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CN-115541512-B - System and method for measuring transmission spectrum matrix and absorbance spectrum matrix

CN115541512BCN 115541512 BCN115541512 BCN 115541512BCN-115541512-B

Abstract

The invention discloses a measurement system of a transmission spectrum matrix and an absorbance spectrum matrix, which comprises an infrared light source, a collimating lens, an interference system, a polarizing system, a sample bin, a polarization analysis system, a lens, a detector and a computer processing system, wherein the infrared light source, the collimating lens, the interference system, the polarizing system, the sample bin, the polarization analysis system, the lens, the detector and the computer processing system are sequentially arranged along an optical path, the interference system comprises a beam splitter, a fixed mirror and a movable mirror, the beam splitter is a cube component, the surface opposite to the collimating lens in four surfaces along the circumferential direction of the beam splitter is a surface A, the surface A is sequentially provided with a surface B, a surface C and a surface D along the clockwise direction, the fixed mirror is arranged at the surface B, the movable mirror is arranged at the surface C, the polarizing system is arranged at the surface D, the polarizer and the 1/4 wave plate with the extinction ratio sequentially arranged along the optical path, and the computer processing system is used for acquiring polarization information and calculating to obtain the transmission spectrum matrix and the absorbance spectrum matrix. The invention also discloses a measuring method of the measuring system of the transmission spectrum matrix and the absorbance spectrum matrix.

Inventors

  • WANG WEI
  • ZANG MENGMENG
  • PAN ZHONGBAO

Assignees

  • 江苏科技大学

Dates

Publication Date
20260512
Application Date
20220928

Claims (7)

