavelength value of the standard light source, C is the grating calibration coefficient, T is the total step number of the stepping motor, Z is the zero offset, P is the step number of the stepping motor corresponding to the wavelength, alpha c Is the grating diffraction angle.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211015243.3A CN115507947A (en) | 2022-08-23 | 2022-08-23 | Wavelength calibration method for grating spectrometer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211015243.3A CN115507947A (en) | 2022-08-23 | 2022-08-23 | Wavelength calibration method for grating spectrometer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115507947A true CN115507947A (en) | 2022-12-23 |
Family
ID=84501847
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211015243.3A Withdrawn CN115507947A (en) | 2022-08-23 | 2022-08-23 | Wavelength calibration method for grating spectrometer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115507947A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116625959A (en) * | 2023-07-17 | 2023-08-22 | 北京卓立汉光仪器有限公司 | Wavelength calibration method of grating spectrometer |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107490433A (en) * | 2017-04-13 | 2017-12-19 | 中国科学院长春光学精密机械与物理研究所 | A kind of spectrum calibration method and grating spectrograph based on grating spectrograph |
-
2022
- 2022-08-23 CN CN202211015243.3A patent/CN115507947A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107490433A (en) * | 2017-04-13 | 2017-12-19 | 中国科学院长春光学精密机械与物理研究所 | A kind of spectrum calibration method and grating spectrograph based on grating spectrograph |
Non-Patent Citations (1)
| Title |
|---|
| 迟明波: "阵列狭缝编码光谱仪的研制及其关键技术" * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116625959A (en) * | 2023-07-17 | 2023-08-22 | 北京卓立汉光仪器有限公司 | Wavelength calibration method of grating spectrometer |
| CN116625959B (en) * | 2023-07-17 | 2023-11-10 | 北京卓立汉光仪器有限公司 | Wavelength calibration method of grating spectrometer |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109387284B (en) | Imaging spectrometer radiation parameter and imaging parameter calibration device and method | |
| Brown et al. | The SSRL ultrahigh vacuum grazing incidence monochromator: design considerations and operating experience | |
| CA1115545A (en) | Spectrophotometer | |
| US3874799A (en) | Method and apparatus for color spectrophotometry | |
| Polder et al. | Calibration and characterisation of imaging spectrographs | |
| US5686993A (en) | Method of and apparatus for measuring film thickness | |
| JP4534487B2 (en) | Assembly and method for wavelength calibration of an echelle spectrometer | |
| CN115507947A (en) | Wavelength calibration method for grating spectrometer | |
| Parfenov et al. | Calibration of the spectral sensitivity of instruments for the near infrared region | |
| US20190186992A1 (en) | Spectrometer arrangement, method for producing a two-dimensional spectrum by means of such a spectrometer arrangement | |
| EP0344782B1 (en) | Standardization of spectral lines | |
| Radziuk et al. | Spectrometer system for simultaneous multi-element electrothermal atomic absorption spectrometry using line sources and Zeeman-effect background correction | |
| US7349103B1 (en) | System and method for high intensity small spot optical metrology | |
| US5721613A (en) | Fluorescence spectrometer | |
| CN113175883A (en) | Light source normalization processing method of spectrum confocal measurement system | |
| CN109387283A (en) | Method of the near ultraviolet near infrared spectrum radiometer and its calibrating method and measurement integrating sphere light source spectral radiance | |
| Gardner et al. | Efficiency variations of UVCS/SOHO based on laboratory measurements of replica gratings | |
| JP2005062192A (en) | Method for obtaining angle spectrum, gonio spectrophotometer and method for inspecting product during machining | |
| Key et al. | The establishment of ultraviolet spectral emission scales using synchrotron radiation | |
| Becker-Ross et al. | A scanning echelle monochromator for ICP-OES with dynamic wavelength stabilization and CCD detection | |
| CN113188767B (en) | Ultraviolet lens reflection, transmissivity test and ultraviolet imaging system calibration device and method | |
| US3247759A (en) | Spectrometer with multiple entrance slits | |
| CN111504465A (en) | Colorimeter matching method, colorimeter correction method and system | |
| MacDonald | Determining camera spectral responsivity with multispectral transmission filters | |
| JPH10142152A (en) | Measuring method and device of quantum efficiency of fluorescent material |
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 | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20221223 |
|
| WW01 | Invention patent application withdrawn after publication |