  1. 1. A method for measuring a transmission spectrum matrix and an absorbance spectrum matrix is characterized by comprising the following steps: The method comprises the steps of 1, arranging an infrared light source (1), a collimating lens (2), an interference system, a sample bin (6), a lens (7) and a detector (8) along an optical path, wherein the infrared light source (1) and the collimating lens (2) are parallel and oppositely spaced by 5cm, a surface A of a beam splitter (3) and the collimating lens (2) are parallel and oppositely spaced by 8cm, a fixed mirror (4) is parallel and oppositely arranged at a position 10cm away from a surface B, a movable mirror (5) is parallel and oppositely arranged at a position 10cm away from a surface C, the sample bin (6), the lens (7) and the detector (8) are sequentially arranged at a position D at intervals of 15cm in opposite directions, connecting the detector (8) with the computer system, turning on the infrared light source (1), and preparing measured data after the infrared light source (1) is stable; Step 2, arranging a second polarizer (9) in parallel and opposite directions at a position 10cm away from the sample bin (6), sequentially adjusting the second polarizer (9) to 0 degrees, 45 degrees, 90 degrees and 135 degrees respectively, and measuring background interference data without modulation; step 3, an achromatic 1/4 wave plate II (10) is arranged in parallel and opposite directions between a sample bin (6) and a polarizer II (9), and the polarizer II (9) is sequentially adjusted to 45 degrees and 135 degrees respectively to measure background interference data without modulation; Step 4, arranging polarizers I (11) in parallel and opposite directions at a position 5cm away from a surface D of a beam splitter (3), adjusting the polarizers I (11) to 0 degrees, removing an achromatic 1/4 wave plate II (10), sequentially adjusting the polarizers II (9) to 0 degrees, 45 degrees, 90 degrees and 135 degrees respectively, and measuring background interference data modulated by 0 degrees; Step 5, an achromatic 1/4 wave plate II (10) is arranged in parallel and opposite directions between the sample bin (6) and the polarizer II (9), and the polarizer II (9) is sequentially and respectively adjusted to 45 degrees and 135 degrees to measure background interference data modulated by 0 degrees; Step 6, the first polarizer (11) is adjusted to 45 degrees, the achromatic 1/4 wave plate (10) is removed, the second polarizer (9) is sequentially adjusted to 0 degrees, 45 degrees, 90 degrees and 135 degrees respectively, and background interference data modulated by 45 degrees are measured; step 7, arranging achromatic 1/4 wave plate two (10) in parallel and opposite directions between the sample bin (6) and the polarizer two (9), and sequentially adjusting the polarizer two (9) to 45 degrees and 135 degrees respectively to measure and modulate background interference data of 45 degrees; Step 8, arranging an achromatic 1/4 wave plate I (12) in parallel and opposite directions between a polarizer I (11) and a sample bin (6), taking out the achromatic 1/4 wave plate II (10), sequentially adjusting the polarizer II (9) to 0 degree, 45 degree, 90 degree and 135 degree respectively, and measuring the background interference data of the modulated circular polarization; Step 9, arranging achromatic 1/4 wave plate two (10) in parallel and opposite directions between the sample bin (6) and the polarizer two (9), sequentially adjusting the polarizer two (9) to 45 degrees and 135 degrees respectively, and measuring background interference data of the modulated circular polarization; Step 10, placing a sample to be measured in a sample bin (6), and repeating the steps two to eight to measure four groups of sample interference data; step 11, the 48 interferograms obtained in the step are subjected to signal processing through a computer processing system, and the obtained interference data are processed according to a formula (1) Conversion to spectral data ; (1) Step 12, converting each group of 6 spectrum data into 4 Stokes vectors containing all polarization spectrum information by using a formula (2); (2) step 13, calculating the Stokes vector by using the formula (3) ; (3) Step 14, utilizing the formula (4) pair Further information processing of the matrix to obtain ; (4)。
  2. 2. A measurement system for realizing the measurement method of the transmission spectrum matrix and the absorbance spectrum matrix according to claim 1, comprising an infrared light source (1), a collimating lens (2), an interference system, a sample bin (6), a lens (7) and a detector (8) which are sequentially arranged at intervals, wherein a polarizing system for modulating the infrared light source before entering a sample is arranged between the interference system and the sample bin (6), a polarization analysis system for modulating the emergent infrared light source is arranged between the sample bin (6) and the lens (7) at intervals, the detector (8) is connected with a computer processing system through a data line, the interference system comprises a beam splitter (3), a fixed mirror (4) and a movable mirror (5), wherein the beam splitter (3) is a cube component, the surface which is opposite to the collimating lens (2) along four surfaces in the circumferential direction of the beam splitter is a surface A, and is sequentially a surface B, a surface C and a surface D along the clockwise direction; The polarizing system consists of a polarizer I (11) and an achromatic 1/4 wave plate I (12) which are sequentially arranged at intervals, wherein the polarizer I (11) and a surface D of the beam splitter (3) are arranged at opposite intervals, and the achromatic 1/4 wave plate I (12) and a sample bin (6) are arranged at opposite intervals; The polarization analysis system consists of an achromatic 1/4 wave plate II (10) and a polarizer II (9) which are sequentially arranged at intervals, wherein the achromatic 1/4 wave plate II (10) and the sample bin (6) are arranged at intervals in opposite directions, and the polarizer II (9) and the lens (7) are arranged at intervals in opposite directions; Computer processing system with interferometric data recovery Stokes vectors and transmission spectrum matrix calculation And absorbance spectrum A matrix function processing system; The computer processing system processes the signals and the obtained interference data is processed according to the formula (1) Conversion to spectral data ; (1) Converting each set of 6 spectral data into 4 Stokes vectors containing all polarization spectral information using equation (2); (2) Calculating the Stokes vector by using a formula (3) ; (3) Using the pair of formula (4) Further information processing of the matrix to obtain ; (4)。
  3. 3. The measuring system according to claim 2, characterized in that the distance at which the fixed mirrors (4) are arranged parallel to each other at the distance plane B is 10cm to 15cm.
  4. 4. The measuring system according to claim 2, characterized in that the distance of the moving mirror (5) placed parallel to each other at the distance plane C is 10 cm-15 cm.
  5. 5. The measurement system according to claim 2, wherein the first polarizer (11) and the second polarizer (9) are provided with an outer frame rotating frame, and the outer frame rotating frame is provided with rotation angle scale marks.
  6. 6. The measurement system of claim 2, wherein the first polarizer (11) and the second polarizer (9) are each a thin film polarizer WP25M-UB of cord Lei Bo, and wherein the first achromatic 1/4 waveplate (12) and the second achromatic 1/4 waveplate (10) are each Retarder.
  7. 7. The measurement system according to claim 2, wherein a sample platform for carrying the solid sample and the liquid sample is arranged in the sample chamber (6), and round holes with diameters of 4-7 cm are formed on two wall surfaces perpendicular to the optical path of the sample chamber (6) and coaxial with the optical path.

Description

System and method for measuring transmission spectrum matrix and absorbance spectrum matrix Technical Field The invention belongs to the technical field of spectrum detection instruments, and relates to a system and a method for measuring a transmission spectrum matrix and an absorbance spectrum matrix. Background The object transmittance refers to the ratio of the light flux transmitted by the object to the incident light flux, the intensity of the transmitted light radiation energy of the object is marked, and the spectral transmittance refers to the transmittance of the object to monochromatic light with a certain wavelength. Absorbance is a method of measuring how much light a substance absorbs by measuring the intensity of light as it passes through a sample solution. The basic principle is that each compound absorbs or transmits light over a range of wavelengths. This measurement method can also be used to measure the amount of known chemicals. With the development of science, the contribution of spectrum is larger and larger, and the application of spectroscopy and spectral analysis in various fields, such as detection of substance components, detection of crop diseases and insects, detection of substance quality and the like, is also wider and wider. Absorbance is one of the most commonly used quantitative analysis methods in chemical, physical, biochemical, material chemical engineering and clinical application fields. These are mainly achieved by analyzing the absorption spectrum or transmission spectrum of a substance, so that measuring the transmittance and absorbance is of great importance, thus indicating how accurately to measure the T (k) transmission spectrum matrix and the a (k) absorbance spectrum matrix of an unknown sample is of great importance in terms of material analysis. Stokes vector (S 0,S1,S2,S3)T (superscript T stands for transpose) describes the polarization state of light as a one-dimensional vector; according to the disclosure of the patent application 202111181474.7, a polarizer accessory is added to a traditional Fourier infrared spectrometer, and then a one-dimensional array of Stokes vectors is obtained by measuring according to a proposed six-step method, but since both a T (k) transmission spectrum array and an A (k) absorbance spectrum array are 4×4 arrays, four sets of linearly independent Stokes vectors are needed for recovering the T (k) transmission spectrum array and the A (k) absorbance spectrum array, and the patent and the prior art cannot obtain 4 sets of linearly independent Stokes vectors at present, so that analysis and application of research and development of related technologies are affected. Disclosure of Invention The invention aims to overcome the problems and defects in the prior art and provide a system and a method for measuring a transmission spectrum matrix and an absorbance spectrum matrix. The T (k) (transmission spectrum) spectrum matrix and the A (k) (absorbance spectrum) spectrum matrix containing all polarization optical characteristic information can be recovered by the measuring system. In order to achieve the above purpose, the technical scheme adopted by the invention for solving the technical problems is as follows: The measuring system for the transmission spectrum matrix and the absorbance spectrum matrix comprises an infrared light source 1, a collimating lens 2, an interference system, a sample bin 6, a lens 7 and a detector 8 which are sequentially arranged at intervals, and is characterized in that a polarizing system for modulating the infrared light source before entering a sample is arranged between the interference system and the sample bin 6 at intervals, a polarization analyzing system for modulating the emergent infrared light source is arranged between the sample bin 6 and the lens 7 at intervals, the detector 8 is connected with a computer processing system through a data line, the interference system comprises a beam splitter 3, a fixed mirror 4 and a movable mirror 5, wherein the beam splitter 3 is a cube component, the surface, opposite to the collimating lens 2, of four surfaces in the circumferential direction is a surface A, a surface B, a surface C and a surface D are sequentially arranged between the interference system and the sample bin 6 at intervals, the fixed mirror 4 is arranged in parallel opposite directions at a distance surface B, and the movable mirror 5 is arranged in parallel opposite directions at a distance surface C. Further preferably, the polarizing system is composed of a polarizer 11 and an achromatic 1/4 wave plate 12 which are sequentially arranged at intervals, wherein the polarizer 11 and the beam splitter 3 face D are arranged at opposite intervals, and the achromatic 1/4 wave plate 12 and the sample bin 6 are arranged at opposite intervals. Further preferably, the polarization analysis system is composed of an achromatic 1/4 wave plate II 10 and a polarizer II 9 which are sequentially